Merge pull request #4829 from JohnChen0/master

[platform/upstream/coreclr.git] / src / jit / morph.cpp

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

/*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XX                                                                           XX
XX                          Morph                                            XX
XX                                                                           XX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
*/

#include "jitpch.h"
#ifdef _MSC_VER
#pragma hdrstop
#endif

#include "allocacheck.h"     // for alloca

/*****************************************************************************/

// Split a tree at the given point
// -- Introduces a new temporary variable
// -- evaluates *splitPoint into the new temp, in a new statement inserted before 'stmt'
// -- substitutes the temporary for '*splitPoint' in 'stmt'
// '*splitpoint' must be a node in 'stmt', which is within 'blk', and 'splitpoint' is a pointer
// to the link to that node, contained in its parent node.
GenTree* Compiler::fgMorphSplitTree(GenTree** splitPoint, // where to split
                                    GenTree* stmt,        // top level statement housing this tree
                                    BasicBlock* blk)      // block we are in
{
    GenTree* newTree;
    GenTree* temp;

    if ((*splitPoint)->OperIsAssignment())
    {
        // it's already being assigned so don't introduce a new one
        newTree = *splitPoint;
        temp = (*splitPoint)->gtGetOp1();
    }
    else
    {
        unsigned lclNum = lvaGrabTemp(true DEBUGARG("split tree"));
        newTree = gtNewTempAssign(lclNum, *splitPoint);
        temp = gtNewLclvNode(lclNum, (*splitPoint)->TypeGet());
    }

    GenTreePtr asg  = gtNewStmt(newTree);

    *splitPoint = temp;

    fgInsertStmtBefore(blk, stmt, asg);

    return asg;
}

// state carried over the tree walk, to be used in making
// a splitting decision.
struct SplitData
{
    // number of calls seen
    size_t count;

    // callback to determine if we should split here
    Compiler::fgSplitPredicate* pred;

    // root stmt of tree being processed
    GenTree* root;
};


#ifdef _TARGET_ARM_
// Returns true if we should split the tree above this node.
// For ARM FP, handling multiple calls per tree via a local and
// greedy register allocator could result in a lot of shuffling.
// So let the global register allocator handle these cases.
bool shouldSplitARM(GenTree* tree, GenTree* parent, Compiler::fgWalkData* data)
{
    if (tree->IsCall()
        && varTypeIsFloating(tree)
        && parent
        && !parent->OperIsAssignment())
    {
        // increment call count
        SplitData* tmpState = (SplitData*) data->pCallbackData;
        tmpState->count++;

        return tmpState->count > 1;
    }
    else
    {
        return false;
    }
}
#endif // _TARGET_ARM_

// Callback for the tree walker, called once per node.
// Determines if we want to split, performs the split, and then processes the rest of the tree
Compiler::fgWalkResult Compiler::fgSplitHelper(GenTree** ppTree, fgWalkData* data)
{
    GenTree* tree = *ppTree;
    Compiler* comp = data->compiler;

    SplitData* tmpState = (SplitData*) data->pCallbackData;

    fgSplitPredicate* pred = tmpState->pred;

    if (pred(tree, data->parent, data)) // does this look like somewhere we want to split?
    {
        //printf("tmpstate2 = %d %p r:%p tmp:%p tree:%p\n", tmpState->count, tmpState->pred, tmpState->root, tmpState, tree);
        GenTree* result = comp->fgMorphSplitTree(ppTree, tmpState->root, comp->compCurBB);

        GenTree* oldStatement = comp->compCurStmt;
        comp->compCurStmt = result;

        // because we are doing this in pre-order we also have to process
        // the subtree that we have just split off
        comp->fgSplitProcessOneTree(result, pred);

        // restore it
        comp->compCurStmt = oldStatement;

        return Compiler::WALK_SKIP_SUBTREES;
    }
    //else       printf("tmpstate3 = %d %p r:%p tmp:%p tree:%p\n", tmpState->count, tmpState->pred, tmpState->root, tmpState, tree);

    return Compiler::WALK_CONTINUE;
}

void Compiler::fgSplitProcessOneTree(GenTree* tree, fgSplitPredicate pred)
{
    SplitData tmpState = {0};
    tmpState.pred = pred;
    tmpState.root = tree;

    fgWalkTreePre(&(tree->gtStmt.gtStmtExpr),
                  fgSplitHelper,
                  (void*) &tmpState);
}

// Split expression trees at points which in the case of ARM this is done.
void Compiler::fgSplitMethodTrees(void)
{
#ifndef _TARGET_ARM_
    return;
#else // _TARGET_ARM_
    for (BasicBlock* block = fgFirstBB; block; block = block->bbNext)
    {
        compCurBB = block;
        for (GenTree* tree = block->bbTreeList; tree; tree = tree->gtNext)
        {
            assert(tree != tree->gtNext);
            fgSplitProcessOneTree(tree, shouldSplitARM);
        }
    }
#endif // _TARGET_ARM_
}


// Convert the given node into a call to the specified helper passing
//  the given argument list.
// Tries to fold constants and also adds an edge for overflow exception
// returns the morphed tree
GenTreePtr Compiler::fgMorphCastIntoHelper(GenTreePtr tree,
                                           int        helper,
                                           GenTreePtr oper)
{
    GenTree *result;

    /* If the operand is a constant, we'll try to fold it */
    if  (oper->OperIsConst())
    {
        GenTreePtr oldTree = tree;

        tree = gtFoldExprConst(tree);    // This may not fold the constant (NaN ...)

        if (tree != oldTree)
            return fgMorphTree(tree);
        else if (tree->OperKind() & GTK_CONST)
            return fgMorphConst(tree);

        // assert that oper is unchanged and that it is still a GT_CAST node
        noway_assert(tree->gtCast.CastOp() == oper);
        noway_assert(tree->gtOper == GT_CAST);
    }
    result = fgMorphIntoHelperCall(tree, helper, gtNewArgList(oper));
    assert(result == tree);
    return result;
}


/*****************************************************************************
 *
 *  Convert the given node into a call to the specified helper passing
 *  the given argument list.
 */

GenTreePtr          Compiler::fgMorphIntoHelperCall(GenTreePtr      tree,
                                                    int             helper,
                                                    GenTreeArgList* args)
{
    tree->ChangeOper(GT_CALL);

    tree->gtFlags              |= GTF_CALL;
    tree->gtCall.gtCallType     = CT_HELPER;
    tree->gtCall.gtCallMethHnd  = eeFindHelper(helper);
    tree->gtCall.gtCallArgs     = args;
    tree->gtCall.gtCallObjp     = NULL;
    tree->gtCall.gtCallLateArgs = NULL;
    tree->gtCall.fgArgInfo      = NULL;
    tree->gtCall.gtRetClsHnd    = NULL;
    tree->gtCall.gtCallRegUsedMask = RBM_NONE;
    tree->gtCall.gtCallMoreFlags   = 0;
    tree->gtCall.gtInlineCandidateInfo = NULL;
    tree->gtCall.gtControlExpr = NULL;

#ifdef FEATURE_READYTORUN_COMPILER
    tree->gtCall.gtEntryPoint.addr = nullptr;
#endif

    /* Perform the morphing */

    tree = fgMorphArgs(tree->AsCall());

    return tree;
}

/*****************************************************************************
 * This node should not be referenced by anyone now. Set its values to garbage
 * to catch extra references
 */

inline
void                DEBUG_DESTROY_NODE(GenTreePtr tree)
{
#ifdef DEBUG
    // printf("DEBUG_DESTROY_NODE for [0x%08x]\n", tree);

    // Save gtOper in case we want to find out what this node was
    tree->gtOperSave    = tree->gtOper;

    tree->gtType        = TYP_UNDEF;
    tree->gtFlags      |= 0xFFFFFFFF & ~GTF_NODE_MASK;
    if (tree->OperIsSimple())
    {
        tree->gtOp.gtOp1    =
        tree->gtOp.gtOp2    = NULL;
    }
    // Must do this last, because the "gtOp" check above will fail otherwise.
    // Don't call SetOper, because GT_COUNT is not a valid value
    tree->gtOper        = GT_COUNT;
#endif
}


/*****************************************************************************
 *
 *  Determine if a relop must be morphed to a qmark to manifest a boolean value.
 *  This is done when code generation can't create straight-line code to do it.
 */
bool                Compiler::fgMorphRelopToQmark(GenTreePtr tree)
{
#ifndef LEGACY_BACKEND
    return false;
#else // LEGACY_BACKEND
    return (genActualType(tree->TypeGet()) == TYP_LONG) ||
           varTypeIsFloating(tree->TypeGet());
#endif // LEGACY_BACKEND
}


/*****************************************************************************
 *
 *  Morph a cast node (we perform some very simple transformations here).
 */

#ifdef _PREFAST_
#pragma warning(push)
#pragma warning(disable:21000) // Suppress PREFast warning about overly large function
#endif
GenTreePtr          Compiler::fgMorphCast(GenTreePtr tree)
{
    noway_assert(tree->gtOper == GT_CAST);
    noway_assert(genTypeSize(TYP_I_IMPL) == sizeof(void*));

    /* The first sub-operand is the thing being cast */

    GenTreePtr      oper    = tree->gtCast.CastOp();
    var_types       srcType = genActualType(oper->TypeGet());
    unsigned        srcSize;

    var_types       dstType = tree->CastToType();
    unsigned        dstSize = genTypeSize(dstType);

    // See if the cast has to be done in two steps.  R -> I
    if (varTypeIsFloating(srcType) && varTypeIsIntegral(dstType))
    {
        // Only x86 must go through TYP_DOUBLE to get to all
        // integral types everybody else can get straight there
        // except for when using helpers
        if (srcType == TYP_FLOAT
#if !FEATURE_STACK_FP_X87

#if defined(_TARGET_ARM64_)
            // Amd64: src = float, dst is overflow conversion.
            // This goes through helper and hence src needs to be converted to double.
            &&  tree->gtOverflow()
#elif defined(_TARGET_AMD64_)
            // Amd64: src = float, dst = uint64 or overflow conversion.
            // This goes through helper and hence src needs to be converted to double.
            && (tree->gtOverflow() || (dstType == TYP_ULONG))
#elif  defined(_TARGET_ARM_)
            // Arm: src = float, dst = int64/uint64 or overflow conversion.
            && (tree->gtOverflow() || varTypeIsLong(dstType))
#endif

#endif // FEATURE_STACK_FP_X87
            )
        {
            oper = gtNewCastNode(TYP_DOUBLE, oper, TYP_DOUBLE);
        }

        // do we need to do it in two steps R -> I, '-> smallType
#if defined(_TARGET_ARM64_) || defined(_TARGET_AMD64_)
        if (dstSize < genTypeSize(TYP_INT))
        {
            oper = gtNewCastNodeL(TYP_INT, oper, TYP_INT);
            oper->gtFlags |= (tree->gtFlags & (GTF_UNSIGNED|GTF_OVERFLOW|GTF_EXCEPT));
            tree->gtFlags &= ~GTF_UNSIGNED;
        }
#else
        if (dstSize < sizeof(void*))
        {
            oper = gtNewCastNodeL(TYP_I_IMPL, oper, TYP_I_IMPL);
            oper->gtFlags |= (tree->gtFlags & (GTF_OVERFLOW|GTF_EXCEPT));
        }
#endif
        else
        {
            /* Note that if we need to use a helper call then we can not morph oper */
            if (!tree->gtOverflow())
            {
#ifdef _TARGET_ARM64_    // On ARM64 All non-overflow checking conversions can be optimized
                goto OPTIMIZECAST;
#else
                switch (dstType)
                {
                case TYP_INT:
#ifdef _TARGET_X86_     // there is no rounding convert to integer instruction on ARM or x64 so skip this
                    if ((oper->gtOper == GT_INTRINSIC) &&
                        (oper->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Round))
                    {
                        /* optimization: conv.i4(round.d(d)) -> round.i(d) */
                        oper->gtType = dstType;
                        return fgMorphTree(oper);
                    }
                    // if SSE2 is not enabled, we need the helper
                    else if (!opts.compCanUseSSE2)
                    {
                        return fgMorphCastIntoHelper(tree, CORINFO_HELP_DBL2INT, oper);
                    }
                    else
#endif // _TARGET_X86_
                    {
                        goto OPTIMIZECAST;
                    }
#if defined(_TARGET_ARM_) || defined(_TARGET_AMD64_)
                case TYP_UINT:  goto OPTIMIZECAST;
#else // _TARGET_ARM_
                case TYP_UINT:  return fgMorphCastIntoHelper(tree, CORINFO_HELP_DBL2UINT, oper);
#endif // _TARGET_ARM_

#ifdef _TARGET_AMD64_
                // SSE2 has instructions to convert a float/double directly to a long
                case TYP_LONG:  goto OPTIMIZECAST;
#else
                case TYP_LONG:  return fgMorphCastIntoHelper(tree, CORINFO_HELP_DBL2LNG, oper);
#endif //_TARGET_AMD64_
                case TYP_ULONG: return fgMorphCastIntoHelper(tree, CORINFO_HELP_DBL2ULNG, oper);
                default: break;
                }
#endif // _TARGET_ARM64_
            }
            else
            {
                switch (dstType)
                {
                case TYP_INT:   return fgMorphCastIntoHelper(tree, CORINFO_HELP_DBL2INT_OVF, oper);
                case TYP_UINT:  return fgMorphCastIntoHelper(tree, CORINFO_HELP_DBL2UINT_OVF, oper);
                case TYP_LONG:  return fgMorphCastIntoHelper(tree, CORINFO_HELP_DBL2LNG_OVF, oper);
                case TYP_ULONG: return fgMorphCastIntoHelper(tree, CORINFO_HELP_DBL2ULNG_OVF, oper);
                default: break;
                }
            }
            noway_assert(!"Unexpected dstType");
        }
    }
#ifndef _TARGET_64BIT_
    // The code generation phase (for x86 & ARM32) does not handle casts
    // directly from [u]long to anything other than [u]int. Insert an
    // intermediate cast to native int.
    else if (varTypeIsLong(srcType) && varTypeIsSmall(dstType))
    {
        oper = gtNewCastNode(TYP_I_IMPL, oper, TYP_I_IMPL);
        oper->gtFlags |= (tree->gtFlags & (GTF_OVERFLOW|GTF_EXCEPT|GTF_UNSIGNED));
        tree->gtFlags &= ~GTF_UNSIGNED;
    }
#endif //!_TARGET_64BIT_

#ifdef _TARGET_ARM_
    else if ((dstType == TYP_FLOAT) && (srcType == TYP_DOUBLE) && (oper->gtOper == GT_CAST) && !varTypeIsLong(oper->gtCast.CastOp()))
    {
        // optimization: conv.r4(conv.r8(?)) -> conv.r4(d)
        // except when the ultimate source is a long because there is no long-to-float helper, so it must be 2 step.
        // This happens semi-frequently because there is no IL 'conv.r4.un'
        oper->gtType = TYP_FLOAT;
        oper->CastToType() = TYP_FLOAT;
        return fgMorphTree(oper);
    }
    // converts long/ulong --> float/double casts into helper calls.
    else if (varTypeIsFloating(dstType) && varTypeIsLong(srcType))
    {
        if (dstType == TYP_FLOAT)
        {
            // there is only a double helper, so we
            // - change the dsttype to double
            // - insert a cast from double to float
            // - recurse into the resulting tree
            tree->CastToType() = TYP_DOUBLE;
            tree->gtType = TYP_DOUBLE;

            tree = gtNewCastNode(TYP_FLOAT, tree, TYP_FLOAT);

            return fgMorphTree(tree);
        }
        if (tree->gtFlags & GTF_UNSIGNED)
            return fgMorphCastIntoHelper(tree, CORINFO_HELP_ULNG2DBL, oper);
        return fgMorphCastIntoHelper(tree, CORINFO_HELP_LNG2DBL, oper);
    }
#endif //_TARGET_ARM_

#ifdef _TARGET_AMD64_
    // Do we have to do two step U4/8 -> R4/8 ?
    // Codegen supports the following conversion as one-step operation
    // a) Long -> R4/R8
    // b) U8 -> R8
    //
    // The following conversions are performed as two-step operations using above.
    // U4 -> R4/8 = U4-> Long -> R4/8
    // U8 -> R4   = U8 -> R8 -> R4
    else if ((tree->gtFlags & GTF_UNSIGNED) && varTypeIsFloating(dstType))
    {
        srcType = genUnsignedType(srcType);

        if (srcType == TYP_ULONG)
        {
            if (dstType == TYP_FLOAT)
            {
                // Codegen can handle U8 -> R8 conversion.
                // U8 -> R4 =  U8 -> R8 -> R4
                // - change the dsttype to double
                // - insert a cast from double to float
                // - recurse into the resulting tree
                tree->CastToType() = TYP_DOUBLE;
                tree->gtType = TYP_DOUBLE;
                tree = gtNewCastNode(TYP_FLOAT, tree, TYP_FLOAT);
                return fgMorphTree(tree);
            }
        }
        else if (srcType == TYP_UINT)
        {
            oper = gtNewCastNode(TYP_LONG, oper, TYP_LONG);
            oper->gtFlags |= (tree->gtFlags & (GTF_OVERFLOW|GTF_EXCEPT|GTF_UNSIGNED));
            tree->gtFlags &= ~GTF_UNSIGNED;
        }
    }
#endif // _TARGET_AMD64_

#ifdef _TARGET_X86_
    // Do we have to do two step U4/8 -> R4/8 ?
    else if ((tree->gtFlags & GTF_UNSIGNED) && varTypeIsFloating(dstType))
    {
        srcType = genUnsignedType(srcType);

        if (srcType == TYP_ULONG)
        {
            return fgMorphCastIntoHelper(tree, CORINFO_HELP_ULNG2DBL, oper);
        }
        else if (srcType == TYP_UINT)
        {
            oper = gtNewCastNode(TYP_LONG, oper, TYP_LONG);
            oper->gtFlags |= (tree->gtFlags & (GTF_OVERFLOW|GTF_EXCEPT|GTF_UNSIGNED));
            tree->gtFlags &= ~GTF_UNSIGNED;
        }
    }
#endif //_TARGET_XARCH_
    else if (varTypeIsGC(srcType) != varTypeIsGC(dstType))
    {
        // We are casting away GC information.  we would like to just
        // change the type to int, however this gives the emitter fits because
        // it believes the variable is a GC variable at the begining of the
        // instruction group, but is not turned non-gc by the code generator
        // we fix this by copying the GC pointer to a non-gc pointer temp.
        noway_assert(!varTypeIsGC(dstType) && "How can we have a cast to a GCRef here?");

        // We generate an assignment to an int and then do the cast from an int. With this we avoid
        // the gc problem and we allow casts to bytes, longs,  etc...
        unsigned lclNum = lvaGrabTemp(true DEBUGARG("Cast away GC"));
        oper->gtType = TYP_I_IMPL;
        GenTreePtr asg = gtNewTempAssign(lclNum, oper);
        oper->gtType = srcType;

        // do the real cast
        GenTreePtr cast = gtNewCastNode(tree->TypeGet(), gtNewLclvNode(lclNum, TYP_I_IMPL), dstType);

        // Generate the comma tree
        oper = gtNewOperNode(GT_COMMA, tree->TypeGet(), asg, cast);

        return fgMorphTree(oper);
    }

    // Look for narrowing casts ([u]long -> [u]int) and try to push them
    // down into the operand before morphing it.
    //
    // It doesn't matter if this is cast is from ulong or long (i.e. if
    // GTF_UNSIGNED is set) because the transformation is only applied to
    // overflow-insensitive narrowing casts, which always silently truncate.
    //
    // Note that casts from [u]long to small integer types are handled above.
    if ((srcType == TYP_LONG) &&
        ((dstType == TYP_INT) || (dstType == TYP_UINT)))
    {
        // As a special case, look for overflow-sensitive casts of an AND
        // expression, and see if the second operand is a small constant. Since
        // the result of an AND is bound by its smaller operand, it may be
        // possible to prove that the cast won't overflow, which will in turn
        // allow the cast's operand to be transformed.
        if (tree->gtOverflow() && (oper->OperGet() == GT_AND))
        {
            GenTreePtr andOp2 = oper->gtOp.gtOp2;

            // Special case to the special case: AND with a casted int.
            if ((andOp2->OperGet() == GT_CAST) &&
                (andOp2->gtCast.CastOp()->OperGet() == GT_CNS_INT))
            {
                // gtFoldExprConst will deal with whether the cast is signed or
                // unsigned, or overflow-sensitive.
                andOp2 = oper->gtOp.gtOp2 = gtFoldExprConst(andOp2);
            }

            // Look for a constant less than 2^{32} for a cast to uint, or less
            // than 2^{31} for a cast to int.
            int maxWidth = (dstType == TYP_UINT) ? 32 : 31;

            if ((andOp2->OperGet() == GT_CNS_NATIVELONG) &&
                ((andOp2->gtIntConCommon.LngValue() >> maxWidth) == 0))
            {
                // This cast can't overflow.
                tree->gtFlags &= ~(GTF_OVERFLOW | GTF_EXCEPT);
            }
        }

        // Only apply this transformation during global morph,
        // when neither the cast node nor the oper node may throw an exception
        // based on the upper 32 bits.
        //
        if (fgGlobalMorph                  &&
            !tree->gtOverflow()            &&
            !oper->gtOverflowEx())
        {
            // For these operations the lower 32 bits of the result only depends 
            // upon the lower 32 bits of the operands
            //
            if ( (oper->OperGet() == GT_ADD) ||
                 (oper->OperGet() == GT_MUL) ||
                 (oper->OperGet() == GT_AND) ||
                 (oper->OperGet() == GT_OR)  ||
                 (oper->OperGet() == GT_XOR)    )
            {
                DEBUG_DESTROY_NODE(tree);

                // Insert narrowing casts for op1 and op2
                oper->gtOp.gtOp1 = gtNewCastNode(TYP_INT, oper->gtOp.gtOp1, dstType);
                oper->gtOp.gtOp2 = gtNewCastNode(TYP_INT, oper->gtOp.gtOp2, dstType);

                // Clear the GT_MUL_64RSLT if it is set
                if  (oper->gtOper == GT_MUL && (oper->gtFlags & GTF_MUL_64RSLT))
                    oper->gtFlags &= ~GTF_MUL_64RSLT;

                // The operation now produces a 32-bit result.
                oper->gtType = TYP_INT;

                // Remorph the new tree as the casts that we added may be folded away.
                return fgMorphTree(oper);
            }
        }
    }

OPTIMIZECAST:
    noway_assert(tree->gtOper == GT_CAST);

    /* Morph the operand */
    tree->gtCast.CastOp() = oper = fgMorphTree(oper);

    /* Reset the call flag */
    tree->gtFlags &= ~GTF_CALL;

    /* unless we have an overflow cast, reset the except flag */
    if (!tree->gtOverflow())
        tree->gtFlags &= ~GTF_EXCEPT;

    /* Just in case new side effects were introduced */
    tree->gtFlags |= (oper->gtFlags & GTF_ALL_EFFECT);

    srcType = oper->TypeGet();

    /* if GTF_UNSIGNED is set then force srcType to an unsigned type */
    if (tree->gtFlags & GTF_UNSIGNED)
        srcType = genUnsignedType(srcType);

    srcSize = genTypeSize(srcType);

    if (!gtIsActiveCSE_Candidate(tree))     // tree cannot be a CSE candidate
    {
        /* See if we can discard the cast */
        if (varTypeIsIntegral(srcType) && varTypeIsIntegral(dstType))
        {
            if (srcType == dstType) // Certainly if they are identical it is pointless
                goto REMOVE_CAST;

            if (oper->OperGet() == GT_LCL_VAR && varTypeIsSmall(dstType))
            {
                unsigned    varNum = oper->gtLclVarCommon.gtLclNum;
                LclVarDsc * varDsc = &lvaTable[varNum];
                if (varDsc->TypeGet() == dstType && varDsc->lvNormalizeOnStore())
                    goto REMOVE_CAST;
            }

            bool  unsignedSrc = varTypeIsUnsigned(srcType);
            bool  unsignedDst = varTypeIsUnsigned(dstType);
            bool  signsDiffer = (unsignedSrc != unsignedDst);

            // For same sized casts with
            //    the same signs or non-overflow cast we discard them as well
            if (srcSize == dstSize)
            {
                /* This should have been handled above */
                noway_assert(varTypeIsGC(srcType) == varTypeIsGC(dstType));

                if (!signsDiffer)
                    goto REMOVE_CAST;

                if (!tree->gtOverflow())
                {
                    /* For small type casts, when necessary we force
                       the src operand to the dstType and allow the
                       implied load from memory to perform the casting */
                    if (varTypeIsSmall(srcType))
                    {
                        switch (oper->gtOper)
                        {
                        case GT_IND:
                        case GT_CLS_VAR:
                        case GT_LCL_FLD:
                        case GT_ARR_ELEM:
                            oper->gtType = dstType;
                            goto REMOVE_CAST;
                        default: break;
                        }
                    }
                    else
                        goto REMOVE_CAST;
                }
            }

            if (srcSize < dstSize)  // widening cast
            {
                // Keep any long casts
                if (dstSize == sizeof(int))
                {
                    // Only keep signed to unsigned widening cast with overflow check
                    if (!tree->gtOverflow() || !unsignedDst || unsignedSrc)
                        goto REMOVE_CAST;
                }

                // Casts from signed->unsigned can never overflow while widening

                if (unsignedSrc || !unsignedDst)
                    tree->gtFlags &= ~GTF_OVERFLOW;
            }
            else
            {
                // Try to narrow the operand of the cast and discard the cast
                // Note: Do not narrow a cast that is marked as a CSE
                // And do not narrow if the oper is marked as a CSE either
                //
                if  (!tree->gtOverflow()                  &&
                     !gtIsActiveCSE_Candidate(oper)       &&
                     (opts.compFlags & CLFLG_TREETRANS)   &&
                     optNarrowTree(oper, srcType, dstType, tree->gtVNPair, false))
                {
                    optNarrowTree(oper, srcType, dstType,  tree->gtVNPair, true);
                    
                    /* If oper is changed into a cast to TYP_INT, or to a GT_NOP, we may need to discard it */
                    if (oper->gtOper == GT_CAST && oper->CastToType() == genActualType(oper->CastFromType()))
                    {
                        oper = oper->gtCast.CastOp();
                    }
                    goto REMOVE_CAST;
                }
            }
        }
        
        switch (oper->gtOper)
        {
            /* If the operand is a constant, we'll fold it */
        case GT_CNS_INT:
        case GT_CNS_LNG:
        case GT_CNS_DBL:
        case GT_CNS_STR:
            {
                GenTreePtr oldTree = tree;

                tree = gtFoldExprConst(tree);    // This may not fold the constant (NaN ...)

                // Did we get a comma throw as a result of gtFoldExprConst?
                if ((oldTree != tree) && (oldTree->gtOper != GT_COMMA))
                {
                    noway_assert(fgIsCommaThrow(tree));
                    tree->gtOp.gtOp1 = fgMorphTree(tree->gtOp.gtOp1);
                    fgMorphTreeDone(tree);
                    return tree;
                }
                else if (tree->gtOper != GT_CAST)
                    return tree;

                noway_assert(tree->gtCast.CastOp() == oper); // unchanged
            }
            break;

        case GT_CAST:
            /* Check for two consecutive casts into the same dstType */
            if (!tree->gtOverflow())
            {
                var_types dstType2 = oper->CastToType();
                if (dstType == dstType2)
                    goto REMOVE_CAST;
            }
            break;

            /* If op1 is a mod node, mark it with the GTF_MOD_INT_RESULT flag
               so that the code generator will know not to convert the result
               of the idiv to a regpair */
        case GT_MOD:
            if (dstType == TYP_INT)
                tree->gtOp.gtOp1->gtFlags |= GTF_MOD_INT_RESULT;

                break;
        case GT_UMOD:
            if (dstType == TYP_UINT)
                tree->gtOp.gtOp1->gtFlags |= GTF_MOD_INT_RESULT;
                break;

        case GT_COMMA:
            // Check for cast of a GT_COMMA with a throw overflow
            // Bug 110829: Since this optimization will bash the types 
            // neither oper or commaOp2 can be CSE candidates
            if (fgIsCommaThrow(oper)  &&
                !gtIsActiveCSE_Candidate(oper))   // oper can not be a CSE candidate
            {
                GenTreePtr commaOp2 = oper->gtOp.gtOp2;

                if (!gtIsActiveCSE_Candidate(commaOp2))   // commaOp2 can not be a CSE candidate
                {
                   // need type of oper to be same as tree
                   if (tree->gtType == TYP_LONG)
                   {
                      commaOp2->ChangeOperConst(GT_CNS_NATIVELONG);
                      commaOp2->gtIntConCommon.SetLngValue(0);
                      /* Change the types of oper and commaOp2 to TYP_LONG */
                      oper->gtType = commaOp2->gtType = TYP_LONG;
                   }
                   else if (varTypeIsFloating(tree->gtType))
                   {
                      commaOp2->ChangeOperConst(GT_CNS_DBL);
                      commaOp2->gtDblCon.gtDconVal = 0.0;
                      // Change the types of oper and commaOp2
                      // X87 promotes everything to TYP_DOUBLE
                      // But other's are a little more precise
                      const var_types newTyp
#if FEATURE_X87_DOUBLES
                                             = TYP_DOUBLE;
#else // FEATURE_X87_DOUBLES
                                             = tree->gtType;
#endif // FEATURE_X87_DOUBLES
                      oper->gtType = commaOp2->gtType = newTyp;
                   }
                   else
                   {
                      commaOp2->ChangeOperConst(GT_CNS_INT);
                      commaOp2->gtIntCon.gtIconVal = 0;
                      /* Change the types of oper and commaOp2 to TYP_INT */
                      oper->gtType = commaOp2->gtType = TYP_INT;
                   }
                }

                if (vnStore != nullptr)
                {
                   fgValueNumberTreeConst(commaOp2);
                }

                /* Return the GT_COMMA node as the new tree */
                return oper;
            }
            break;

        default:
            break;
        } /* end switch (oper->gtOper) */
    }

    if (tree->gtOverflow())
        fgAddCodeRef(compCurBB, bbThrowIndex(compCurBB), SCK_OVERFLOW, fgPtrArgCntCur);

    return tree;

REMOVE_CAST:

    /* Here we've eliminated the cast, so just return it's operand */
    assert(!gtIsActiveCSE_Candidate(tree));     // tree cannot be a CSE candidate

    DEBUG_DESTROY_NODE(tree);
    return oper;
}
#ifdef _PREFAST_
#pragma warning(pop)
#endif

/*****************************************************************************
 *
 *  Perform an unwrap operation on a Proxy object
 */

GenTreePtr          Compiler::fgUnwrapProxy(GenTreePtr objRef)
{
    assert(info.compIsContextful  &&
           info.compUnwrapContextful &&
           impIsThis(objRef));

    CORINFO_EE_INFO * pInfo   = eeGetEEInfo();
    GenTreePtr        addTree;

    // Perform the unwrap:
    //
    //   This requires two extra indirections.
    //   We mark these indirections as 'invariant' and
    //   the CSE logic will hoist them when appropriate.
    //
    //  Note that each dereference is a GC pointer

    addTree = gtNewOperNode(GT_ADD, TYP_I_IMPL,
                            objRef,
                            gtNewIconNode(pInfo->offsetOfTransparentProxyRP, TYP_I_IMPL));

    objRef           = gtNewOperNode(GT_IND, TYP_REF, addTree);
    objRef->gtFlags |= GTF_IND_INVARIANT;

    addTree = gtNewOperNode(GT_ADD, TYP_I_IMPL,
                            objRef,
                            gtNewIconNode(pInfo->offsetOfRealProxyServer, TYP_I_IMPL));

    objRef           = gtNewOperNode(GT_IND, TYP_REF, addTree);
    objRef->gtFlags |= GTF_IND_INVARIANT;

    // objRef now hold the 'real this' reference (i.e. the unwrapped proxy)
    return objRef;
}

/*****************************************************************************
 *
 *  Morph an argument list; compute the pointer argument count in the process.
 *
 *  NOTE: This function can be called from any place in the JIT to perform re-morphing
 *  due to graph altering modifications such as copy / constant propagation
 */

unsigned UpdateGT_LISTFlags(GenTreePtr tree)
{
    assert(tree->gtOper == GT_LIST);

    unsigned flags = 0;
    if (tree->gtOp.gtOp2)
    {
        flags |= UpdateGT_LISTFlags(tree->gtOp.gtOp2);
    }

    flags |= (tree->gtOp.gtOp1->gtFlags & GTF_ALL_EFFECT);

    tree->gtFlags &= ~GTF_ALL_EFFECT;
    tree->gtFlags |= flags;

    return tree->gtFlags;
}

fgArgInfo::fgArgInfo(Compiler *  comp,  GenTreePtr  call, unsigned numArgs)
{
    compiler     = comp;
    callTree     = call;    assert(call->IsCall());
    argCount     = 0;       // filled in arg count, starts at zero
    nextSlotNum  = INIT_ARG_STACK_SLOT;
    stkLevel     = 0;
    argTableSize = numArgs; // the allocated table size
    argsComplete = false;
    argsSorted   = false;

    if (argTableSize == 0)
        argTable = NULL;
    else
        argTable = new(compiler, CMK_fgArgInfoPtrArr) fgArgTabEntryPtr[argTableSize];
 }

/*****************************************************************************
 *
 *  fgArgInfo Copy Constructor
 *
 *  This method needs to act like a copy constructor for fgArgInfo.
 *  The newCall needs to have its fgArgInfo initialized such that
 *  we have newCall that is an exact copy of the oldCall.
 *  We have to take care since the argument information
 *  in the argTable contains pointers that must point to the
 *  new arguments and not the old arguments.
 */
fgArgInfo::fgArgInfo(GenTreePtr  newCall, GenTreePtr  oldCall)
{
    assert(oldCall->IsCall());
    assert(newCall->IsCall());

    fgArgInfoPtr oldArgInfo = oldCall->gtCall.fgArgInfo;

    compiler     = oldArgInfo->compiler;;
    callTree     = newCall;  assert(newCall->IsCall());
    argCount     = 0;       // filled in arg count, starts at zero
    nextSlotNum  = INIT_ARG_STACK_SLOT;
    stkLevel     = oldArgInfo->stkLevel;
    argTableSize = oldArgInfo->argTableSize;
    argsComplete = false;
    argTable     = NULL;
    if (argTableSize > 0)
    {
        argTable = new(compiler, CMK_fgArgInfoPtrArr) fgArgTabEntryPtr[argTableSize];
        for (unsigned inx=0; inx<argTableSize; inx++)
        {
            argTable[inx] = NULL;
        }
    }

    assert(oldArgInfo->argsComplete);

    // We create local, artificial GenTreeArgLists that includes the gtCallObjp, if that exists, as first argument,
    // so we can iterate over these argument lists more uniformly.
    // Need to provide a temporary non-null first arguments to these constructors: if we use them, we'll replace them
    GenTreeArgList* newArgs;
    GenTreeArgList newArgObjp(newCall, newCall->gtCall.gtCallArgs);
    GenTreeArgList* oldArgs;
    GenTreeArgList oldArgObjp(oldCall, oldCall->gtCall.gtCallArgs);

    if (newCall->gtCall.gtCallObjp == NULL)
    {
        assert(oldCall->gtCall.gtCallObjp == NULL);
        newArgs = newCall->gtCall.gtCallArgs;
        oldArgs = oldCall->gtCall.gtCallArgs;
    }
    else
    {
        assert(oldCall->gtCall.gtCallObjp != NULL);
        newArgObjp.Current() = newCall->gtCall.gtCallArgs;
        newArgs = &newArgObjp;
        oldArgObjp.Current() = oldCall->gtCall.gtCallObjp;
        oldArgs = &oldArgObjp;
    }

    GenTreePtr          newCurr;
    GenTreePtr          oldCurr;
    GenTreeArgList*     newParent   = NULL;
    GenTreeArgList*     oldParent   = NULL;
    fgArgTabEntryPtr *  oldArgTable = oldArgInfo->argTable;
    bool                scanRegArgs = false;

    while (newArgs)
    {
        /* Get hold of the next argument values for the oldCall and newCall */

        newCurr = newArgs->Current();
        oldCurr = oldArgs->Current();
        if (newArgs != &newArgObjp)
        {
            newParent = newArgs;
            oldParent = oldArgs;
        }
        else
        {
            assert(newParent == NULL && oldParent == NULL);
        }
        newArgs = newArgs->Rest();
        oldArgs = oldArgs->Rest();

        fgArgTabEntryPtr oldArgTabEntry = NULL;
        fgArgTabEntryPtr newArgTabEntry = NULL;

        for (unsigned inx=0; inx<argTableSize; inx++)
        {
            oldArgTabEntry = oldArgTable[inx];

            if (oldArgTabEntry->parent == oldParent)
            {
                assert((oldParent == NULL) == (newParent == NULL));

                // We have found the matching "parent" field in oldArgTabEntry

                newArgTabEntry = new (compiler, CMK_fgArgInfo) fgArgTabEntry;

                // First block copy all fields
                //
                *newArgTabEntry = *oldArgTabEntry;

                // Then update all GenTreePtr fields in the newArgTabEntry
                //
                newArgTabEntry->parent = newParent;

                // The node field is likely to have been updated
                //  to point at a node in the gtCallLateArgs list
                //
                if (oldArgTabEntry->node == oldCurr)
                {
                    // node is not pointing into the gtCallLateArgs list
                    newArgTabEntry->node = newCurr;
                }
                else
                {
                    // node must be pointing into the gtCallLateArgs list
                    //
                    // We will fix this pointer up in the next loop
                    //
                    newArgTabEntry->node = NULL;  // For now we assign a NULL to this field

                    scanRegArgs = true;
                }

                // Now initialize the proper element in the argTable array
                //
                argTable[inx] = newArgTabEntry;
                break;
            }
        }
        // We should have found the matching oldArgTabEntry and created the newArgTabEntry
        //
        assert(newArgTabEntry != NULL);
    }

    if (scanRegArgs)
    {
        newArgs = newCall->gtCall.gtCallLateArgs;
        oldArgs = oldCall->gtCall.gtCallLateArgs;

        while (newArgs)
        {
            /* Get hold of the next argument values for the oldCall and newCall */

            assert(newArgs->IsList());

            newCurr = newArgs->Current();
            newArgs = newArgs->Rest();

            assert(oldArgs->IsList());

            oldCurr = oldArgs->Current();
            oldArgs = oldArgs->Rest();

            fgArgTabEntryPtr oldArgTabEntry = NULL;
            fgArgTabEntryPtr newArgTabEntry = NULL;

            for (unsigned inx=0; inx<argTableSize; inx++)
            {
                oldArgTabEntry = oldArgTable[inx];

                if (oldArgTabEntry->node == oldCurr)
                {
                    // We have found the matching "node" field in oldArgTabEntry

                    newArgTabEntry = argTable[inx];
                    assert(newArgTabEntry != NULL);

                    // update the "node" GenTreePtr fields in the newArgTabEntry
                    //
                    assert(newArgTabEntry->node == NULL);  // We previously assigned NULL to this field

                    newArgTabEntry->node = newCurr;
                    break;
                }
            }
        }
    }

    argCount     = oldArgInfo->argCount;
    nextSlotNum  = oldArgInfo->nextSlotNum;
    argsComplete = true;
    argsSorted   = true;
}

void fgArgInfo::AddArg(fgArgTabEntryPtr curArgTabEntry)
{
    assert(argCount < argTableSize);
    argTable[argCount] = curArgTabEntry;
    argCount++;
}

fgArgTabEntryPtr fgArgInfo::AddRegArg(unsigned    argNum,
                                      GenTreePtr  node,
                                      GenTreePtr  parent,
                                      regNumber   regNum,
                                      unsigned    numRegs,
                                      unsigned    alignment)
{
    fgArgTabEntryPtr curArgTabEntry = new(compiler, CMK_fgArgInfo) fgArgTabEntry;

    curArgTabEntry->argNum =            argNum;
    curArgTabEntry->node =              node;
    curArgTabEntry->parent =            parent;
    curArgTabEntry->regNum =            regNum;
    curArgTabEntry->slotNum =           0;
    curArgTabEntry->numRegs =           numRegs;
    curArgTabEntry->numSlots =          0;
    curArgTabEntry->alignment =         alignment;
    curArgTabEntry->lateArgInx =        (unsigned)-1;
    curArgTabEntry->tmpNum =            (unsigned)-1;
    curArgTabEntry->isSplit =           false;
    curArgTabEntry->isTmp =             false;
    curArgTabEntry->needTmp =           false;
    curArgTabEntry->needPlace =         false;
    curArgTabEntry->processed =         false;
    curArgTabEntry->isHfaRegArg =       false;
    curArgTabEntry->isBackFilled =      false;
    curArgTabEntry->isNonStandard =     false;

    AddArg(curArgTabEntry);
    return curArgTabEntry;
}

#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
fgArgTabEntryPtr fgArgInfo::AddRegArg(unsigned          argNum,
                                      GenTreePtr        node,
                                      GenTreePtr        parent,
                                      regNumber         regNum,
                                      unsigned          numRegs,
                                      unsigned          alignment,
                                      const bool        isStruct,
                                      const regNumber   otherRegNum,
                                      const SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR* const structDescPtr)
{
    fgArgTabEntryPtr curArgTabEntry = AddRegArg(argNum, node, parent, regNum, numRegs, alignment);
    assert(curArgTabEntry != nullptr);

    // The node of the ArgTabEntry could change after remorphing - it could be rewritten to a cpyblk or a
    // PlaceHolder node (in case of needed late argument, for example.)
    // This requires using of an extra flag. At creation time the state is right, so
    // and this assert enforces that.
    assert((varTypeIsStruct(node) && isStruct) || (!varTypeIsStruct(node) && !isStruct));
    curArgTabEntry->otherRegNum = otherRegNum;                       // Second reg for the struct
    curArgTabEntry->isStruct = isStruct;                             // is this a struct arg

    if (isStruct && structDescPtr != nullptr)
    {
        curArgTabEntry->structDesc.CopyFrom(*structDescPtr);
    }

    return curArgTabEntry;
}
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)

fgArgTabEntryPtr fgArgInfo::AddStkArg(unsigned    argNum,
                                      GenTreePtr  node,
                                      GenTreePtr  parent,
                                      unsigned    numSlots,
                                      unsigned    alignment
                                      FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY_ARG(const bool isStruct))
{
    fgArgTabEntryPtr curArgTabEntry = new(compiler, CMK_fgArgInfo) fgArgTabEntry;

    nextSlotNum = (unsigned)roundUp(nextSlotNum, alignment);

#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
    // The node of the ArgTabEntry could change after remorphing - it could be rewritten to a cpyblk or a
    // PlaceHolder node (in case of needed late argument, for example.)
    // This reqires using of an extra flag. At creation time the state is right, so
    // and this assert enforces that.
    assert((varTypeIsStruct(node) && isStruct) || (!varTypeIsStruct(node) && !isStruct));
    curArgTabEntry->isStruct = isStruct;                             // is this a struct arg
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)

    curArgTabEntry->argNum        = argNum;
    curArgTabEntry->node          = node;
    curArgTabEntry->parent        = parent;
    curArgTabEntry->regNum        = REG_STK;
    curArgTabEntry->slotNum       = nextSlotNum;
    curArgTabEntry->numRegs       = 0;
    curArgTabEntry->numSlots      = numSlots;
    curArgTabEntry->alignment     = alignment;
    curArgTabEntry->lateArgInx    = (unsigned) -1;
    curArgTabEntry->tmpNum        = (unsigned) -1;
    curArgTabEntry->isSplit       = false;
    curArgTabEntry->isTmp         = false;
    curArgTabEntry->needTmp       = false;
    curArgTabEntry->needPlace     = false;
    curArgTabEntry->processed     = false;
    curArgTabEntry->isHfaRegArg   = false;
    curArgTabEntry->isBackFilled  = false;
    curArgTabEntry->isNonStandard = false;

    AddArg(curArgTabEntry);

    nextSlotNum += numSlots;
    return curArgTabEntry;
}

void fgArgInfo::RemorphReset()
{
    nextSlotNum = INIT_ARG_STACK_SLOT;
}

fgArgTabEntry* fgArgInfo::RemorphRegArg(unsigned    argNum,
                                        GenTreePtr  node,
                                        GenTreePtr  parent,
                                        regNumber   regNum,
                                        unsigned    numRegs,
                                        unsigned    alignment)
{
    fgArgTabEntryPtr  curArgTabEntry = NULL;
    unsigned          regArgInx      = 0;
    unsigned          inx;

    for (inx=0; inx < argCount; inx++)
    {
        curArgTabEntry = argTable[inx];
        if (curArgTabEntry->argNum == argNum)
            break;

        bool isRegArg;
        GenTreePtr argx;
        if (curArgTabEntry->parent != NULL)
        {
            assert(curArgTabEntry->parent->IsList());
            argx     = curArgTabEntry->parent->Current();
            isRegArg = (argx->gtFlags & GTF_LATE_ARG) != 0;
        }
        else
        {
            argx     = curArgTabEntry->node;
            isRegArg = true;
        }

        if (isRegArg)
        {
            regArgInx++;
        }
    }
    // if this was a nonstandard arg the table is definitive
    if (curArgTabEntry->isNonStandard)
        regNum = curArgTabEntry->regNum;

    assert(curArgTabEntry->argNum    == argNum);
    assert(curArgTabEntry->regNum    == regNum);
    assert(curArgTabEntry->alignment == alignment);
    assert(curArgTabEntry->parent    == parent);

    if (curArgTabEntry->node != node)
    {
        GenTreePtr  argx     = NULL;
        unsigned    regIndex = 0;

        /* process the register argument list */
        for (GenTreeArgList* list = callTree->gtCall.gtCallLateArgs; list; (regIndex++, list = list->Rest()))
        {
            argx = list->Current();
            assert(!argx->IsArgPlaceHolderNode());  // No place holders nodes are in gtCallLateArgs;
            if (regIndex == regArgInx)
                break;
        }
        assert(regIndex == regArgInx);
        assert(regArgInx == curArgTabEntry->lateArgInx);

        if (curArgTabEntry->node != argx)
        {
            curArgTabEntry->node = argx;
        }
    }
    return curArgTabEntry;
}

void fgArgInfo::RemorphStkArg(unsigned    argNum,
                              GenTreePtr  node,
                              GenTreePtr  parent,
                              unsigned    numSlots,
                              unsigned    alignment)
{
    fgArgTabEntryPtr  curArgTabEntry = NULL;
    bool              isRegArg       = false;
    unsigned          regArgInx      = 0;
    GenTreePtr        argx;
    unsigned          inx;

    for (inx=0; inx < argCount; inx++)
    {
        curArgTabEntry = argTable[inx];

        if (curArgTabEntry->parent != NULL)
        {
            assert(curArgTabEntry->parent->IsList());
            argx     = curArgTabEntry->parent->Current();
            isRegArg = (argx->gtFlags & GTF_LATE_ARG) != 0;
        }
        else
        {
            argx     = curArgTabEntry->node;
            isRegArg = true;
        }

        if (curArgTabEntry->argNum == argNum)
            break;

        if (isRegArg)
            regArgInx++;
    }

    nextSlotNum = (unsigned) roundUp(nextSlotNum, alignment);

    assert(curArgTabEntry->argNum    == argNum);
    assert(curArgTabEntry->slotNum   == nextSlotNum);
    assert(curArgTabEntry->numSlots  == numSlots);
    assert(curArgTabEntry->alignment == alignment);
    assert(curArgTabEntry->parent    == parent);
    assert(parent->IsList());

#if FEATURE_FIXED_OUT_ARGS
    if (curArgTabEntry->node != node)
    {
        if (isRegArg)
        {
            GenTreePtr  argx     = NULL;
            unsigned    regIndex = 0;

            /* process the register argument list */
            for (GenTreeArgList * list = callTree->gtCall.gtCallLateArgs; list; list = list->Rest(), regIndex++)
            {
                argx = list->Current();
                assert(!argx->IsArgPlaceHolderNode());  // No place holders nodes are in gtCallLateArgs;
                if (regIndex == regArgInx)
                    break;
            }
            assert(regIndex == regArgInx);
            assert(regArgInx == curArgTabEntry->lateArgInx);

            if (curArgTabEntry->node != argx)
            {
                curArgTabEntry->node = argx;
            }
        }
        else
        {
            assert(parent->Current() == node);
            curArgTabEntry->node = node;
        }
    }
#else
    curArgTabEntry->node = node;
#endif

    nextSlotNum += numSlots;
}

void fgArgInfo::SplitArg(unsigned  argNum,
                         unsigned  numRegs,
                         unsigned  numSlots)
{
    fgArgTabEntryPtr  curArgTabEntry = NULL;
    assert(argNum < argCount);
    for (unsigned inx=0; inx < argCount; inx++)
    {
        curArgTabEntry = argTable[inx];
        if (curArgTabEntry->argNum == argNum)
            break;
    }

    assert(numRegs  > 0);
    assert(numSlots > 0);

    curArgTabEntry->isSplit  = true;
    curArgTabEntry->numRegs  = numRegs;
    curArgTabEntry->numSlots = numSlots;

    nextSlotNum += numSlots;
}

void fgArgInfo::EvalToTmp(unsigned    argNum,
                          unsigned    tmpNum,
                          GenTreePtr  newNode)
{
    fgArgTabEntryPtr  curArgTabEntry = NULL;
    assert(argNum < argCount);
    for (unsigned inx=0; inx < argCount; inx++)
    {
        curArgTabEntry = argTable[inx];
        if (curArgTabEntry->argNum == argNum)
            break;
    }
    assert(curArgTabEntry->parent->Current() == newNode);

    curArgTabEntry->node    = newNode;
    curArgTabEntry->tmpNum  = tmpNum;
    curArgTabEntry->isTmp   = true;
}

void fgArgInfo::ArgsComplete()
{
    bool hasStackArgs    = false;
    bool hasStructRegArg = false;

    for (unsigned curInx = 0; curInx < argCount; curInx++)
    {
        fgArgTabEntryPtr curArgTabEntry = argTable[curInx];
        assert(curArgTabEntry != NULL);
        GenTreePtr       argx           = curArgTabEntry->node;

#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
        // If this is a struct, mark it for needing a tempVar.
        // In the copyblk and store this should have minimal perf impact since 
        // the local vars where we copy/store to already exist and the logic for temp 
        // var will not create a new one if it creates a tempVar from another tempVar.
        // (Debugging through the code, there was no new copy of data created, neither a new tempVar.)
        // The need for this arise from Lower::LowerArg. 
        // In case of copyblk and store operation, the NewPutArg method will 
        // not be invoked and the struct will not be loaded to be passed in
        // registers or by value on the stack.
        if (varTypeIsStruct(argx) FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY( || curArgTabEntry->isStruct))
        {
            curArgTabEntry->needTmp = true;
        }
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)

        if (curArgTabEntry->regNum == REG_STK)
        {
            hasStackArgs = true;
#if !FEATURE_FIXED_OUT_ARGS
            // On x86 we use push instructions to pass arguments:
            //   The non-register arguments are evaluated and pushed in order
            //   and they are never evaluated into temps
            //
            continue;
#endif
        }
        else // we have a register argument, next we look for a struct type.
        {
            if (varTypeIsStruct(argx)
                FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY( || curArgTabEntry->isStruct))
            {
                hasStructRegArg = true;
            }
        }

        /* If the argument tree contains an assignment (GTF_ASG) then the argument and
           and every earlier argument (except constants) must be evaluated into temps
           since there may be other arguments that follow and they may use the value being assigned.

           EXAMPLE: ArgTab is "a, a=5, a"
                    -> when we see the second arg "a=5"
                       we know the first two arguments "a, a=5" have to be evaluated into temps

           For the case of an assignment, we only know that there exist some assignment someplace
           in the tree.  We don't know what is being assigned so we are very conservative here
           and assume that any local variable could have been assigned.
         */

        if (argx->gtFlags & GTF_ASG)
        {
            // If this is not the only argument, or it's a copyblk, or it already evaluates the expression to
            // a tmp, then we need a temp in the late arg list.
            if ((argCount > 1) || argx->OperIsCopyBlkOp()
#ifdef FEATURE_FIXED_OUT_ARGS
                || curArgTabEntry->isTmp   // I protect this by "FEATURE_FIXED_OUT_ARGS" to preserve the property
                                           // that we only have late non-register args when that feature is on.
#endif // FEATURE_FIXED_OUT_ARGS
                )
            {
                curArgTabEntry->needTmp = true;
            }

            // For all previous arguments, unless they are a simple constant
            //  we require that they be evaluated into temps
            for (unsigned prevInx = 0; prevInx < curInx; prevInx++)
            {
                fgArgTabEntryPtr prevArgTabEntry  = argTable[prevInx];
                assert(prevArgTabEntry->argNum < curArgTabEntry->argNum);

                assert(prevArgTabEntry->node);
                if (prevArgTabEntry->node->gtOper != GT_CNS_INT)
                {
                    prevArgTabEntry->needTmp = true;
                }
            }
        }

#if FEATURE_FIXED_OUT_ARGS
        // Like calls, if this argument has a tree that will do an inline throw,
        // a call to a jit helper, then we need to treat it like a call (but only
        // if there are/were any stack args).
        // This means unnesting, sorting, etc.  Technically this is overly
        // conservative, but I want to avoid as much special-case debug-only code
        // as possible, so leveraging the GTF_CALL flag is the easiest.
        if (!(argx->gtFlags & GTF_CALL) &&
            (argx->gtFlags & GTF_EXCEPT) &&
            (argCount > 1) &&
            compiler->opts.compDbgCode &&
            (compiler->fgWalkTreePre(&argx, Compiler::fgChkThrowCB) == Compiler::WALK_ABORT))
        {
            for (unsigned otherInx = 0; otherInx < argCount; otherInx++)
            {
                if (otherInx == curInx)
                    continue;

                if (argTable[otherInx]->regNum == REG_STK)
                {
                    argx->gtFlags |= GTF_CALL;
                    break;
                }
            }
        }
#endif // FEATURE_FIXED_OUT_ARGS

        /* If it contains a call (GTF_CALL) then itself and everything before the call
           with a GLOB_EFFECT must eval to temp (this is because everything with SIDE_EFFECT
           has to be kept in the right order since we will move the call to the first position)

           For calls we don't have to be quite as conservative as we are with an assignment
           since the call won't be modifying any non-address taken LclVars.
         */

        if (argx->gtFlags & GTF_CALL)
        {
            if (argCount > 1)       // If this is not the only argument
            {
                curArgTabEntry->needTmp = true;
            }
            else if (varTypeIsFloating(argx->TypeGet()) && (argx->OperGet() == GT_CALL))
            {
                // Spill all arguments that are floating point calls
                curArgTabEntry->needTmp = true;
            }

            // All previous arguments may need to be evaluated into temps
            for (unsigned prevInx = 0; prevInx < curInx; prevInx++)
            {
                fgArgTabEntryPtr prevArgTabEntry  = argTable[prevInx];
                assert(prevArgTabEntry->argNum < curArgTabEntry->argNum);
                assert(prevArgTabEntry->node);

                // For all previous arguments, if they have any GTF_ALL_EFFECT
                //  we require that they be evaluated into a temp
                if ((prevArgTabEntry->node->gtFlags & GTF_ALL_EFFECT) != 0)
                {
                    prevArgTabEntry->needTmp = true;
                }
#if FEATURE_FIXED_OUT_ARGS
                // Or, if they are stored into the FIXED_OUT_ARG area
                // we require that they be moved to the gtCallLateArgs
                // and replaced with a placeholder node
                else if (prevArgTabEntry->regNum == REG_STK)
                {
                    prevArgTabEntry->needPlace = true;
                }
#endif
            }
        }

#ifndef LEGACY_BACKEND
        // For RyuJIT backend we will expand a Multireg arg into a GT_LIST 
        // with multiple indirections, so here we consider spilling it into a tmp LclVar.
        //
        // Note that Arm32 is a LEGACY_BACKEND and it defines FEATURE_MULTIREG_ARGS
        // so we skip this for ARM32 until it is ported to use RyuJIT backend
        //
#if FEATURE_MULTIREG_ARGS
        if ((argx->TypeGet() == TYP_STRUCT) &&
            (curArgTabEntry->numRegs > 1)   && 
            (curArgTabEntry->needTmp == false))
        {           
            if ((argx->gtFlags & GTF_PERSISTENT_SIDE_EFFECTS) != 0)
            {
                // Spill multireg struct arguments that have Assignments or Calls embedded in them
                curArgTabEntry->needTmp = true;
            }
            else
            {
                // We call gtPrepareCost to measure the cost of evaluating this tree
                compiler->gtPrepareCost(argx);

                if (argx->gtCostEx > (6 * IND_COST_EX))
                {
                    // Spill multireg struct arguments that are expensive to evaluate twice
                    curArgTabEntry->needTmp = true;
                }
            }
        }
#endif // FEATURE_MULTIREG_ARGS
#endif // LEGACY_BACKEND
    }


    // We only care because we can't spill structs and qmarks involve a lot of spilling, but
    // if we don't have qmarks, then it doesn't matter.
    // So check for Qmark's globally once here, instead of inside the loop.
    //
    const bool hasStructRegArgWeCareAbout = (hasStructRegArg && compiler->compQmarkUsed);

#if FEATURE_FIXED_OUT_ARGS

    // For Arm/x64 we only care because we can't reorder a register
    // argument that uses GT_LCLHEAP.  This is an optimization to
    // save a check inside the below loop.
    //
    const bool hasStackArgsWeCareAbout = (hasStackArgs && compiler->compLocallocUsed);

#else

    const bool hasStackArgsWeCareAbout = hasStackArgs;

#endif // FEATURE_FIXED_OUT_ARGS

    // If we have any stack args we have to force the evaluation
    // of any arguments passed in registers that might throw an exception
    //
    // Technically we only a required to handle the following two cases:
    //     a GT_IND with GTF_IND_RNGCHK (only on x86) or
    //     a GT_LCLHEAP node that allocates stuff on the stack
    //
    if (hasStackArgsWeCareAbout || hasStructRegArgWeCareAbout)
    {
        for (unsigned curInx = 0; curInx < argCount; curInx++)
        {
            fgArgTabEntryPtr curArgTabEntry  = argTable[curInx];        assert(curArgTabEntry != NULL);
            GenTreePtr       argx            = curArgTabEntry->node;

            // Examine the register args that are currently not marked needTmp
            //
            if (!curArgTabEntry->needTmp && (curArgTabEntry->regNum != REG_STK))
            {
                if (hasStackArgsWeCareAbout)
                {
#if !FEATURE_FIXED_OUT_ARGS
                    // On x86 we previously recorded a stack depth of zero when
                    // morphing the register arguments of any GT_IND with a GTF_IND_RNGCHK flag
                    // Thus we can not reorder the argument after any stack based argument
                    // (Note that GT_LCLHEAP sets the GTF_EXCEPT flag so we don't need to
                    // check for it explicitly
                    //
                    if (argx->gtFlags & GTF_EXCEPT)
                    {
                        curArgTabEntry->needTmp = true;
                        continue;
                    }
#else
                    // For Arm/X64 we can't reorder a register argument that uses a GT_LCLHEAP
                    //
                    if (argx->gtFlags & GTF_EXCEPT)
                    {
                        assert(compiler->compLocallocUsed);

                        // Returns WALK_ABORT if a GT_LCLHEAP node is encountered in the argx tree
                        //
                        if (compiler->fgWalkTreePre(&argx, Compiler::fgChkLocAllocCB) == Compiler::WALK_ABORT)
                        {
                            curArgTabEntry->needTmp = true;
                            continue;
                        }
                    }
#endif
                }
                if (hasStructRegArgWeCareAbout)
                {
                    // Returns true if a GT_QMARK node is encountered in the argx tree
                    //
                    if (compiler->fgWalkTreePre(&argx, Compiler::fgChkQmarkCB) == Compiler::WALK_ABORT)
                    {
                        curArgTabEntry->needTmp = true;
                        continue;
                    }
                }
            }
        }
    }

    argsComplete = true;
}

void fgArgInfo::SortArgs()
{
    assert(argsComplete == true);

    /* Shuffle the arguments around before we build the gtCallLateArgs list.
       The idea is to move all "simple" arguments like constants and local vars
       to the end of the table, and move the complex arguments towards the beginning
       of the table. This will help prevent registers from being spilled by
       allowing us to evaluate the more complex arguments before the simpler arguments.
       The argTable ends up looking like:
           +------------------------------------+  <--- argTable[argCount - 1]
           |          constants                 |
           +------------------------------------+
           |    local var / local field         |
           +------------------------------------+
           | remaining arguments sorted by cost |
           +------------------------------------+
           | temps (argTable[].needTmp = true)  |
           +------------------------------------+
           |  args with calls (GTF_CALL)        |
           +------------------------------------+  <--- argTable[0]
     */

#ifdef DEBUG
    if (compiler->verbose)
    {
        printf("\nSorting the arguments:\n");
    }
#endif

    /* Set the beginning and end for the new argument table */
    unsigned curInx;
    int      regCount      = 0;
    unsigned begTab        = 0;
    unsigned endTab        = argCount - 1;
    unsigned argsRemaining = argCount;

    // First take care of arguments that are constants.
    // [We use a backward iterator pattern]
    //
    curInx = argCount;
    do {
        curInx--;

        fgArgTabEntryPtr curArgTabEntry = argTable[curInx];

        if (curArgTabEntry->regNum != REG_STK)
            regCount++;

        // Skip any already processed args
        //
        if (!curArgTabEntry->processed)
        {
            GenTreePtr   argx = curArgTabEntry->node;

            // put constants at the end of the table
            //
            if (argx->gtOper == GT_CNS_INT)
            {
                noway_assert(curInx <= endTab);

                curArgTabEntry->processed = true;

                // place curArgTabEntry at the endTab position by performing a swap
                //
                if (curInx != endTab)
                {
                    argTable[curInx] = argTable[endTab];
                    argTable[endTab] = curArgTabEntry;
                }

                endTab--;
                argsRemaining--;
            }
        }
    }  while (curInx > 0);

    if (argsRemaining > 0)
    {
        // Next take care of arguments that are calls.
        // [We use a forward iterator pattern]
        //
        for (curInx = begTab; curInx <= endTab; curInx++)
        {
            fgArgTabEntryPtr curArgTabEntry = argTable[curInx];

            // Skip any already processed args
            //
            if (!curArgTabEntry->processed)
            {
                GenTreePtr   argx = curArgTabEntry->node;

                // put calls at the beginning of the table
                //
                if (argx->gtFlags & GTF_CALL)
                {
                    curArgTabEntry->processed = true;

                    // place curArgTabEntry at the begTab position by performing a swap
                    //
                    if (curInx != begTab)
                    {
                        argTable[curInx] = argTable[begTab];
                        argTable[begTab] = curArgTabEntry;
                    }

                    begTab++;
                    argsRemaining--;
                }
            }
        }
    }

    if (argsRemaining > 0)
    {
        // Next take care arguments that are temps.
        // These temps come before the arguments that are
        // ordinary local vars or local fields
        // since this will give them a better chance to become
        // enregistered into their actual argument register.
        // [We use a forward iterator pattern]
        //
        for (curInx = begTab; curInx <= endTab; curInx++)
        {
            fgArgTabEntryPtr curArgTabEntry = argTable[curInx];

            // Skip any already processed args
            //
            if (!curArgTabEntry->processed)
            {
                if (curArgTabEntry->needTmp)
                {
                    curArgTabEntry->processed = true;

                    // place curArgTabEntry at the begTab position by performing a swap
                    //
                    if (curInx != begTab)
                    {
                        argTable[curInx] = argTable[begTab];
                        argTable[begTab] = curArgTabEntry;
                    }

                    begTab++;
                    argsRemaining--;
                }
            }
        }
    }

    if (argsRemaining > 0)
    {
        // Next take care of local var and local field arguments.
        // These are moved towards the end of the argument evaluation.
        // [We use a backward iterator pattern]
        //
        curInx = endTab + 1;
        do {
            curInx--;

            fgArgTabEntryPtr curArgTabEntry = argTable[curInx];

            // Skip any already processed args
            //
            if (!curArgTabEntry->processed)
            {
                GenTreePtr   argx = curArgTabEntry->node;

                if ((argx->gtOper == GT_LCL_VAR) || (argx->gtOper == GT_LCL_FLD))
                {
                    noway_assert(curInx <= endTab);

                    curArgTabEntry->processed = true;

                    // place curArgTabEntry at the endTab position by performing a swap
                    //
                    if (curInx != endTab)
                    {
                        argTable[curInx] = argTable[endTab];
                        argTable[endTab] = curArgTabEntry;
                    }

                    endTab--;
                    argsRemaining--;
                }
            }
        } while (curInx > begTab);
    }

    // Finally, take care of all the remaining arguments.
    // Note that we fill in one arg at a time using a while loop.
    bool costsPrepared = false; // Only prepare tree costs once, the first time through this loop
    while (argsRemaining > 0)
    {
        /* Find the most expensive arg remaining and evaluate it next */

        fgArgTabEntryPtr expensiveArgTabEntry = NULL;
        unsigned         expensiveArg         = UINT_MAX;
        unsigned         expensiveArgCost     = 0;

        // [We use a forward iterator pattern]
        //
        for (curInx = begTab; curInx <= endTab; curInx++)
        {
            fgArgTabEntryPtr curArgTabEntry = argTable[curInx];

            // Skip any already processed args
            //
            if (!curArgTabEntry->processed)
            {
                GenTreePtr  argx = curArgTabEntry->node;

                // We should have already handled these kinds of args
                assert (argx->gtOper != GT_LCL_VAR);
                assert (argx->gtOper != GT_LCL_FLD);
                assert (argx->gtOper != GT_CNS_INT);

                // This arg should either have no persistent side effects or be the last one in our table
                // assert(((argx->gtFlags & GTF_PERSISTENT_SIDE_EFFECTS) == 0) || (curInx == (argCount-1)));

                if (argsRemaining == 1)
                {
                    // This is the last arg to place
                    expensiveArg         = curInx;
                    expensiveArgTabEntry = curArgTabEntry;
                    assert(begTab == endTab);
                    break;
                }
                else
                {
                    if (!costsPrepared)
                    {
                        /* We call gtPrepareCost to measure the cost of evaluating this tree */
                        compiler->gtPrepareCost(argx);
                    }

                    if (argx->gtCostEx > expensiveArgCost)
                    {
                        // Remember this arg as the most expensive one that we have yet seen
                        expensiveArgCost     = argx->gtCostEx;
                        expensiveArg         = curInx;
                        expensiveArgTabEntry = curArgTabEntry;
                    }
                }
            }
        }

        noway_assert(expensiveArg != UINT_MAX);

        // put the most expensive arg towards the beginning of the table

        expensiveArgTabEntry->processed = true;

        // place expensiveArgTabEntry at the begTab position by performing a swap
        //
        if (expensiveArg != begTab)
        {
            argTable[expensiveArg] = argTable[begTab];
            argTable[begTab]       = expensiveArgTabEntry;
        }

        begTab++;
        argsRemaining--;

        costsPrepared = true; // If we have more expensive arguments, don't re-evaluate the tree cost on the next loop
    }

    // The table should now be completely filled and thus begTab should now be adjacent to endTab
    // and regArgsRemaining should be zero
    assert(begTab == (endTab + 1));
    assert(argsRemaining == 0);

#if !FEATURE_FIXED_OUT_ARGS
    // Finally build the regArgList
    //
    callTree->gtCall.regArgList = NULL;
    callTree->gtCall.regArgListCount = regCount;

    unsigned regInx = 0;
    for (curInx = 0; curInx < argCount; curInx++)
    {
        fgArgTabEntryPtr curArgTabEntry = argTable[curInx];

        if (curArgTabEntry->regNum != REG_STK)
        {
            // Encode the argument register in the register mask
            //
            callTree->gtCall.regArgList[regInx] = curArgTabEntry->regNum;
            regInx++;
        }
    }
#endif // !FEATURE_FIXED_OUT_ARGS

    argsSorted = true;
}

//------------------------------------------------------------------------------
// fgMakeTmpArgNode : This function creates a tmp var only if needed.
//                    We need this to be done in order to enforce ordering
//                    of the evaluation of arguments.
//
// Arguments:
//    tmpVarNum  - the var num which we clone into the newly created temp var.
//
// Return Value:
//    the newly created temp var tree. 

GenTreePtr    Compiler::fgMakeTmpArgNode(unsigned tmpVarNum
                                         FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY_ARG(const bool passedInRegisters))
{
    LclVarDsc *  varDsc = &lvaTable[tmpVarNum];
    assert(varDsc->lvIsTemp);
    var_types  type = varDsc->TypeGet();

    // Create a copy of the temp to go into the late argument list
    GenTreePtr arg = gtNewLclvNode(tmpVarNum, type);
    GenTreePtr addrNode = nullptr;

    if (varTypeIsStruct(type))
    {

#if defined(_TARGET_AMD64_) || defined(_TARGET_ARM64_)

#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING

        arg->gtFlags |= GTF_DONT_CSE;

        // If it is passed in registers, don't get the address of the var. Make it a
        // field instead. It will be loaded in registers with putarg_reg tree in lower.
        if (passedInRegisters)
        {
            arg->ChangeOper(GT_LCL_FLD);
            arg->gtType = type;
        }
        else
        {
            arg = gtNewOperNode(GT_ADDR, type, arg);
            addrNode = arg;
        }

#else // !FEATURE_UNIX_AMD64_STRUCT_PASSING 

        unsigned structSize = lvaLclExactSize(tmpVarNum);

        switch (structSize)
        {
        case 1: type = TYP_BYTE;  break;
        case 2: type = TYP_SHORT; break;
#if defined (_TARGET_AMD64_)
        case 4: type = TYP_INT;   break;
#elif defined(_TARGET_ARM64_)
        case 3:
        case 4: type = TYP_INT;   break;
        case 5: 
        case 6:
        case 7: type = TYP_I_IMPL; break;
#endif // defined (_TARGET_ARM64_)
        case 8: 
            switch (*lvaGetGcLayout(tmpVarNum))
            {
            case TYPE_GC_NONE:
                type = TYP_I_IMPL;
                break;
            case TYPE_GC_REF:
                type = TYP_REF;
                break;
            case TYPE_GC_BYREF:
                type = TYP_BYREF;
                break;
            default:
                unreached();
            }
            break;
        default:
            break;
        }

        // If we didn't change the type of the struct, it means
        // its structure doesn't support to be passed directly through a
        // register, so we need to pass a pointer to the destination where
        // where we copied the struct to.
        if (type == varDsc->TypeGet())
        {
#if FEATURE_MULTIREG_ARGS
#ifdef _TARGET_ARM64_
            assert(varTypeIsStruct(type));
            if (varDsc->lvIsMultiregStruct())
            {
                // ToDo-ARM64: Consider using:  arg->ChangeOper(GT_LCL_FLD);
                // as that is how FEATURE_UNIX_AMD64_STRUCT_PASSING works.
                // Create a GT_OBJ for the argument 
                // This will be passed by value in two registers
                arg = gtNewOperNode(GT_ADDR, TYP_BYREF, arg);
                addrNode = arg;

                // Create an Obj of the temp to use it as a call argument.
                arg = gtNewObjNode(lvaGetStruct(tmpVarNum), arg);
            }
            else
#endif // _TARGET_ARM64_
#endif // FEATURE_MULTIREG_ARGS
            {
                arg = gtNewOperNode(GT_ADDR, TYP_I_IMPL, arg);
                addrNode = arg;
            }
        }
        else // type was changed from a struct to a scalar type
        {
            arg->ChangeOper(GT_LCL_FLD);
            arg->gtType = type;
        }
#endif // !FEATURE_UNIX_AMD64_STRUCT_PASSING

#else // not (_TARGET_AMD64_ or _TARGET_ARM64_)

        // other targets, we pass the struct by value 
        assert(varTypeIsStruct(type));

        arg = gtNewOperNode(GT_ADDR, TYP_BYREF, arg);
        addrNode = arg;

        // Get a new Obj node temp to use it as a call argument
        arg = gtNewObjNode(lvaGetStruct(tmpVarNum), arg);
        arg->gtFlags |= GTF_EXCEPT;

#endif  // not (_TARGET_AMD64_ or _TARGET_ARM64_)

    } // (varTypeIsStruct(type))

    if (addrNode != nullptr)
    {
        assert(addrNode->gtOper == GT_ADDR);

        // This will prevent this LclVar from being optimized away
        lvaSetVarAddrExposed(tmpVarNum); 

        // the child of a GT_ADDR is required to have this flag set
        addrNode->gtOp.gtOp1->gtFlags |= GTF_DONT_CSE;
    }

    return arg;
}

void fgArgInfo::EvalArgsToTemps()
{
    assert(argsSorted == true);

    unsigned regArgInx = 0;
    // Now go through the argument table and perform the necessary evaluation into temps
    GenTreeArgList* tmpRegArgNext = NULL;
    for (unsigned curInx = 0; curInx < argCount; curInx++)
    {
        fgArgTabEntryPtr curArgTabEntry = argTable[curInx];

        GenTreePtr  argx     = curArgTabEntry->node;
        GenTreePtr  setupArg = NULL;
        GenTreePtr  defArg;

#if !FEATURE_FIXED_OUT_ARGS
        // Only ever set for FEATURE_FIXED_OUT_ARGS
        assert(curArgTabEntry->needPlace == false);

        // On x86 and other archs that use push instructions to pass arguments:
        //   Only the register arguments need to be replaced with placeholder nodes.
        //   Stacked arguments are evaluated and pushed (or stored into the stack) in order.
        //
        if (curArgTabEntry->regNum == REG_STK) 
            continue;
#endif

        if (curArgTabEntry->needTmp)
        {
            unsigned tmpVarNum;

            if (curArgTabEntry->isTmp == true)
            {
                // Create a copy of the temp to go into the late argument list
                tmpVarNum = curArgTabEntry->tmpNum;
                defArg = compiler->fgMakeTmpArgNode(
                    tmpVarNum
                    FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY_ARG(argTable[curInx]->structDesc.passedInRegisters));

                // mark the original node as a late argument
                argx->gtFlags |= GTF_LATE_ARG;
            }
            else
            {
                // Create a temp assignment for the argument
                //  Put the temp in the gtCallLateArgs list
#ifdef DEBUG
                if (compiler->verbose)
                {
                    printf("Argument with 'side effect'...\n");
                    compiler->gtDispTree(argx);
                }
#endif

#if defined(_TARGET_AMD64_) && !defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                noway_assert(argx->gtType != TYP_STRUCT);
#endif

                tmpVarNum = compiler->lvaGrabTemp(true DEBUGARG("argument with side effect"));
                if (argx->gtOper == GT_MKREFANY)
                {
                    // For GT_MKREFANY, typically the actual struct copying does
                    // not have any side-effects and can be delayed. So instead
                    // of using a temp for the whole struct, we can just use a temp
                    // for operand that that has a side-effect
                    GenTreePtr operand;
                    if ((argx->gtOp.gtOp2->gtFlags & GTF_ALL_EFFECT) == 0)
                    {
                        operand = argx->gtOp.gtOp1;

                        // In the early argument evaluation, place an assignment to the temp
                        // from the source operand of the mkrefany
                        setupArg = compiler->gtNewTempAssign(tmpVarNum, operand);

                        // Replace the operand for the mkrefany with the new temp.
                        argx->gtOp.gtOp1 = compiler->gtNewLclvNode(tmpVarNum, operand->TypeGet());
                    }
                    else if ((argx->gtOp.gtOp1->gtFlags & GTF_ALL_EFFECT) == 0)
                    {
                        operand = argx->gtOp.gtOp2;

                        // In the early argument evaluation, place an assignment to the temp
                        // from the source operand of the mkrefany
                        setupArg = compiler->gtNewTempAssign(tmpVarNum, operand);

                        // Replace the operand for the mkrefany with the new temp.
                        argx->gtOp.gtOp2 = compiler->gtNewLclvNode(tmpVarNum, operand->TypeGet());
                    }
                }

                if (setupArg != NULL)
                {
                    // Now keep the mkrefany for the late argument list
                    defArg = argx;

                    // Clear the side-effect flags because now both op1 and op2 have no side-effects
                    defArg->gtFlags &= ~GTF_ALL_EFFECT;
                }
                else
                {
                    setupArg = compiler->gtNewTempAssign(tmpVarNum, argx);

#ifndef LEGACY_BACKEND
                    if (compiler->fgOrder == Compiler::FGOrderLinear)
                    {
                        // We'll reference this temporary variable just once
                        // when we perform the function call after
                        // setting up this argument.
                        LclVarDsc* varDsc = compiler->lvaTable + tmpVarNum;
                        varDsc->lvRefCnt = 1;
                    }
#endif // !LEGACY_BACKEND

                    if (setupArg->OperIsCopyBlkOp())
                        setupArg = compiler->fgMorphCopyBlock(setupArg);

                    /* Create a copy of the temp to go to the late argument list */
                    defArg = compiler->gtNewLclvNode(tmpVarNum, genActualType(argx->gtType));

                    curArgTabEntry->isTmp   = true;
                    curArgTabEntry->tmpNum  = tmpVarNum;

#ifdef _TARGET_ARM_
                    // Previously we might have thought the local was promoted, and thus the 'COPYBLK'
                    // might have left holes in the used registers (see
                    // fgAddSkippedRegsInPromotedStructArg).
                    // Too bad we're not that smart for these intermediate temps...
                    if (isValidIntArgReg(curArgTabEntry->regNum) && (curArgTabEntry->numRegs > 1))
                    {
                        regNumber argReg = curArgTabEntry->regNum;
                        regMaskTP allUsedRegs = genRegMask(curArgTabEntry->regNum);
                        for (unsigned i = 1; i < curArgTabEntry->numRegs; i++)
                        {
                            argReg = genRegArgNext(argReg);
                            allUsedRegs |= genRegMask(argReg);
                        }
                        callTree->gtCall.gtCallRegUsedMask |= allUsedRegs;
                    }
#endif // _TARGET_ARM_
                }

                /* mark the assignment as a late argument */
                setupArg->gtFlags |= GTF_LATE_ARG;

#ifdef DEBUG
                if (compiler->verbose)
                {
                    printf("\n  Evaluate to a temp:\n");
                    compiler->gtDispTree(setupArg);
                }
#endif
            }
        }
        else // curArgTabEntry->needTmp == false
        {
            //   On x86 -
            //      Only register args are replaced with placeholder nodes
            //      and the stack based arguments are evaluated and pushed in order.
            //
            //   On Arm/x64 - When needTmp is false and needPlace is false,
            //      the non-register arguments are evaluated and stored in order.
            //      When needPlace is true we have a nested call that comes after
            //      this argument so we have to replace it in the gtCallArgs list
            //      (the initial argument evaluation list) with a placeholder.
            //
            if ((curArgTabEntry->regNum == REG_STK) && (curArgTabEntry->needPlace == false))
                continue;

            /* No temp needed - move the whole node to the gtCallLateArgs list */

            /* The argument is deferred and put in the late argument list */

            defArg = argx;

            // Create a placeholder node to put in its place in gtCallLateArgs.

            // For a struct type we also need to record the class handle of the arg.
            CORINFO_CLASS_HANDLE clsHnd = NO_CLASS_HANDLE;

#if defined(_TARGET_AMD64_) && !defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)

            // All structs are either passed (and retyped) as integral types, OR they
            // are passed by reference.
            noway_assert(argx->gtType != TYP_STRUCT);

#else // !defined(_TARGET_AMD64_) || defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)

            if (varTypeIsStruct(defArg))
            {
                // Need a temp to walk any GT_COMMA nodes when searching for the clsHnd
                GenTreePtr  defArgTmp = defArg;

                // The GT_OBJ may be be a child of a GT_COMMA.
                while (defArgTmp->gtOper == GT_COMMA)
                {
                    defArgTmp = defArgTmp->gtOp.gtOp2;
                }
                assert(varTypeIsStruct(defArgTmp));

                // We handle two opcodes: GT_MKREFANY and GT_OBJ.
                if (defArgTmp->gtOper == GT_MKREFANY)
                {
                    clsHnd = compiler->impGetRefAnyClass();
                }
                else if (defArgTmp->gtOper == GT_OBJ)
                {
                    clsHnd = defArgTmp->AsObj()->gtClass;
                }
                else
                {
                    BADCODE("Unhandled struct argument tree in fgMorphArgs");
                }
        }

#endif // !(defined(_TARGET_AMD64_) && !defined(FEATURE_UNIX_AMD64_STRUCT_PASSING))

            setupArg = compiler->gtNewArgPlaceHolderNode(defArg->gtType, clsHnd);

            /* mark the placeholder node as a late argument */
            setupArg->gtFlags |= GTF_LATE_ARG;

#ifdef DEBUG
            if (compiler->verbose)
            {
                if (curArgTabEntry->regNum == REG_STK)
                {
                    printf("Deferred stack argument :\n");
                }
                else
                {
                    printf("Deferred argument ('%s'):\n", getRegName(curArgTabEntry->regNum));
                }

                compiler->gtDispTree(argx);
                printf("Replaced with placeholder node:\n");
                compiler->gtDispTree(setupArg);
            }
#endif
        }

        if (setupArg != NULL)
        {
            if (curArgTabEntry->parent)
            {
                GenTreePtr  parent = curArgTabEntry->parent;
                /* a normal argument from the list */
                noway_assert(parent->IsList());
                noway_assert(parent->gtOp.gtOp1 == argx);

                parent->gtOp.gtOp1 = setupArg;
            }
            else
            {
                /* must be the gtCallObjp */
                noway_assert(callTree->gtCall.gtCallObjp == argx);

                callTree->gtCall.gtCallObjp = setupArg;
            }
        }

        /* deferred arg goes into the late argument list */

        if (tmpRegArgNext == NULL)
        {
            tmpRegArgNext = compiler->gtNewArgList(defArg);
            callTree->gtCall.gtCallLateArgs = tmpRegArgNext;
        }
        else
        {
            noway_assert(tmpRegArgNext->IsList());
            noway_assert(tmpRegArgNext->Current());
            tmpRegArgNext->gtOp.gtOp2 = compiler->gtNewArgList(defArg);
            tmpRegArgNext = tmpRegArgNext->Rest();
        }

        curArgTabEntry->node       = defArg;
        curArgTabEntry->lateArgInx = regArgInx++;
    }

#ifdef DEBUG
    if (compiler->verbose)
    {
        printf("\nShuffled argument table:    ");
        for (unsigned curInx = 0; curInx < argCount; curInx++)
        {
            fgArgTabEntryPtr curArgTabEntry = argTable[curInx];

            if (curArgTabEntry->regNum != REG_STK)
            {
                printf("%s ", getRegName( curArgTabEntry->regNum ));
            }
        }
        printf("\n");
    }
#endif
}

void fgArgInfo::RecordStkLevel(unsigned stkLvl)
{
    assert(!IsUninitialized(stkLvl));
    this->stkLevel = stkLvl;
}

unsigned fgArgInfo::RetrieveStkLevel()
{
    assert(!IsUninitialized(stkLevel));
    return stkLevel;
}

// Return a conservative estimate of the stack size in bytes.
// It will be used only on the intercepted-for-host code path to copy the arguments.
int Compiler::fgEstimateCallStackSize(GenTreeCall* call)
{

    int numArgs = 0;
    for (GenTreeArgList* args = call->gtCallArgs; args; args = args->Rest())
    {
        numArgs++;
    }

    int numStkArgs;
    if (numArgs > MAX_REG_ARG)
        numStkArgs = numArgs - MAX_REG_ARG;
    else
        numStkArgs = 0;

    return numStkArgs * REGSIZE_BYTES;
}

//------------------------------------------------------------------------------
// fgMakeMultiUse : If the node is a local, clone it and increase the ref count
//                  otherwise insert a comma form temp
//
// Arguments:
//    ppTree  - a pointer to the child node we will be replacing with the comma expression that
//              evaluates ppTree to a temp and returns the result
//
// Return Value:
//    A fresh GT_LCL_VAR node referencing the temp which has not been used 
//
// Assumption:
//    The result tree MUST be added to the tree structure since the ref counts are
//    already incremented.

GenTree* Compiler::fgMakeMultiUse(GenTree** pOp)
{
    GenTree* tree = *pOp;
    if (tree->IsLocal())
    {
        auto result = gtClone(tree);
        if (lvaLocalVarRefCounted)
        {
            lvaTable[tree->gtLclVarCommon.gtLclNum].incRefCnts(compCurBB->getBBWeight(this), this);
        }
        return result;
    }
    else
    {
        GenTree* result =  fgInsertCommaFormTemp(pOp);

        // At this point, *pOp is GT_COMMA(GT_ASG(V01, *pOp), V01) and result = V01
        // Therefore, the ref count has to be incremented 3 times for *pOp and result, if result will
        // be added by the caller.
        if (lvaLocalVarRefCounted)
        {
            lvaTable[result->gtLclVarCommon.gtLclNum].incRefCnts(compCurBB->getBBWeight(this), this);
            lvaTable[result->gtLclVarCommon.gtLclNum].incRefCnts(compCurBB->getBBWeight(this), this);
            lvaTable[result->gtLclVarCommon.gtLclNum].incRefCnts(compCurBB->getBBWeight(this), this);
        }

        return result;
    }
}


//------------------------------------------------------------------------------
// fgInsertCommaFormTemp: Create a new temporary variable to hold the result of *ppTree,
//                        and replace *ppTree with comma(asg(newLcl, *ppTree), newLcl)
//
// Arguments:
//    ppTree     - a pointer to the child node we will be replacing with the comma expression that
//                 evaluates ppTree to a temp and returns the result
//
//    structType - value type handle if the temp created is of TYP_STRUCT.
//
// Return Value:
//    A fresh GT_LCL_VAR node referencing the temp which has not been used 
//

GenTree*   Compiler::fgInsertCommaFormTemp(GenTree** ppTree, CORINFO_CLASS_HANDLE structType /*= nullptr*/)
{
    GenTree* subTree = *ppTree;

    unsigned lclNum = lvaGrabTemp(true DEBUGARG("fgInsertCommaFormTemp is creating a new local variable"));
   
    if (varTypeIsStruct(subTree))
    {
        assert(structType != nullptr);
        lvaSetStruct(lclNum, structType, false);
    }

    // If subTree->TypeGet() == TYP_STRUCT, gtNewTempAssign() will create a GT_COPYBLK tree.
    // The type of GT_COPYBLK is TYP_VOID.  Therefore, we should use subTree->TypeGet() for
    // setting type of lcl vars created.
    GenTree* asg = gtNewTempAssign(lclNum, subTree);

    GenTree* load = new (this, GT_LCL_VAR) GenTreeLclVar(subTree->TypeGet(), lclNum, BAD_IL_OFFSET);
    
    GenTree* comma = gtNewOperNode(GT_COMMA, subTree->TypeGet(), asg, load);

    *ppTree = comma;

    return new (this, GT_LCL_VAR) GenTreeLclVar(subTree->TypeGet(), lclNum, BAD_IL_OFFSET);
}


//------------------------------------------------------------------------
// fgMorphArgs: Walk and transform (morph) the arguments of a call
//
// Arguments:
//    callNode - the call for which we are doing the argument morphing
//
// Return Value:
//    Like most morph methods, this method returns the morphed node,
//    though in this case there are currently no scenarios where the
//    node itself is re-created.
//
// Notes:
//    This method is even less idempotent than most morph methods.
//    That is, it makes changes that should not be redone. It uses the existence
//    of gtCallLateArgs (the late arguments list) to determine if it has
//    already done that work.
//
//    The first time it is called (i.e. during global morphing), this method
//    computes the "late arguments". This is when it determines which arguments
//    need to be evaluated to temps prior to the main argument setup, and which
//    can be directly evaluated into the argument location. It also creates a
//    second argument list (gtCallLateArgs) that does the final placement of the
//    arguments, e.g. into registers or onto the stack.
//
//    The "non-late arguments", aka the gtCallArgs, are doing the in-order
//    evaluation of the arguments that might have side-effects, such as embedded
//    assignments, calls or possible throws. In these cases, it and earlier
//    arguments must be evaluated to temps.
//
//    On targets with a fixed outgoing argument area (FEATURE_FIXED_OUT_ARGS),
//    if we have any nested calls, we need to defer the copying of the argument
//    into the fixed argument area until after the call. If the argument did not
//    otherwise need to be computed into a temp, it is moved to gtCallLateArgs and
//    replaced in the "early" arg list (gtCallArgs) with a placeholder node.

#ifdef _PREFAST_
#pragma warning(push)
#pragma warning(disable:21000) // Suppress PREFast warning about overly large function
#endif
GenTreeCall* Compiler::fgMorphArgs(GenTreeCall* callNode)
{
    GenTreeCall* call = callNode->AsCall();

    GenTreePtr      args;
    GenTreePtr      argx;

    unsigned        flagsSummary  = 0;
    unsigned        genPtrArgCntSav = fgPtrArgCntCur;

    unsigned        argIndex      = 0;

    unsigned        intArgRegNum  = 0;
    unsigned        fltArgRegNum  = 0;

    regMaskTP       argSkippedRegMask    = RBM_NONE;

#if defined(_TARGET_ARM_) || defined(_TARGET_AMD64_)
    regMaskTP       fltArgSkippedRegMask = RBM_NONE;
#endif

#if defined(_TARGET_X86_)
    unsigned        maxRegArgs    = MAX_REG_ARG;  // X86: non-const, must be calculated
#else
    const unsigned  maxRegArgs    = MAX_REG_ARG;  // other arch: fixed constant number 
#endif 

    unsigned        argSlots          = 0;
    unsigned        nonRegPassedStructSlots = 0;
    bool            lateArgsComputed  = (call->gtCallLateArgs != nullptr);
    bool            callHasRetBuffArg = call->HasRetBufArg();

#ifndef _TARGET_X86_    // i.e. _TARGET_AMD64_ or _TARGET_ARM_
    bool            callIsVararg      = call->IsVarargs();
#endif

    bool hasNonStandardArg = false;
#ifndef LEGACY_BACKEND
    // data structure for keeping track of non-standard args we insert
    // (args that have a special meaning and are not passed following the normal
    // calling convention or even in the normal arg regs.
    struct NonStandardArg
    {
        regNumber reg;
        GenTree*  node;
    };

    ArrayStack<NonStandardArg> nonStandardArgs(this, 2);
#endif // !LEGACY_BACKEND

    // Process the late arguments (which were determined by a previous caller).
    // Do this before resetting fgPtrArgCntCur as fgMorphTree(call->gtCallLateArgs)
    // may need to refer to it.
    if  (lateArgsComputed)
    {
        // We need to reMorph the gtCallLateArgs early since that is what triggers
        // the expression folding and we need to have the final folded gtCallLateArgs
        // available when we call RemorphRegArg so that we correctly update the fgArgInfo
        // with the folded tree that represents the final optimized argument nodes.
        //
        // However if a range-check needs to be generated for any of these late
        // arguments we also need to "know" what the stack depth will be when we generate
        // code to branch to the throw range check failure block as that is part of the
        // GC information contract for that block.
        //
        // Since the late arguments are evaluated last we have pushed all of the
        // other arguments on the stack before we evaluate these late arguments,
        // so we record the stack depth on the first morph call when lateArgsComputed
        // was false (via RecordStkLevel) and then retrieve that value here (via RetrieveStkLevel)
        //
        unsigned callStkLevel = call->fgArgInfo->RetrieveStkLevel();
        fgPtrArgCntCur += callStkLevel;
        call->gtCallLateArgs = fgMorphTree(call->gtCallLateArgs)->AsArgList();
        flagsSummary |= call->gtCallLateArgs->gtFlags;
        fgPtrArgCntCur -= callStkLevel;
        assert(call->fgArgInfo != nullptr);
        call->fgArgInfo->RemorphReset();
    }
    else
    {
        // First we need to count the args
        unsigned numArgs = 0;
        if (call->gtCallObjp)
            numArgs++;
        for (args = call->gtCallArgs; (args != nullptr); args = args->gtOp.gtOp2)
        {
            numArgs++;
        }


        // insert nonstandard args (outside the calling convention)

#if !defined(LEGACY_BACKEND) && !defined(_TARGET_X86_)
        // TODO-X86-CQ: Currently RyuJIT/x86 passes args on the stack, so this is not needed.
        // If/when we change that, the following code needs to be changed to correctly support the (TBD) managed calling
        // convention for x86/SSE.
        if (!lateArgsComputed)
        {
            if (call->IsUnmanaged() && !opts.ShouldUsePInvokeHelpers())
            {
                assert(!call->gtCallCookie);
                // Add a conservative estimate of the stack size in a special parameter (r11) at the call site.
                // It will be used only on the intercepted-for-host code path to copy the arguments.             

                GenTree* cns = new (this, GT_CNS_INT) GenTreeIntCon(TYP_I_IMPL, fgEstimateCallStackSize(call));
                call->gtCallArgs = gtNewListNode(cns, call->gtCallArgs);
                NonStandardArg nsa = {REG_PINVOKE_COOKIE_PARAM, cns};
                numArgs++;

                nonStandardArgs.Push(nsa);
            }
            else if (call->IsVirtualStub() &&
                     (call->gtCallType == CT_INDIRECT) &&
                     !call->IsTailCallViaHelper())
            {
                // indirect VSD stubs need the base of the indirection cell to be 
                // passed in addition.  At this point that is the value in gtCallAddr.
                // The actual call target will be derived from gtCallAddr in call 
                // lowering.

                // If it is a VSD call getting dispatched via tail call helper,
                // fgMorphTailCall() would materialize stub addr as an additional
                // parameter added to the original arg list and hence no need to 
                // add as a non-standard arg.
                
                GenTree* arg = call->gtCallAddr;
                if (arg->OperIsLocal())
                {
                    arg = gtClone(arg, true);
                }
                else
                {
                    call->gtCallAddr = fgInsertCommaFormTemp(&arg);
                    call->gtFlags |= GTF_ASG;
                }
                noway_assert(arg != nullptr);
            
                // And push the stub address onto the list of arguments
                call->gtCallArgs = gtNewListNode(arg, call->gtCallArgs);
                numArgs++;

                NonStandardArg nsa = {REG_VIRTUAL_STUB_PARAM, arg};
            
                nonStandardArgs.Push(nsa);
            }
            else if (call->gtCallType == CT_INDIRECT && call->gtCallCookie)
            {
                assert(!call->IsUnmanaged());

                // put cookie into R11
                GenTree* arg = call->gtCallCookie;
                noway_assert(arg != nullptr);
                call->gtCallCookie = nullptr;

                call->gtCallArgs = gtNewListNode(arg, call->gtCallArgs);
                numArgs++;

                NonStandardArg nsa = {REG_PINVOKE_COOKIE_PARAM, arg};
            
                nonStandardArgs.Push(nsa);

                // put destination into R10
                arg = gtClone(call->gtCallAddr, true);
                call->gtCallArgs = gtNewListNode(arg, call->gtCallArgs);
                numArgs++;

                NonStandardArg nsa2 = {REG_PINVOKE_TARGET_PARAM, arg};
                nonStandardArgs.Push(nsa2);

                // finally change this call to a helper call
                call->gtCallType = CT_HELPER;
                call->gtCallMethHnd  = eeFindHelper(CORINFO_HELP_PINVOKE_CALLI);
            }
        }
#endif // !defined(LEGACY_BACKEND) && !defined(_TARGET_X86_)

        // Allocate the fgArgInfo for the call node;
        //
        call->fgArgInfo = new (this, CMK_Unknown) fgArgInfo(this, call, numArgs);
    }


    fgFixupStructReturn(call);

    /* First we morph the argument subtrees ('this' pointer, arguments, etc.).
     * During the first call to fgMorphArgs we also record the
     * information about late arguments we have in 'fgArgInfo'.
     * This information is used later to contruct the gtCallLateArgs */

    /* Process the 'this' argument value, if present */

    argx = call->gtCallObjp;

    if  (argx)
    {
        argx = fgMorphTree(argx);
        call->gtCallObjp = argx;
        flagsSummary |= argx->gtFlags;

        assert(call->gtCallType == CT_USER_FUNC ||
               call->gtCallType == CT_INDIRECT);

        assert(argIndex == 0);

        /* We must fill in or update the argInfo table */

        if  (!lateArgsComputed)
        {
            assert(varTypeIsGC(call->gtCallObjp->gtType) ||
                   (call->gtCallObjp->gtType == TYP_I_IMPL));

            /* this is a register argument - put it in the table */
            call->fgArgInfo->AddRegArg(argIndex,
                                       argx, 
                                       NULL, 
                                       genMapIntRegArgNumToRegNum(intArgRegNum),
                                       1, 
                                       1
#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
                                       , false,
                                       REG_STK,
                                       nullptr
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING
                );
        }
        else
        {
            /* this is a register argument - possibly update it in the table */
            call->fgArgInfo->RemorphRegArg(argIndex, argx, NULL, genMapIntRegArgNumToRegNum(intArgRegNum), 1, 1);
        }
        // this can't be a struct.
        assert(argx->gtType != TYP_STRUCT);

        // FIXME: Issue #4025 Why do we need floating type for 'this' argument
        /* Increment the argument register count and argument index */
        if (!varTypeIsFloating(argx->gtType) || opts.compUseSoftFP)
        {
            intArgRegNum++;
#if defined(_TARGET_AMD64_) && !defined(UNIX_AMD64_ABI)
            fltArgSkippedRegMask |= genMapArgNumToRegMask(fltArgRegNum, TYP_FLOAT);
            fltArgRegNum++;
#endif
        }
        else
        {
            fltArgRegNum++;
#if defined(_TARGET_AMD64_) && !defined(UNIX_AMD64_ABI)
            argSkippedRegMask |= genMapArgNumToRegMask(intArgRegNum, TYP_I_IMPL);
            intArgRegNum++;
#endif
        }
        argIndex++;
        argSlots++;
    }

#ifdef _TARGET_X86_
    // Compute the maximum number of arguments that can be passed in registers.
    // For X86 we handle the varargs and unmanaged calling conventions

    if  (call->gtFlags & GTF_CALL_POP_ARGS)
    {
        noway_assert(intArgRegNum < MAX_REG_ARG);
        // No more register arguments for varargs (CALL_POP_ARGS)
        maxRegArgs = intArgRegNum;

        // Add in the ret buff arg
        if (callHasRetBuffArg)
            maxRegArgs++;
    }

#if INLINE_NDIRECT
    if (call->IsUnmanaged())
    {
        noway_assert(intArgRegNum == 0);

        if (call->gtCallMoreFlags & GTF_CALL_M_UNMGD_THISCALL)
        {
            noway_assert(call->gtCallArgs->gtOp.gtOp1->TypeGet() == TYP_I_IMPL ||
                         call->gtCallArgs->gtOp.gtOp1->TypeGet() == TYP_BYREF ||
                         call->gtCallArgs->gtOp.gtOp1->gtOper == GT_NOP); // the arg was already morphed to a register (fgMorph called twice)
            maxRegArgs = 1;
        }
        else
        {
            maxRegArgs = 0;
        }

        // Add in the ret buff arg
        if (callHasRetBuffArg)
            maxRegArgs++;
    }
#endif // INLINE_NDIRECT
#endif // _TARGET_X86_

    /* Morph the user arguments */

#if defined(_TARGET_ARM_)

    // The ARM ABI has a concept of back-filling of floating-point argument registers, according
    // to the "Procedure Call Standard for the ARM Architecture" document, especially
    // section 6.1.2.3 "Parameter passing". Back-filling is where floating-point argument N+1 can
    // appear in a lower-numbered register than floating point argument N. That is, argument
    // register allocation is not strictly increasing. To support this, we need to keep track of unused
    // floating-point argument registers that we can back-fill. We only support 4-byte float and
    // 8-byte double types, and one to four element HFAs composed of these types. With this, we will
    // only back-fill single registers, since there is no way with these types to create
    // an alignment hole greater than one register. However, there can be up to 3 back-fill slots
    // available (with 16 FP argument registers). Consider this code:
    //
    // struct HFA { float x, y, z; }; // a three element HFA
    // void bar(float a1,   // passed in f0
    //          double a2,  // passed in f2/f3; skip f1 for alignment
    //          HFA a3,     // passed in f4/f5/f6
    //          double a4,  // passed in f8/f9; skip f7 for alignment. NOTE: it doesn't fit in the f1 back-fill slot
    //          HFA a5,     // passed in f10/f11/f12
    //          double a6,  // passed in f14/f15; skip f13 for alignment. NOTE: it doesn't fit in the f1 or f7 back-fill slots
    //          float a7,   // passed in f1 (back-filled)
    //          float a8,   // passed in f7 (back-filled)
    //          float a9,   // passed in f13 (back-filled)
    //          float a10)  // passed on the stack in [OutArg+0]
    //
    // Note that if we ever support FP types with larger alignment requirements, then there could
    // be more than single register back-fills.
    //
    // Once we assign a floating-pointer register to the stack, they all must be on the stack.
    // See "Procedure Call Standard for the ARM Architecture", section 6.1.2.3, "The back-filling
    // continues only so long as no VFP CPRC has been allocated to a slot on the stack."
    // We set anyFloatStackArgs to true when a floating-point argument has been assigned to the stack
    // and prevent any additional floating-point arguments from going in registers.

    bool anyFloatStackArgs = false;

#endif // _TARGET_ARM_

#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
    bool nonRegPassableStruct = false;
    SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR structDesc;
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING

    bool hasStructArgument     = false;   // @TODO-ARM64-UNIX: Eemove this bool during a future refactoring 
    bool hasMultiregStructArgs = false;
    for (args = call->gtCallArgs; args; args = args->gtOp.gtOp2)
    {
        GenTreePtr * parentArgx = &args->gtOp.gtOp1;

#if FEATURE_MULTIREG_ARGS
        if (!hasStructArgument)
        {
            hasStructArgument = varTypeIsStruct(args->gtOp.gtOp1);
        }
#endif // FEATURE_MULTIREG_ARGS

        argx = fgMorphTree(*parentArgx);
        *parentArgx = argx;
        flagsSummary |= argx->gtFlags;

        assert(args->IsList());
        assert(argx == args->Current());

        /* Change the node to TYP_I_IMPL so we don't report GC info
         * NOTE: We deferred this from the importer because of the inliner */

        if (argx->IsVarAddr())
            argx->gtType = TYP_I_IMPL;

        bool passUsingFloatRegs;
        unsigned argAlign = 1;

#ifdef _TARGET_ARM_
        var_types hfaType = GetHfaType(argx);
        bool isHfaArg = varTypeIsFloating(hfaType);
#endif // _TARGET_ARM_

        unsigned             size         = 0;
        CORINFO_CLASS_HANDLE copyBlkClass = NULL;
        bool                 isRegArg = false;

        fgArgTabEntryPtr argEntry = NULL;

        if (lateArgsComputed)
        {
            argEntry = gtArgEntryByArgNum(call, argIndex);
        }

#ifdef _TARGET_ARM_

        bool passUsingIntRegs;
        if (lateArgsComputed)
        {
            passUsingFloatRegs = isValidFloatArgReg(argEntry->regNum);
            passUsingIntRegs   = isValidIntArgReg(argEntry->regNum);
        }
        else
        {
            passUsingFloatRegs = !callIsVararg && (isHfaArg || varTypeIsFloating(argx)) && !opts.compUseSoftFP;
            passUsingIntRegs   =  passUsingFloatRegs ? false : (intArgRegNum < MAX_REG_ARG);
        }

        GenTreePtr curArg = argx;
        // If late args have already been computed, use the node in the argument table.
        if (argEntry != NULL && argEntry->isTmp)
        {
            curArg = argEntry->node;
        }

        // We don't use the "size" return value from InferOpSizeAlign().
        codeGen->InferOpSizeAlign(curArg, &argAlign);

        argAlign = roundUp(argAlign, TARGET_POINTER_SIZE);
        argAlign /= TARGET_POINTER_SIZE;

        if (argAlign == 2)
        {
            if (passUsingFloatRegs)
            {
                if (fltArgRegNum % 2 == 1)
                {
                    fltArgSkippedRegMask |= genMapArgNumToRegMask(fltArgRegNum, TYP_FLOAT);
                    fltArgRegNum ++;
                }
            }
            else if (passUsingIntRegs)
            {
                if (intArgRegNum % 2 == 1)
                {
                    argSkippedRegMask |= genMapArgNumToRegMask(intArgRegNum, TYP_I_IMPL);
                    intArgRegNum ++;
                }
            }

            if (argSlots % 2 == 1)
            {
                argSlots ++;
            }
        }

#elif defined(_TARGET_ARM64_)

        // TODO-ARM64-NYI: HFA/HVA
        if (lateArgsComputed)
        {
            passUsingFloatRegs = isValidFloatArgReg(argEntry->regNum);
        }
        else
        {
            passUsingFloatRegs = !callIsVararg && varTypeIsFloating(argx);
        }

#elif defined(_TARGET_AMD64_)
#if defined(UNIX_AMD64_ABI)        
        if (lateArgsComputed)
        {
            passUsingFloatRegs = isValidFloatArgReg(argEntry->regNum);
        }
        else
        {
            passUsingFloatRegs = varTypeIsFloating(argx);
        }
        bool passUsingIntRegs;
        passUsingIntRegs = passUsingFloatRegs ? false : (intArgRegNum < MAX_REG_ARG);
#else // !UNIX_AMD64_ABI
        passUsingFloatRegs = varTypeIsFloating(argx);
#endif // !UNIX_AMD64_ABI
#elif defined(_TARGET_X86_)

        passUsingFloatRegs = false;

#else
    #error Unsupported or unset target architecture
#endif // _TARGET_*

        bool         isBackFilled     = false;
        unsigned     nextFltArgRegNum = fltArgRegNum;  // This is the next floating-point argument register number to use
        var_types    structBaseType   = TYP_STRUCT;

#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
        unsigned int structFloatRegs = 0;
        unsigned int structIntRegs = 0;
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
        bool isStructArg = varTypeIsStruct(argx);

        if (lateArgsComputed)
        {
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
            // Get the struct description for the already completed struct argument.
            fgArgTabEntryPtr fgEntryPtr = gtArgEntryByNode(call, argx);
            assert(fgEntryPtr != nullptr);

            // As described in few other places, this can happen when the argx was morphed 
            // into an arg setup node - COPYBLK. The COPYBLK has always a type of void.
            // In such case the fgArgTabEntry keeps track of whether the original node (before morphing)
            // was a struct and the struct classification. 
            isStructArg = fgEntryPtr->isStruct;

            if (isStructArg)
            {
                structDesc.CopyFrom(fgEntryPtr->structDesc);
            }
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)

            assert(argEntry != NULL);
            if (argEntry->IsBackFilled())
            {
                isRegArg = true;
                size = argEntry->numRegs;
                nextFltArgRegNum = genMapFloatRegNumToRegArgNum(argEntry->regNum);
                assert(size == 1);
                isBackFilled = true;
            }
            else if (argEntry->regNum == REG_STK)
            {
                isRegArg = false;
                assert(argEntry->numRegs == 0);
                size = argEntry->numSlots;
            }
            else
            {
                isRegArg = true;
                assert(argEntry->numRegs > 0);
                size = argEntry->numRegs + argEntry->numSlots;
            }

            // This size has now been computed
            assert(size != 0);
        }
        else
        {
            //
            // Figure out the size of the argument. This is either in number of registers, or number of register-sized
            // stack slots, or both if the argument is split between the registers and the stack.
            //

            if (argx->IsArgPlaceHolderNode() || (!isStructArg))
            {
#if   defined(_TARGET_AMD64_)
#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
                if (!isStructArg)
                {
                    size = 1; // On AMD64, all primitives fit in a single (64-bit) 'slot'
                }
                else
                {
                    size = (unsigned)(roundUp(info.compCompHnd->getClassSize(argx->gtArgPlace.gtArgPlaceClsHnd), TARGET_POINTER_SIZE)) / TARGET_POINTER_SIZE;
                    eeGetSystemVAmd64PassStructInRegisterDescriptor(argx->gtArgPlace.gtArgPlaceClsHnd, &structDesc);
                    if (size > 1)
                    {
                        hasMultiregStructArgs = true;
                    }
                }
#else // !FEATURE_UNIX_AMD64_STRUCT_PASSING
                size = 1; // On AMD64, all primitives fit in a single (64-bit) 'slot'
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING
#elif defined(_TARGET_ARM64_)    
                if (isStructArg)
                {
                    // Structs are either passed in 1 or 2 (64-bit) slots
                    size = (unsigned)(roundUp(info.compCompHnd->getClassSize(argx->gtArgPlace.gtArgPlaceClsHnd), TARGET_POINTER_SIZE)) / TARGET_POINTER_SIZE;
                    if (size > 2)
                    {
                        size = 1;  // Large structs are passed by reference (to a copy)
                    }
                    else if (size == 2)
                    {
                        hasMultiregStructArgs = true;
                    }
                    // Note that there are some additional rules for size=2 structs,
                    // (i.e they cannot be split betwen registers and the stack)
                }
                else
                {
                    size = 1; // On ARM64, all primitive types fit in a single (64-bit) 'slot'
                }
#elif defined(_TARGET_ARM_)
                if (isStructArg)
                {
                    size = (unsigned)(roundUp(info.compCompHnd->getClassSize(argx->gtArgPlace.gtArgPlaceClsHnd), TARGET_POINTER_SIZE)) / TARGET_POINTER_SIZE;
                }
                else
                {
                    // The typical case
                    size = genTypeStSz(argx->gtType);
                }
#elif defined(_TARGET_X86_)
                size = genTypeStSz(argx->gtType);
#else 
#error Unsupported or unset target architecture
#endif // _TARGET_XXX_
            }
#ifdef _TARGET_ARM_
            else if (isHfaArg)
            {
                size = GetHfaSlots(argx);
            }
#endif
            else // struct type
            {
                // We handle two opcodes: GT_MKREFANY and GT_OBJ
                if (argx->gtOper == GT_MKREFANY)
                {
                    if (varTypeIsStruct(argx))
                    {
                        isStructArg = true;
                    }
#ifdef _TARGET_AMD64_
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                    if (varTypeIsStruct(argx))
                    {
                        size = info.compCompHnd->getClassSize(impGetRefAnyClass());
                        unsigned roundupSize = (unsigned)roundUp(size, TARGET_POINTER_SIZE);
                        size = roundupSize / TARGET_POINTER_SIZE;
                        eeGetSystemVAmd64PassStructInRegisterDescriptor(impGetRefAnyClass(), &structDesc);
                    }
                    else
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                    {
                        size = 1;
                    }
#else
                    size = 2;
#endif
                }
                else
                {
                    // GT_OBJ case
                    GenTreePtr   argObj         = argx;
                    GenTreePtr*  parentOfArgObj = parentArgx;

                    assert(args->IsList());
                    assert(argx == args->Current());

                    /* The GT_OBJ may be be a child of a GT_COMMA */
                    while (argObj->gtOper == GT_COMMA)
                    {
                        parentOfArgObj = &argObj->gtOp.gtOp2;
                        argObj         = argObj->gtOp.gtOp2;
                    }

                    if (argObj->gtOper != GT_OBJ)
                        BADCODE("illegal argument tree in fgMorphArgs");

                    CORINFO_CLASS_HANDLE objClass = argObj->gtObj.gtClass;
#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
                    eeGetSystemVAmd64PassStructInRegisterDescriptor(objClass, &structDesc);
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING

                    unsigned originalSize = info.compCompHnd->getClassSize(objClass);
                    originalSize = (originalSize == 0 ? TARGET_POINTER_SIZE : originalSize);
                    unsigned roundupSize  = (unsigned)roundUp(originalSize, TARGET_POINTER_SIZE);
#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
                    // On System V OS-es a struct is never passed by reference.
                    // It is either passed by value on the stack or in registers.
                    bool     passStructInRegisters = false;
#else // !FEATURE_UNIX_AMD64_STRUCT_PASSING
                    bool     passStructByRef = false;
#endif // !FEATURE_UNIX_AMD64_STRUCT_PASSING

#ifndef _TARGET_X86_
#ifndef FEATURE_UNIX_AMD64_STRUCT_PASSING
                    // Check for struct argument with size 1, 2, 4 or 8 bytes
                    // As we can optimize these by turning them into a GT_IND of the correct type
                    if ((originalSize > TARGET_POINTER_SIZE) || ((originalSize & (originalSize - 1)) != 0))
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING
                    {
                        // Normalize 'size' to the number of pointer sized items
                        // 'size' is the number of register slots that we will use to pass the argument
                        size = roundupSize / TARGET_POINTER_SIZE;
#if defined(_TARGET_AMD64_)
#ifndef FEATURE_UNIX_AMD64_STRUCT_PASSING
                        size = 1;      // This must be copied to a temp and passed by address
                        passStructByRef = true;
                        copyBlkClass = objClass;
#else // FEATURE_UNIX_AMD64_STRUCT_PASSING
                        if (!structDesc.passedInRegisters)
                        {
                            passStructInRegisters = false;
                            copyBlkClass = NO_CLASS_HANDLE;
                        }
                        else
                        {
                            // The objClass is used to materialize the struct on stack.
                            passStructInRegisters = true;
                            copyBlkClass = objClass;
                        }
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING
#elif defined(_TARGET_ARM64_)
                        if (size > 2)
                        {
                            size = 1;      // This must be copied to a temp and passed by address
                            passStructByRef = true;
                            copyBlkClass = objClass;
                        }
#endif

#ifdef _TARGET_ARM_
                        // If we're passing a promoted struct local var, 
                        // we may need to skip some registers due to alignment; record those.
                        GenTreePtr lclVar = fgIsIndirOfAddrOfLocal(argObj);
                        if (lclVar != NULL)
                        {
                            LclVarDsc*  varDsc = &lvaTable[lclVar->gtLclVarCommon.gtLclNum];
                            if (varDsc->lvPromoted)
                            {
                                assert(argObj->OperGet() == GT_OBJ);
                                if (lvaGetPromotionType(varDsc) == PROMOTION_TYPE_INDEPENDENT)
                                {
                                    fgAddSkippedRegsInPromotedStructArg(varDsc, intArgRegNum, &argSkippedRegMask);
                                }
                            }
                        }
#endif // _TARGET_ARM_
                    }
#ifndef FEATURE_UNIX_AMD64_STRUCT_PASSING
                    else 
                    {
                        // change our GT_OBJ into a GT_IND of the correct type.
                        structBaseType = argOrReturnTypeForStruct(originalSize, objClass, false /* forReturn */);
                        // We've already ensured above that size is a power of 2, and less than pointer size.
                        noway_assert(structBaseType != TYP_UNKNOWN);

                        argObj->ChangeOper(GT_IND);

                        // Now see if we can fold *(&X) into X
                        if (argObj->gtOp.gtOp1->gtOper == GT_ADDR)
                        {
                            GenTreePtr temp = argObj->gtOp.gtOp1->gtOp.gtOp1;

                            // Keep the DONT_CSE flag in sync
                            // (as the addr always marks it for its op1)
                            temp->gtFlags &= ~GTF_DONT_CSE;
                            temp->gtFlags |= (argObj->gtFlags & GTF_DONT_CSE);
                            DEBUG_DESTROY_NODE(argObj->gtOp.gtOp1);   // GT_ADDR
                            DEBUG_DESTROY_NODE(argObj);               // GT_IND

                            argObj = temp;
                            *parentOfArgObj = temp;

                            // If the OBJ had been the top level node, we've now changed argx.
                            if (parentOfArgObj == parentArgx)
                                argx = temp;
                        }
                        if (argObj->gtOper == GT_LCL_VAR)
                        {
                            unsigned lclNum = argObj->gtLclVarCommon.gtLclNum;
                            LclVarDsc *  varDsc = &lvaTable[lclNum];

                            if (varDsc->lvPromoted)
                            {
                                if (varDsc->lvFieldCnt == 1) 
                                {
                                    // get the first and only promoted field
                                    LclVarDsc *  fieldVarDsc = &lvaTable[varDsc->lvFieldLclStart];
                                    if (genTypeSize(fieldVarDsc->TypeGet()) >= originalSize)
                                    {
                                        // we will use the first and only promoted field
                                        argObj->gtLclVarCommon.SetLclNum(varDsc->lvFieldLclStart);

                                        if (varTypeCanReg(fieldVarDsc->TypeGet()) && (genTypeSize(fieldVarDsc->TypeGet()) == originalSize))
                                        {
                                            // Just use the existing field's type
                                            argObj->gtType = fieldVarDsc->TypeGet();
                                        }
                                        else 
                                        {
                                            // Can't use the existing field's type, so use GT_LCL_FLD to swizzle
                                            // to a new type
                                            argObj->ChangeOper(GT_LCL_FLD);
                                            argObj->gtType = structBaseType;
                                        }
                                        assert(varTypeCanReg(argObj->TypeGet()));
                                        assert(copyBlkClass == NO_CLASS_HANDLE);
                                    }
                                    else
                                    {
                                        // use GT_LCL_FLD to swizzle the single field struct to a new type
                                        lvaSetVarDoNotEnregister(lclNum DEBUGARG(DNER_LocalField));
                                        argObj->ChangeOper(GT_LCL_FLD);
                                        argObj->gtType = structBaseType;
                                    }
                                }
                                else
                                {
                                    // The struct fits into a single register, but it has been promoted into its
                                    // constituent fields, and so we have to re-assemble it
                                    copyBlkClass = objClass;
#ifdef _TARGET_ARM_
                                    // Alignment constraints may cause us not to use (to "skip") some argument registers.
                                    // Add those, if any, to the skipped (int) arg reg mask.
                                    fgAddSkippedRegsInPromotedStructArg(varDsc, intArgRegNum, &argSkippedRegMask);
#endif // _TARGET_ARM_
                                }
                            }
                            else if (!varTypeIsIntegralOrI(varDsc->TypeGet()))
                            {
                                // Not a promoted struct, so just swizzle the type by using GT_LCL_FLD
                                argObj->ChangeOper(GT_LCL_FLD);
                                argObj->gtType = structBaseType;
                            }
                        }
                        else
                        {
                            // Not a GT_LCL_VAR, so we can just change the type on the node
                            argObj->gtType = structBaseType;
                        }
                        assert(varTypeCanReg(argObj->TypeGet()) ||
                               ((copyBlkClass != NO_CLASS_HANDLE) && varTypeIsIntegral(structBaseType)));

                        size = 1;
                    }
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING

#endif // not _TARGET_X86_
                    // We still have a struct unless we converted the GT_OBJ into a GT_IND above...
                    if ((structBaseType == TYP_STRUCT) &&
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                        !passStructInRegisters
#else // !defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                        !passStructByRef
#endif // !defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                        )
                    {
                        // if the valuetype size is not a multiple of sizeof(void*),
                        // we must copyblk to a temp before doing the obj to avoid
                        // the obj reading memory past the end of the valuetype
#if defined(_TARGET_X86_) && !defined(LEGACY_BACKEND)
                        // TODO-X86-CQ: [1091733] Revisit for small structs, we should use push instruction
                        copyBlkClass = objClass;
                        size = roundupSize / TARGET_POINTER_SIZE;   // Normalize size to number of pointer sized items
#else // !defined(_TARGET_X86_) || defined(LEGACY_BACKEND)
                        if (roundupSize > originalSize)
                        {
                            copyBlkClass = objClass;

                            // There are a few special cases where we can omit using a CopyBlk
                            // where we normally would need to use one.

                            GenTreePtr  objAddr = argObj->gtObj.gtOp1;
                            if (objAddr->gtOper == GT_ADDR)
                            {
                                // exception : no need to use CopyBlk if the valuetype is on the stack
                                if (objAddr->gtFlags & GTF_ADDR_ONSTACK)
                                {
                                    copyBlkClass = NO_CLASS_HANDLE;
                                }
                                // exception : no need to use CopyBlk if the valuetype is already a struct local
                                else if (objAddr->gtOp.gtOp1->gtOper == GT_LCL_VAR)
                                {
                                    copyBlkClass = NO_CLASS_HANDLE;
                                }
                            }
                        }

                        size = roundupSize / TARGET_POINTER_SIZE;   // Normalize size to number of pointer sized items
#endif // !defined(_TARGET_X86_) || defined(LEGACY_BACKEND)
                    }
                }
                if (size > 1)
                {
                    hasMultiregStructArgs = true;
                }
            }

            // The 'size' value has now must have been set. (the original value of zero is an invalid value)
            assert(size != 0);

            //
            // Figure out if the argument will be passed in a register.
            //
            bool passedInRegisters = true;
#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
            passedInRegisters = !isStructArg;
            if (!passedInRegisters)
            {
                if (structDesc.passedInRegisters)
                {
                    passedInRegisters = true;
                }
                else
                {
                    passedInRegisters = false;
                }
            }

#endif
            if (passedInRegisters && isRegParamType(genActualType(argx->TypeGet())))
            {
#ifdef _TARGET_ARM_
                if (passUsingFloatRegs)
                {
                    // First, see if it can be back-filled
                    if (!anyFloatStackArgs &&                   // Is it legal to back-fill? (We haven't put any FP args on the stack yet)
                        (fltArgSkippedRegMask != RBM_NONE) &&   // Is there an available back-fill slot?
                        (size == 1))                            // The size to back-fill is one float register
                    {
                        // Back-fill the register.
                        isBackFilled = true;
                        regMaskTP backFillBitMask = genFindLowestBit(fltArgSkippedRegMask);
                        fltArgSkippedRegMask &= ~backFillBitMask;   // Remove the back-filled register(s) from the skipped mask
                        nextFltArgRegNum = genMapFloatRegNumToRegArgNum(genRegNumFromMask(backFillBitMask));
                        assert(nextFltArgRegNum < MAX_FLOAT_REG_ARG);
                    }

                    // Does the entire float, double, or HFA fit in the FP arg registers?
                    // Check if the last register needed is still in the argument register range.
                    isRegArg = (nextFltArgRegNum + size - 1) < MAX_FLOAT_REG_ARG;

                    if (!isRegArg)
                    {
                        anyFloatStackArgs = true;
                    }
                }
                else
                {
                    isRegArg = intArgRegNum < MAX_REG_ARG;
                }
#elif _TARGET_ARM64_
                if (passUsingFloatRegs)
                {
                    // Check if the last register needed is still in the fp argument register range.
                    isRegArg = (nextFltArgRegNum + (size - 1)) < MAX_FLOAT_REG_ARG;
                }
                else
                {
                    // Check if the last register needed is still in the int argument register range.
                    isRegArg = (intArgRegNum + (size - 1)) < maxRegArgs;
                }
#else // not _TARGET_ARM_ or _TARGET_ARM64_

#if defined(UNIX_AMD64_ABI)

#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                // Here a struct can be passed in register following the classifications of its members and size.
                // Now make sure there are actually enough registers to do so.
                if (isStructArg)
                {
                    for (unsigned int i = 0; i < structDesc.eightByteCount; i++)
                    {
                        if (structDesc.IsIntegralSlot(i))
                        {
                            structIntRegs++;
                        }
                        else if (structDesc.IsSseSlot(i))
                        {
                            structFloatRegs++;
                        }
                    }

                    if (((nextFltArgRegNum + structFloatRegs) > MAX_FLOAT_REG_ARG) ||
                        ((intArgRegNum + structIntRegs) > MAX_REG_ARG))
                    {
                        isRegArg = false;
                        nonRegPassableStruct = true;
                    }
                    else
                    {
                        isRegArg = true;
                        nonRegPassableStruct = false;
                    }
                }
                else
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                {
                    if (passUsingFloatRegs)
                    {
                        isRegArg = nextFltArgRegNum < MAX_FLOAT_REG_ARG;
                    }
                    else
                    {
                        isRegArg = intArgRegNum < MAX_REG_ARG;
                    }
                }
#else // !defined(UNIX_AMD64_ABI)
                isRegArg = (intArgRegNum+(size-1)) < maxRegArgs;
#endif // !defined(UNIX_AMD64_ABI)
#endif // _TARGET_ARM_
            }
            else
            {
                isRegArg = false;

#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
                nonRegPassableStruct = true;
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING
            }
        }

        //
        // Now we know if the argument goes in registers or not and how big it is,
        // whether we had to just compute it or this is a re-morph call and we looked it up.
        //

#ifdef _TARGET_ARM_

        // If we ever allocate a floating point argument to the stack, then all
        // subsequent HFA/float/double arguments go on the stack.
        if (!isRegArg && passUsingFloatRegs)
        {
            for (; fltArgRegNum < MAX_FLOAT_REG_ARG; ++fltArgRegNum)
            {
                fltArgSkippedRegMask |= genMapArgNumToRegMask(fltArgRegNum, TYP_FLOAT);
            }
        }

        // If we think we're going to split a struct between integer registers and the stack, check to
        // see if we've already assigned a floating-point arg to the stack.
        if (isRegArg &&                                 // We decided above to use a register for the argument
            !passUsingFloatRegs &&                      // We're using integer registers
            (intArgRegNum + size > MAX_REG_ARG) &&      // We're going to split a struct type onto registers and stack
            anyFloatStackArgs)                          // We've already used the stack for a floating-point argument
        {
            isRegArg = false;               // Change our mind; don't pass this struct partially in registers

            // Skip the rest of the integer argument registers
            for (; intArgRegNum < MAX_REG_ARG; ++intArgRegNum)
            {
                argSkippedRegMask |= genMapArgNumToRegMask(intArgRegNum, TYP_I_IMPL);
            }
        }

#endif // _TARGET_ARM_
        if (isRegArg)
        {
            regNumber nextRegNum = REG_STK;
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
            regNumber nextOtherRegNum = REG_STK;

            if (isStructArg && structDesc.passedInRegisters)
            {
                // It is a struct passed in registers. Assign the next available register.
                unsigned int curIntReg = intArgRegNum;
                unsigned int curFloatReg = nextFltArgRegNum;
                for (unsigned int i = 0; i < structDesc.eightByteCount; i++)
                {
                    if (structDesc.IsIntegralSlot(i))
                    {
                        if (i == 0)
                        {
                            nextRegNum = genMapIntRegArgNumToRegNum(curIntReg);

                            // For non-completed args the counters are incremented already
                            // in the !lateArgsComputed above.
                            if (lateArgsComputed)
                            {
                                structIntRegs++;
                            }
                        }
                        else if (i == 1)
                        {
                            nextOtherRegNum = genMapIntRegArgNumToRegNum(curIntReg);

                            if (lateArgsComputed)
                            {
                                structIntRegs++;
                            }
                        }
                        else
                        {
                            assert(false && "fgMorphArgs Invalid index for int classification.");
                        }

                        curIntReg++;
                    }
                    else if (structDesc.IsSseSlot(i))
                    {
                        if (i == 0)
                        {
                            nextRegNum = genMapFloatRegArgNumToRegNum(curFloatReg);

                            if (lateArgsComputed)
                            {
                                structFloatRegs++;
                            }
                        }
                        else if (i == 1)
                        {
                            nextOtherRegNum = genMapFloatRegArgNumToRegNum(curFloatReg);

                            if (lateArgsComputed)
                            {
                                structFloatRegs++;
                            }
                        }
                        else
                        {
                            assert(false && "fgMorphArgs Invalid index for SSE classification.");
                        }

                        curFloatReg++;
                    }
                }
            }
            else
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
            {
                // fill in or update the argInfo table 
                nextRegNum = passUsingFloatRegs ? genMapFloatRegArgNumToRegNum(nextFltArgRegNum) : genMapIntRegArgNumToRegNum(intArgRegNum);
            }

#ifdef _TARGET_AMD64_
#ifndef FEATURE_UNIX_AMD64_STRUCT_PASSING
            assert(size == 1);
#endif
#endif

#ifndef LEGACY_BACKEND
            // If there are nonstandard args (outside the calling convention) they were inserted above
            // and noted them in a table so we can recognize them here and build their argInfo.
            // 
            // They should not affect the placement of any other args or stack space required.
            // Example: on AMD64 R10 and R11 are used for indirect VSD (generic interface) and cookie calls.
            bool nonStandardFound = false;
            for (int i=0; i<nonStandardArgs.Height(); i++)
            {
                hasNonStandardArg = true;
                if (argx == nonStandardArgs.Index(i).node)
                {
                    fgArgTabEntry* argEntry = call->fgArgInfo->AddRegArg(argIndex, 
                                                                         argx,
                                                                         args, 
                                                                         nonStandardArgs.Index(i).reg, 
                                                                         size, 
                                                                         argAlign
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                                                                         , isStructArg, 
                                                                         nextOtherRegNum, 
                                                                         &structDesc
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                    );
                    argEntry->isNonStandard = true;
                    argIndex++;
                    nonStandardFound = true;
                    break;
                }
            }
            if (nonStandardFound)
                continue;
#endif // !LEGACY_BACKEND

            if (!lateArgsComputed)
            {
                // This is a register argument - put it in the table
                fgArgTabEntryPtr newArg = call->fgArgInfo->AddRegArg(argIndex, 
                                                                     argx, 
                                                                     args, 
                                                                     nextRegNum, 
                                                                     size, 
                                                                     argAlign
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                                                                     , isStructArg, 
                                                                     nextOtherRegNum, 
                                                                     &structDesc
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                    );
                (void)newArg; //prevent "unused variable" error from GCC
#ifdef _TARGET_ARM_
                newArg->SetIsHfaRegArg(passUsingFloatRegs && isHfaArg); // Note that an HFA is passed in int regs for varargs
                newArg->SetIsBackFilled(isBackFilled);
#endif // _TARGET_ARM_
            }
            else
            {
                // This is a register argument - possibly update it in the table
                fgArgTabEntryPtr entry = call->fgArgInfo->RemorphRegArg(argIndex, argx, args, nextRegNum, size, argAlign);
                if (entry->isNonStandard)
                {
                    argIndex++;
                    continue;
                }
            }

            // Setup the next argRegNum value
            if (!isBackFilled)
            {
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                if (isStructArg)
                {
                    intArgRegNum += structIntRegs;
                    fltArgRegNum += structFloatRegs;
                }
                else
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
                {
                    if (passUsingFloatRegs)
                    {
                        fltArgRegNum += size;

#if defined(_TARGET_AMD64_) && !defined(UNIX_AMD64_ABI)
                        argSkippedRegMask |= genMapArgNumToRegMask(intArgRegNum, TYP_I_IMPL);
                        intArgRegNum = min(intArgRegNum + size, MAX_REG_ARG);
#endif // _TARGET_AMD64_
#ifdef _TARGET_ARM_
                        if (fltArgRegNum > MAX_FLOAT_REG_ARG)
                        {
                            // This indicates a partial enregistration of a struct type
                            assert(varTypeIsStruct(argx));
                            unsigned numRegsPartial = size - (fltArgRegNum - MAX_FLOAT_REG_ARG);
                            assert((unsigned char)numRegsPartial == numRegsPartial);
                            call->fgArgInfo->SplitArg(argIndex, numRegsPartial, size - numRegsPartial);
                            fltArgRegNum = MAX_FLOAT_REG_ARG;
                        }
#endif // _TARGET_ARM_
                    }
                    else
                    {
                        intArgRegNum += size;

#if defined(_TARGET_AMD64_) && !defined(UNIX_AMD64_ABI)
                        fltArgSkippedRegMask |= genMapArgNumToRegMask(fltArgRegNum, TYP_DOUBLE);
                        fltArgRegNum = min(fltArgRegNum + size, MAX_FLOAT_REG_ARG);
#endif // _TARGET_AMD64_
#ifdef _TARGET_ARM_
                        if (intArgRegNum > MAX_REG_ARG)
                        {
                            // This indicates a partial enregistration of a struct type
                            assert((isStructArg) || argx->OperIsCopyBlkOp() ||
                                (argx->gtOper == GT_COMMA && (args->gtFlags & GTF_ASG)));
                            unsigned numRegsPartial = size - (intArgRegNum - MAX_REG_ARG);
                            assert((unsigned char)numRegsPartial == numRegsPartial);
                            call->fgArgInfo->SplitArg(argIndex, numRegsPartial, size - numRegsPartial);
                            intArgRegNum = MAX_REG_ARG;
                            fgPtrArgCntCur += size - numRegsPartial;
                        }
#endif // _TARGET_ARM_
                    }
                }
            }
        }
        else  // We have an argument that is not passed in a register
        {
            fgPtrArgCntCur += size;

            // If the register arguments have not been determined then we must fill in the argInfo

            if  (!lateArgsComputed)
            {
                // This is a stack argument - put it in the table
                call->fgArgInfo->AddStkArg(argIndex, argx, args, size, argAlign FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY_ARG(isStructArg));

            }
            else
            {
                // This is a stack argument - possibly update it in the table
                call->fgArgInfo->RemorphStkArg(argIndex, argx, args, size, argAlign);
            }
        }
        if (copyBlkClass != NO_CLASS_HANDLE)
        {
            noway_assert(!lateArgsComputed);
            fgMakeOutgoingStructArgCopy(call, args, argIndex, copyBlkClass FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY_ARG(&structDesc));
        }

#ifndef LEGACY_BACKEND
        if (argx->gtOper == GT_MKREFANY)
        {
            NYI_X86("MKREFANY");

            // 'Lower' the MKREFANY tree and insert it.
            noway_assert(!lateArgsComputed);

            // Get a new temp
            // Here we don't need unsafe value cls check since the addr of temp is used only in mkrefany
            unsigned   tmp = lvaGrabTemp(true DEBUGARG("by-value mkrefany struct argument"));
            lvaSetStruct(tmp, impGetRefAnyClass(), false);


            // Build the mkrefany as a comma node:
            // (tmp.ptr=argx),(tmp.type=handle)
            GenTreeLclFld* destPtrSlot  = gtNewLclFldNode(tmp, TYP_I_IMPL, offsetof(CORINFO_RefAny, dataPtr));
            GenTreeLclFld* destTypeSlot = gtNewLclFldNode(tmp, TYP_I_IMPL, offsetof(CORINFO_RefAny, type));
            destPtrSlot->gtFieldSeq  = GetFieldSeqStore()->CreateSingleton(GetRefanyDataField());
            destPtrSlot->gtFlags |= GTF_VAR_DEF;
            destTypeSlot->gtFieldSeq = GetFieldSeqStore()->CreateSingleton(GetRefanyTypeField());
            destTypeSlot->gtFlags |= GTF_VAR_DEF;

            GenTreePtr asgPtrSlot   = gtNewAssignNode(destPtrSlot, argx->gtOp.gtOp1);
            GenTreePtr asgTypeSlot  = gtNewAssignNode(destTypeSlot, argx->gtOp.gtOp2);
            GenTreePtr asg = gtNewOperNode(GT_COMMA, TYP_VOID, asgPtrSlot, asgTypeSlot);

            // Change the expression to "(tmp=val)"
            args->gtOp.gtOp1 = asg;

            // EvalArgsToTemps will cause tmp to actually get loaded as the argument
            call->fgArgInfo->EvalToTmp(argIndex, tmp, asg);
            lvaSetVarAddrExposed(tmp);
        }
#endif // !LEGACY_BACKEND

        argIndex++;
#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
        if (nonRegPassableStruct)
        {
            nonRegPassedStructSlots += size;
        }
        else
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING
        {
            argSlots += size;
        }
    } // end foreach argument loop

    if  (!lateArgsComputed)
    {
        call->fgArgInfo->ArgsComplete();

        call->gtCallRegUsedMask = genIntAllRegArgMask(intArgRegNum) & ~argSkippedRegMask;
        if (fltArgRegNum > 0)
        {
#if defined(_TARGET_ARM_) || defined(_TARGET_AMD64_)
            call->gtCallRegUsedMask |= genFltAllRegArgMask(fltArgRegNum) & ~fltArgSkippedRegMask;
#endif
        }
    }

    if (call->gtCallArgs)
    {
        UpdateGT_LISTFlags(call->gtCallArgs);
    }

    /* Process the function address, if indirect call */

    if (call->gtCallType == CT_INDIRECT)
        call->gtCallAddr = fgMorphTree(call->gtCallAddr);

    call->fgArgInfo->RecordStkLevel(fgPtrArgCntCur);

    if ((call->gtCallType == CT_INDIRECT) && (call->gtCallCookie != NULL))
        fgPtrArgCntCur++;

    /* Remember the maximum value we ever see */

    if  (fgPtrArgCntMax < fgPtrArgCntCur)
         fgPtrArgCntMax = fgPtrArgCntCur;

    /* The call will pop all the arguments we pushed */

    fgPtrArgCntCur = genPtrArgCntSav;

#if FEATURE_FIXED_OUT_ARGS

    // Update the outgoing argument size.
    // If the call is a fast tail call, it will setup its arguments in incoming arg
    // area instead of the out-going arg area.  Therefore, don't consider fast tail
    // calls to update lvaOutgoingArgSpaceSize.
    if (!call->IsFastTailCall())
    {
        unsigned        preallocatedArgCount;

#if defined(_TARGET_ARMARCH_)
        // First slots go in registers only, no stack needed.
        // TODO-ARMArch-CQ: This calculation is only accurate for integer arguments,
        // and ignores floating point args (it is overly conservative in that case).
        if (argSlots <= MAX_REG_ARG)
        {
            preallocatedArgCount = 0;
        }
        else
        {
            preallocatedArgCount = argSlots - MAX_REG_ARG;
        }
#elif defined(UNIX_AMD64_ABI)
        opts.compNeedToAlignFrame = true;
        // First slots go in registers only, no stack needed.
        // TODO-Amd64-Unix-CQ This calculation is only accurate for integer arguments,
        // and ignores floating point args (it is overly conservative in that case).
        if (argSlots <= MAX_REG_ARG)
        {
            preallocatedArgCount = nonRegPassedStructSlots;
        }
        else
        {
            preallocatedArgCount = argSlots + nonRegPassedStructSlots - MAX_REG_ARG;
        }
#elif defined(_TARGET_AMD64_)
        preallocatedArgCount = max(4, argSlots);
#else
#error Unsupported or unset target architecture
#endif // _TARGET_*
        if (preallocatedArgCount * REGSIZE_BYTES > lvaOutgoingArgSpaceSize)
        {
            lvaOutgoingArgSpaceSize = preallocatedArgCount * REGSIZE_BYTES;

            // If a function has localloc, we will need to move the outgoing arg space when the
            // localloc happens. When we do this, we need to maintain stack alignment. To avoid
            // leaving alignment-related holes when doing this move, make sure the outgoing
            // argument space size is a multiple of the stack alignment by aligning up to the next
            // stack alignment boundary.
            if (compLocallocUsed)
            {
                lvaOutgoingArgSpaceSize = (lvaOutgoingArgSpaceSize + (STACK_ALIGN - 1)) & ~(STACK_ALIGN - 1);
            }
        }
    }
#endif // FEATURE_FIXED_OUT_ARGS

    /* Update the 'side effect' flags value for the call */

    call->gtFlags |= (flagsSummary & GTF_ALL_EFFECT);

    // If the register arguments have already been determined
    // or we have no register arguments then we are done.

    bool needEvalArgsToTemps = true;

    if (lateArgsComputed || (intArgRegNum == 0 && fltArgRegNum == 0 && !hasNonStandardArg && !hasStructArgument))
    {
        needEvalArgsToTemps = false;
    }

    if (needEvalArgsToTemps)
    {
        // This is the first time that we morph this call AND it has register arguments.
        // Follow into the code below and do the 'defer or eval to temp' analysis.

        call->fgArgInfo->SortArgs();

        call->fgArgInfo->EvalArgsToTemps();

        // We may have updated the arguments
        if (call->gtCallArgs)
        {
            UpdateGT_LISTFlags(call->gtCallArgs);
        }
    }

#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING

    // Rewrite the struct args to be passed by value on stack or in registers.
    fgMorphSystemVStructArgs(call, hasStructArgument);

#else // !FEATURE_UNIX_AMD64_STRUCT_PASSING

    // In the future we can migrate UNIX_AMD64 to use this
    // method instead of fgMorphSystemVStructArgs
#ifndef LEGACY_BACKEND
    // We only build GT_LISTs for MultiReg structs for the RyuJIT backend
    if (hasMultiregStructArgs)
    {
        fgMorphMultiregStructArgs(call);
    }
#endif // LEGACY_BACKEND

#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING

    return call;
}
#ifdef _PREFAST_
#pragma warning(pop)
#endif

#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
// fgMorphSystemVStructArgs:
//   Rewrite the struct args to be passed by value on stack or in registers.
//
// args:
//   call: The call whose arguments need to be morphed.
//   hasStructArgument: Whether this call has struct arguments.
//   
void Compiler::fgMorphSystemVStructArgs(GenTreeCall* call, bool hasStructArgument)
{
    unsigned flagsSummary = 0;
    GenTreePtr      args;
    GenTreePtr      argx;

    if (hasStructArgument)
    {
        fgArgInfoPtr allArgInfo = call->fgArgInfo;

        for (args = call->gtCallArgs; args != nullptr; args = args->gtOp.gtOp2)
        {
            // For late arguments the arg tree that is overridden is in the gtCallLateArgs list. 
            // For such late args the gtCallArgList contains the setup arg node (evaluating the arg.) 
            // The tree from the gtCallLateArgs list is passed to the callee. The fgArgEntry node contains the mapping
            // between the nodes in both lists. If the arg is not a late arg, the fgArgEntry->node points to itself,
            // otherwise points to the list in the late args list.
            bool isLateArg = (args->gtOp.gtOp1->gtFlags & GTF_LATE_ARG) != 0;
            fgArgTabEntryPtr fgEntryPtr = gtArgEntryByNode(call, args->gtOp.gtOp1);
            assert(fgEntryPtr != nullptr);
            GenTreePtr argx = fgEntryPtr->node;
            GenTreePtr lateList = nullptr;
            GenTreePtr lateNode = nullptr;

            if (isLateArg)
            {
                for (GenTreePtr list = call->gtCallLateArgs; list; list = list->MoveNext())
                {
                    assert(list->IsList());

                    GenTreePtr argNode = list->Current();
                    if (argx == argNode)
                    {
                        lateList = list;
                        lateNode = argNode;
                        break;
                    }
                }
                assert(lateList != nullptr && lateNode != nullptr);
            }
            GenTreePtr arg = argx;
            bool argListCreated = false;

            var_types  type = arg->TypeGet();

            if (varTypeIsStruct(type))
            {
                var_types originalType = type;
                // If we have already processed the arg...
                if (arg->OperGet() == GT_LIST && varTypeIsStruct(arg))
                {
                    continue;
                }

                // If already OBJ it is set properly already.
                if (arg->OperGet() == GT_OBJ)
                {
                    assert(!fgEntryPtr->structDesc.passedInRegisters);
                    continue;
                }

                assert(
                    arg->OperGet() == GT_LCL_VAR ||
                    arg->OperGet() == GT_LCL_FLD ||
                    (arg->OperGet() == GT_ADDR &&
                        (arg->gtOp.gtOp1->OperGet() == GT_LCL_FLD ||
                         arg->gtOp.gtOp1->OperGet() == GT_LCL_VAR)));

                GenTreeLclVarCommon* lclCommon = arg->OperGet() == GT_ADDR ?
                    arg->gtOp.gtOp1->AsLclVarCommon() : arg->AsLclVarCommon();
                if (fgEntryPtr->structDesc.passedInRegisters)
                {
                    if (fgEntryPtr->structDesc.eightByteCount == 1)
                    {
                        // Change the type and below the code will change the LclVar to a LCL_FLD
                        type = GetTypeFromClassificationAndSizes(fgEntryPtr->structDesc.eightByteClassifications[0], fgEntryPtr->structDesc.eightByteSizes[0]);
                    }
                    else if (fgEntryPtr->structDesc.eightByteCount == 2)
                    {
                        // Create LCL_FLD for each eightbyte.
                        argListCreated = true;

                        // Second eightbyte.
                        GenTreeLclFld* newLclField = new(this, GT_LCL_FLD) GenTreeLclFld(
                            GetTypeFromClassificationAndSizes(
                                fgEntryPtr->structDesc.eightByteClassifications[1],
                                fgEntryPtr->structDesc.eightByteSizes[1]),
                            lclCommon->gtLclNum,
                            fgEntryPtr->structDesc.eightByteOffsets[1]);
                        // Note this should actually be: secondNode = gtNewArgList(newLclField)
                        GenTreeArgList* secondNode = gtNewListNode(newLclField, nullptr);
                        secondNode->gtType = originalType; // Preserve the type. It is a special case.
                        newLclField->gtFieldSeq = FieldSeqStore::NotAField();

                        // First field
                        arg->AsLclFld()->gtFieldSeq = FieldSeqStore::NotAField();
                        arg->gtType = GetTypeFromClassificationAndSizes(
                            fgEntryPtr->structDesc.eightByteClassifications[0],
                            fgEntryPtr->structDesc.eightByteSizes[0]);
                        arg = gtNewListNode(arg, secondNode);
                        arg->gtType = type; // Preserve the type. It is a special case.
                    }
                    else
                    {
                        assert(false && "More than two eightbytes detected for CLR."); // No more than two eightbytes for the CLR.
                    }
                }

                // If we didn't change the type of the struct, it means
                // its classification doesn't support to be passed directly through a
                // register, so we need to pass a pointer to the destination where
                // where we copied the struct to.
                if (!argListCreated)
                {
                    if (fgEntryPtr->structDesc.passedInRegisters)
                    {
                        arg->gtType = type;
                    }
                    else
                    {
                        // Make sure this is an addr node.
                        if (arg->OperGet() != GT_ADDR && arg->OperGet() != GT_LCL_VAR_ADDR)
                        {
                            arg = gtNewOperNode(GT_ADDR, TYP_I_IMPL, arg);
                        }

                        assert(arg->OperGet() == GT_ADDR || arg->OperGet() == GT_LCL_VAR_ADDR);

                        // Create an Obj of the temp to use it as a call argument.
                        arg = new (this, GT_OBJ) GenTreeObj(originalType, arg, lvaGetStruct(lclCommon->gtLclNum));
                        arg->gtFlags |= GTF_EXCEPT;
                        flagsSummary |= GTF_EXCEPT;
                    }
                }
            }

            if (argx != arg)
            {
                bool isLateArg = (args->gtOp.gtOp1->gtFlags & GTF_LATE_ARG) != 0;
                fgArgTabEntryPtr fgEntryPtr = gtArgEntryByNode(call, args->gtOp.gtOp1);
                assert(fgEntryPtr != nullptr);
                GenTreePtr argx = fgEntryPtr->node;
                GenTreePtr lateList = nullptr;
                GenTreePtr lateNode = nullptr;
                if (isLateArg)
                {
                    for (GenTreePtr list = call->gtCallLateArgs; list; list = list->MoveNext())
                    {
                        assert(list->IsList());

                        GenTreePtr argNode = list->Current();
                        if (argx == argNode)
                        {
                            lateList = list;
                            lateNode = argNode;
                            break;
                        }
                    }
                    assert(lateList != nullptr && lateNode != nullptr);
                }

                fgEntryPtr->node = arg;
                if (isLateArg)
                {
                    lateList->gtOp.gtOp1 = arg;
                }
                else
                {
                    args->gtOp.gtOp1 = arg;
                }
            }
        }
    }

    // Update the flags
    call->gtFlags |= (flagsSummary & GTF_ALL_EFFECT);
}
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING

//-----------------------------------------------------------------------------
// fgMorphMultiregStructArgs:  Locate the TYP_STRUCT arguments and 
//                             call fgMorphMultiregStructArg on each of them.
//
// Arguments:
//    call:    a GenTreeCall node that has one or more TYP_STRUCT arguments
//
// Notes:
//    We only call fgMorphMultiregStructArg for the register passed TYP_STRUCT arguments.
//    The call to fgMorphMultiregStructArg will mutate the argument into the GT_LIST form
//    whicj is only used for register arguments.
//    If this method fails to find any TYP_STRUCT arguments it will assert.
//
void Compiler::fgMorphMultiregStructArgs(GenTreeCall* call)
{
    GenTreePtr   args;
    GenTreePtr   argx;
    bool         foundStructArg = false;
    unsigned     initialFlags = call->gtFlags;
    unsigned     flagsSummary = 0;
    fgArgInfoPtr allArgInfo = call->fgArgInfo;

    // Currently only ARM64 is using this method to morph the MultiReg struct args
    //  in the future AMD64_UNIX and for HFAs ARM32, will also use this method
    //
#ifdef _TARGET_ARM_
    NYI_ARM("fgMorphMultiregStructArgs");
#endif
#ifdef _TARGET_X86_
    assert("Logic error: no MultiregStructArgs for X86");
#endif
#ifdef _TARGET_AMD64_
#if defined(UNIX_AMD64_ABI)
    NYI_AMD64("fgMorphMultiregStructArgs (UNIX ABI)");
#else
#endif
    assert("Logic error: no MultiregStructArgs for Windows X64 ABI");
#endif

    for (args = call->gtCallArgs; args != nullptr; args = args->gtOp.gtOp2)
    {
        // For late arguments the arg tree that is overridden is in the gtCallLateArgs list. 
        // For such late args the gtCallArgList contains the setup arg node (evaluating the arg.) 
        // The tree from the gtCallLateArgs list is passed to the callee. The fgArgEntry node contains the mapping
        // between the nodes in both lists. If the arg is not a late arg, the fgArgEntry->node points to itself,
        // otherwise points to the list in the late args list.
        bool isLateArg = (args->gtOp.gtOp1->gtFlags & GTF_LATE_ARG) != 0;
        fgArgTabEntryPtr fgEntryPtr = gtArgEntryByNode(call, args->gtOp.gtOp1);
        assert(fgEntryPtr != nullptr);
        GenTreePtr argx = fgEntryPtr->node;
        GenTreePtr lateList = nullptr;
        GenTreePtr lateNode = nullptr;

        if (isLateArg)
        {
            for (GenTreePtr list = call->gtCallLateArgs; list; list = list->MoveNext())
            {
                assert(list->IsList());

                GenTreePtr argNode = list->Current();
                if (argx == argNode)
                {
                    lateList = list;
                    lateNode = argNode;
                    break;
                }
            }
            assert(lateList != nullptr && lateNode != nullptr);
        }

        GenTreePtr arg = argx;

        if (arg->TypeGet() == TYP_STRUCT)
        {
            foundStructArg = true;

            arg = fgMorphMultiregStructArg(arg, fgEntryPtr);

            // Did we replace 'argx' with a new tree?
            if (arg != argx)
            {
                fgEntryPtr->node = arg;   // Record the new value for the arg in the fgEntryPtr->node

                // link the new arg node into either the late arg list or the gtCallArgs list
                if (isLateArg)
                {
                    lateList->gtOp.gtOp1 = arg;
                }
                else
                {
                    args->gtOp.gtOp1 = arg;
                }
            }
        }
    }

    // We should only call this method when we actually have one or more multireg struct args
    assert(foundStructArg);

    // Update the flags
    call->gtFlags |= (flagsSummary & GTF_ALL_EFFECT);
}


//-----------------------------------------------------------------------------
// fgMorphMultiregStructArg:  Given a multireg TYP_STRUCT arg from a call argument list
//   Morph the argument into a set of GT_LIST nodes.
//
// Arguments:
//     arg   - A GenTree node containing a TYP_STRUCT arg that 
//             is to be passed in multiple registers
// Notes:
//    arg must be a GT_OBJ or GT_LCL_VAR or GT_LCL_FLD of TYP_STRUCT that is suitable
//    for passing in multiple registers.
//    If arg is a LclVar we check if it is struct promoted and has the right number of fields
//    and if they are at the appropriate offsets we will use the struct promted fields
//    in the GT_LIST nodes that we create.
//    If we have a GT_LCL_VAR that isn't struct promoted or doesn't meet the requirements
//    we will use a set of GT_LCL_FLDs nodes to access the various portions of the struct
//    this also forces the struct to be stack allocated into the local frame.
//    For the GT_OBJ case will clone the address expression and generate two (or more)
//    indirections.
//    Currently the implementation only handles ARM64 and will NYI for other architectures.
//    And for ARM64 we do not ye handle HFA arguments, so only 16-byte struct sizes are supported.
//
GenTreePtr    Compiler::fgMorphMultiregStructArg(GenTreePtr arg, fgArgTabEntryPtr fgEntryPtr)
{
    GenTreeArgList*  newArg = nullptr;
    assert(arg->TypeGet() == TYP_STRUCT);
    GenTreePtr argValue = arg;

#ifndef _TARGET_ARM64_
    NYI("fgMorphMultiregStructArg non-ARM64 implementation");
#endif

    // If we have a GT_OBJ of a GT_ADDR then
    //  we set argValue to the child node ofthe GT_ADDR
    if (arg->OperGet() == GT_OBJ)
    {
        GenTreePtr argAddr = arg->gtOp.gtOp1;

        if (argAddr->OperGet() == GT_ADDR)
        {
            argValue = argAddr->gtOp.gtOp1;
        }
    }
    // We should still have a TYP_STRUCT
    assert(argValue->TypeGet() == TYP_STRUCT);

    // Are we passing a struct LclVar?
    //
    if (argValue->OperGet() == GT_LCL_VAR)
    {
        GenTreeLclVarCommon* varNode = argValue->AsLclVarCommon();
        unsigned   varNum = varNode->gtLclNum;
        assert(varNum < lvaCount);
        LclVarDsc* varDsc = &lvaTable[varNum];

        // At this point any TYP_STRUCT LclVar must be a 16-byte pass by value argument
        assert(varDsc->lvSize() == 2 * TARGET_POINTER_SIZE);

        const BYTE * gcPtrs = varDsc->lvGcLayout;

        var_types type0 = getJitGCType(gcPtrs[0]);
        var_types type1 = getJitGCType(gcPtrs[1]);

        varDsc->lvIsMultiRegArgOrRet = true;

        // Is this LclVar a promoted struct with exactly two fields?
        if ((varDsc->lvPromoted) && (varDsc->lvFieldCnt == 2))
        {
            // See if we have two promoted fields that start at offset 0 and 8?
            unsigned loVarNum = lvaGetFieldLocal(varDsc, 0);
            unsigned hiVarNum = lvaGetFieldLocal(varDsc, TARGET_POINTER_SIZE);

            // Did we find the promoted fields at the necessary offsets?
            if ((loVarNum != BAD_VAR_NUM) && (hiVarNum != BAD_VAR_NUM))
            {
                LclVarDsc* loVarDsc = &lvaTable[loVarNum];
                LclVarDsc* hiVarDsc = &lvaTable[hiVarNum];

                var_types  loType = loVarDsc->lvType;
                var_types  hiType = hiVarDsc->lvType;

                if (varTypeIsFloating(loType) || varTypeIsFloating(hiType))
                {
                    // TODO-LSRA - It currently doesn't support the passing of floating point LCL_VARS in the integer registers
                    // So for now we will use GT_LCLFLD's to pass this struct (it won't be enregistered)
                    //
                    JITDUMP("Multireg struct V%02u will be passed using GT_LCLFLD because it has float fields.\n", varNum);
                    //
                    // we call lvaSetVarDoNotEnregister and do the proper transformation below.
                    //
                }
                else
                {
                    // We can use the struct promoted field as the two arguments

                    GenTreePtr loLclVar = gtNewLclvNode(loVarNum, loType, loVarNum);
                    GenTreePtr hiLclVar = gtNewLclvNode(hiVarNum, hiType, hiVarNum);

                    // Create a new tree for 'arg'
                    //    replace the existing LDOBJ(ADDR(LCLVAR)) 
                    //    with a LIST(LCLVAR-LO, LIST(LCLVAR-HI, nullptr))
                    //
                    newArg = gtNewListNode(loLclVar, gtNewArgList(hiLclVar));
                }
            }
        }

        // Check if we couldn't transform the LDOBJ(ADDR(LCLVAR)) into a struct promoted GT_LIST above
        if (newArg == nullptr)
        {
            //
            // We weren't able to pass this LclVar using it's struct promted fields
            //
            // So instead we will create a list of GT_LCL_FLDs nodes to pass this struct
            //
            lvaSetVarDoNotEnregister(varNum DEBUG_ARG(DNER_LocalField));

            // If this is going in the register area, we transform it here into a GT_LIST of LCLFLD's
            // If this is going in the outgoing arg area, it will be transformed later
            //
            if (fgEntryPtr->regNum != REG_STK)
            {
                GenTreeLclVarCommon* varNode = argValue->AsLclVarCommon();
                unsigned   varNum = varNode->gtLclNum;
                assert(varNum < lvaCount);
                LclVarDsc* varDsc = &lvaTable[varNum];

                GenTreePtr loLclFld = gtNewLclFldNode(varNum, type0, 0);
                GenTreePtr hiLclFld = gtNewLclFldNode(varNum, type1, TARGET_POINTER_SIZE);

                // Create a new tree for 'arg'
                //    replace the existing LDOBJ(ADDR(LCLVAR)) 
                //    with a LIST(LCLFLD-LO, LIST(LCLFLD-HI, nullptr))
                //
                newArg = gtNewListNode(loLclFld, gtNewArgList(hiLclFld));
            }
        }
    }
    // Check if we already created a replacement newArg above
    if (newArg == nullptr)
    {
        if (fgEntryPtr->regNum == REG_STK)
        {
            // We leave this stack passed argument alone
            return arg;
        }
    }

    // Are we passing a GT_LCL_FLD which contain a 16-byte struct inside it?
    //
    if (argValue->OperGet() == GT_LCL_FLD)
    {
        GenTreeLclVarCommon* varNode = argValue->AsLclVarCommon();
        unsigned   varNum = varNode->gtLclNum;
        assert(varNum < lvaCount);
        LclVarDsc* varDsc = &lvaTable[varNum];

        unsigned baseOffset   = argValue->gtLclFld.gtLclOffs;
        unsigned baseIndex    = baseOffset / TARGET_POINTER_SIZE;
        unsigned requiredSize = baseOffset + (2 * TARGET_POINTER_SIZE);

        // The allocated size of our LocalVar must be at least as big as requiredSize
        assert(varDsc->lvSize() >= requiredSize);

        const BYTE * gcPtrs = varDsc->lvGcLayout;

        var_types type0 = getJitGCType(gcPtrs[baseIndex+0]);
        var_types type1 = getJitGCType(gcPtrs[baseIndex+1]);

        //
        // We create a list of two GT_LCL_FLDs nodes to pass this struct
        //
        lvaSetVarDoNotEnregister(varNum DEBUG_ARG(DNER_LocalField));

        GenTreePtr loLclFld = gtNewLclFldNode(varNum, type0, baseOffset);
        GenTreePtr hiLclFld = gtNewLclFldNode(varNum, type1, baseOffset + TARGET_POINTER_SIZE);

        // Create a new tree for 'arg'
        //    replace the existing LDOBJ(ADDR(LCLVAR)) 
        //    with a LIST(LCLFLD-LO, LIST(LCLFLD-HI, nullptr))
        //
        newArg = gtNewListNode(loLclFld, gtNewArgList(hiLclFld));
    }
    // Are we passing a GT_OBJ struct?
    //
    else if (argValue->OperGet() == GT_OBJ)
    {
        GenTreeObj*          argObj   = argValue->AsObj();
        CORINFO_CLASS_HANDLE objClass = argObj->gtClass;

        int structSize = info.compCompHnd->getClassSize(objClass);
        assert(structSize <= 2 * TARGET_POINTER_SIZE);
        BYTE gcPtrs[2] = { TYPE_GC_NONE, TYPE_GC_NONE };
        info.compCompHnd->getClassGClayout(objClass, &gcPtrs[0]);

        var_types  type0 = getJitGCType(gcPtrs[0]);
        var_types  type1 = getJitGCType(gcPtrs[1]);

        GenTreePtr  baseAddr    = argObj->gtOp1;
        GenTreePtr  baseAddrDup = gtCloneExpr(baseAddr);
        noway_assert(baseAddrDup != nullptr);

        var_types   addrType = baseAddr->TypeGet();
        GenTreePtr  loAddr   = baseAddr;
        GenTreePtr  hiAddr   = gtNewOperNode(GT_ADD, addrType, baseAddrDup, gtNewIconNode(TARGET_POINTER_SIZE, TYP_I_IMPL));
        GenTreePtr  loValue  = gtNewOperNode(GT_IND, type0, loAddr);
        GenTreePtr  hiValue  = gtNewOperNode(GT_IND, type1, hiAddr);

        // Create a new tree for 'arg'
        //    replace the existing LDOBJ(EXPR) 
        //    with a LIST(IND(EXPR), LIST(IND(EXPR+8), nullptr))
        //
        newArg = gtNewListNode(loValue, gtNewArgList(hiValue));
    }

    // If we reach here we should have set newArg to something 
    if (newArg == nullptr)
    {
#ifdef DEBUG
        gtDispTree(argValue);
#endif
        assert(!"Missing case in fgMorphMultiregStructArg");
    }

#ifdef DEBUG
    if (verbose)
    {
        printf("fgMorphMultiregStructArg created tree:\n");
        gtDispTree(newArg);
    }
#endif

    arg = newArg;   // consider calling fgMorphTree(newArg);
    return arg;
}

// Make a copy of a struct variable if necessary, to pass to a callee.
// returns: tree that computes address of the outgoing arg
void
Compiler::fgMakeOutgoingStructArgCopy(GenTreeCall* call, 
                                      GenTree* args, 
                                      unsigned argIndex, 
                                      CORINFO_CLASS_HANDLE copyBlkClass
                                      FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY_ARG(const SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR* const structDescPtr))
{
    GenTree* argx = args->Current();
    noway_assert(argx->gtOper != GT_MKREFANY);
    // See if we need to insert a copy at all
    // Case 1: don't need a copy if it is the last use of a local.  We can't determine that all of the time
    // but if there is only one use and no loops, the use must be last.
    if (argx->gtOper == GT_OBJ)
    {
        GenTree* lcl = argx->gtOp.gtOp1;
        if (lcl->OperIsLocal())
        {
            unsigned varNum = lcl->AsLclVarCommon()->GetLclNum();
            if (lvaIsImplicitByRefLocal(varNum))
            {
                LclVarDsc* varDsc = &lvaTable[varNum];
                if (varDsc->lvRefCnt == 1 && !fgMightHaveLoop())
                {
                    varDsc->lvRefCnt = 0;
                    args->gtOp.gtOp1 = lcl;
                    fgArgTabEntryPtr fp = Compiler::gtArgEntryByNode(call, argx);
                    fp->node = lcl;

                    JITDUMP("did not have to make outgoing copy for V%2d", varNum);
                    varDsc->lvRefCnt = 0;
                    return;
                }
                else
                {
                    varDsc->lvRefCnt = 0;
                }
            }
        }
    }

    if (fgOutgoingArgTemps == nullptr)
        fgOutgoingArgTemps = hashBv::Create(this);

    unsigned   tmp = 0;
    bool found = false;
            
    // Attempt to find a local we have already used for an outgoing struct and reuse it.
    // We do not reuse within a statement.
    if (!opts.MinOpts())
    {
        indexType lclNum;
        FOREACH_HBV_BIT_SET(lclNum, fgOutgoingArgTemps)
        {
            LclVarDsc* varDsc = &lvaTable[lclNum];
            if (typeInfo::AreEquivalent(varDsc->lvVerTypeInfo, typeInfo(TI_STRUCT, copyBlkClass))
                && !fgCurrentlyInUseArgTemps->testBit(lclNum))
            {
                tmp = (unsigned) lclNum;
                found = true;
                JITDUMP("reusing outgoing struct arg");
                break;
            }
        }
        NEXT_HBV_BIT_SET;
    }

    // Create the CopyBlk tree and insert it.
    if (!found)
    {
        // Get a new temp
        // Here We don't need unsafe value cls check, since the addr of this temp is used only in copyblk.
        tmp = lvaGrabTemp(true DEBUGARG("by-value struct argument"));
        lvaSetStruct(tmp, copyBlkClass, false);
        fgOutgoingArgTemps->setBit(tmp);
    }

    fgCurrentlyInUseArgTemps->setBit(tmp);

    // TYP_SIMD structs should not be enregistered, since ABI requires it to be
    // allocated on stack and address of it needs to be passed.
    if (lclVarIsSIMDType(tmp))
    {
        lvaSetVarDoNotEnregister(tmp DEBUGARG(DNER_IsStruct));
    }

    // Create a reference to the temp
    GenTreePtr  dest = gtNewLclvNode(tmp, lvaTable[tmp].lvType);
    dest->gtFlags |= (GTF_DONT_CSE | GTF_VAR_DEF);  // This is a def of the local, "entire" by construction.
    dest = gtNewOperNode(GT_ADDR, TYP_BYREF, dest);
    lvaTable[tmp].incRefCnts(compCurBB->getBBWeight(this), this);

    GenTreePtr  src;
    if (argx->gtOper == GT_OBJ)
    {
        src = argx->gtOp.gtOp1;
    }
    else
    {
        argx->gtFlags |= GTF_DONT_CSE;
        src = gtNewOperNode(GT_ADDR, TYP_BYREF, argx);
    }

    // Copy the valuetype to the temp
    GenTreePtr copyBlk = gtNewCpObjNode(dest, src, copyBlkClass, false);
    copyBlk = fgMorphCopyBlock(copyBlk);

#if FEATURE_FIXED_OUT_ARGS

    // Do the copy early, and evalute the temp later (see EvalArgsToTemps)
    // When on Unix create LCL_FLD for structs passed in more than one registers. See fgMakeTmpArgNode
    GenTreePtr arg = copyBlk;

#else // FEATURE_FIXED_OUT_ARGS

    // Structs are always on the stack, and thus never need temps
    // so we have to put the copy and temp all into one expression
    GenTreePtr arg = fgMakeTmpArgNode(
        tmp
        FEATURE_UNIX_AMD64_STRUCT_PASSING_ONLY_ARG(structDescPtr->passedInRegisters));

    // Change the expression to "(tmp=val),tmp"
    arg = gtNewOperNode(GT_COMMA, arg->TypeGet(), copyBlk, arg);

#endif // FEATURE_FIXED_OUT_ARGS

    args->gtOp.gtOp1 = arg;
    call->fgArgInfo->EvalToTmp(argIndex, tmp, arg);

    return;
}

#ifdef _TARGET_ARM_
// See declaration for specification comment.
void                Compiler::fgAddSkippedRegsInPromotedStructArg(LclVarDsc* varDsc,
                                                                  unsigned   firstArgRegNum,
                                                                  regMaskTP* pArgSkippedRegMask)
{
    assert(varDsc->lvPromoted);
    // There's no way to do these calculations without breaking abstraction and assuming that
    // integer register arguments are consecutive ints.  They are on ARM.

    // To start, figure out what register contains the last byte of the first argument.
    LclVarDsc* firstFldVarDsc = &lvaTable[varDsc->lvFieldLclStart];
    unsigned lastFldRegOfLastByte = (firstFldVarDsc->lvFldOffset + firstFldVarDsc->lvExactSize - 1) / TARGET_POINTER_SIZE;;

    // Now we're keeping track of the register that the last field ended in; see what registers
    // subsequent fields start in, and whether any are skipped.
    // (We assume here the invariant that the fields are sorted in offset order.)
    for (unsigned fldVarOffset = 1; fldVarOffset < varDsc->lvFieldCnt; fldVarOffset++)
    {
        unsigned fldVarNum = varDsc->lvFieldLclStart + fldVarOffset;
        LclVarDsc* fldVarDsc = &lvaTable[fldVarNum];
        unsigned fldRegOffset = fldVarDsc->lvFldOffset / TARGET_POINTER_SIZE;
        assert(fldRegOffset >= lastFldRegOfLastByte); // Assuming sorted fields.
        // This loop should enumerate the offsets of any registers skipped.
        // Find what reg contains the last byte:
        // And start at the first register after that.  If that isn't the first reg of the current
        for (unsigned skippedRegOffsets = lastFldRegOfLastByte + 1; skippedRegOffsets < fldRegOffset; skippedRegOffsets++)
        {
            // If the register number would not be an arg reg, we're done.
            if (firstArgRegNum + skippedRegOffsets >= MAX_REG_ARG) return;
            *pArgSkippedRegMask |= genRegMask(regNumber(firstArgRegNum + skippedRegOffsets));
        }
        lastFldRegOfLastByte = (fldVarDsc->lvFldOffset + fldVarDsc->lvExactSize - 1) / TARGET_POINTER_SIZE;
    }
}

#endif // _TARGET_ARM_


/*****************************************************************************
 *
 *  The companion to impFixupCallStructReturn.  Now that the importer is done
 *  and we no longer care as much about the declared return type, change to
 *  precomputed native return type (at least for architectures that don't
 *  always use return buffers for structs).
 *
 */
void                Compiler::fgFixupStructReturn(GenTreePtr     callNode)
{
    GenTreeCall* call = callNode->AsCall();
    bool callHasRetBuffArg = call->HasRetBufArg();

    if (!callHasRetBuffArg && varTypeIsStruct(call))
    {
#ifdef _TARGET_ARM_
        if (call->gtCall.IsVarargs() || !IsHfa(call))
#endif 
        {
            // Now that we are past the importer, re-type this node so the register predictor does
            // the right thing
            call->gtType = genActualType((var_types)call->gtCall.gtReturnType);
        }
    }

#ifdef _TARGET_ARM_
    // Either we don't have a struct now or if struct, then it is HFA returned in regs.
    assert(!varTypeIsStruct(call) || (IsHfa(call) && !callHasRetBuffArg));
#elif defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
    // Either we don't have a struct now or if struct, then it is a struct returned in regs or in return buffer.
    assert(!varTypeIsStruct(call) || call->HasMultiRegRetVal() || callHasRetBuffArg);
#else 
    // No more struct returns
    assert(call->TypeGet() != TYP_STRUCT);
#endif

#if !defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
    // If it was a struct return, it has been transformed into a call
    // with a return buffer (that returns TYP_VOID) or into a return
    // of a primitive/enregisterable type
    assert(!callHasRetBuffArg || (call->TypeGet() == TYP_VOID));
#endif 
}


/*****************************************************************************
 *
 *  A little helper used to rearrange nested commutative operations. The
 *  effect is that nested associative, commutative operations are transformed
 *  into a 'left-deep' tree, i.e. into something like this:
 *
 *      (((a op b) op c) op d) op...
 */

#if REARRANGE_ADDS

void                Compiler::fgMoveOpsLeft(GenTreePtr tree)
{
    GenTreePtr op1;
    GenTreePtr op2;
    genTreeOps oper;

    do
    {
        op1  = tree->gtOp.gtOp1;
        op2  = tree->gtOp.gtOp2;
        oper = tree->OperGet();

        noway_assert(GenTree::OperIsCommutative(oper));
        noway_assert(oper == GT_ADD || oper == GT_XOR || oper == GT_OR ||
                     oper == GT_AND || oper == GT_MUL);
        noway_assert(!varTypeIsFloating(tree->TypeGet()) || !opts.genFPorder);
        noway_assert(oper == op2->gtOper);

        // Commutativity doesn't hold if overflow checks are needed

        if (tree->gtOverflowEx() || op2->gtOverflowEx())
            return;

        if (gtIsActiveCSE_Candidate(op2))
        {
            // If we have marked op2 as a CSE candidate,
            // we can't perform a commutative reordering
            // because any value numbers that we computed for op2
            // will be incorrect after performing a commutative reordering
            //
            return;
        }

        if (oper == GT_MUL && (op2->gtFlags & GTF_MUL_64RSLT))
            return;

        // Check for GTF_ADDRMODE_NO_CSE flag on add/mul Binary Operators
        if (    ((oper == GT_ADD) || (oper == GT_MUL))
             && ((tree->gtFlags & GTF_ADDRMODE_NO_CSE) != 0)               )
        {
            return;
        }

        if ( (tree->gtFlags | op2->gtFlags) & GTF_BOOLEAN )
        {
            // We could deal with this, but we were always broken and just hit the assert
            // below regarding flags, which means it's not frequent, so will just bail out.
            // See #195514
            return;
        }

        noway_assert(!tree->gtOverflowEx() && !op2->gtOverflowEx());

        GenTreePtr      ad1 = op2->gtOp.gtOp1;
        GenTreePtr      ad2 = op2->gtOp.gtOp2;

        // Compiler::optOptimizeBools() can create GT_OR of two GC pointers yeilding a GT_INT
        // We can not reorder such GT_OR trees
        //
        if (varTypeIsGC(ad1->TypeGet()) != varTypeIsGC(op2->TypeGet()))
            break;

        /* Change "(x op (y op z))" to "(x op y) op z" */
        /* ie.    "(op1 op (ad1 op ad2))" to "(op1 op ad1) op ad2" */

        GenTreePtr new_op1 = op2;

        new_op1->gtOp.gtOp1     = op1;
        new_op1->gtOp.gtOp2     = ad1;
        
        /* Change the flags. */

        // Make sure we arent throwing away any flags
        noway_assert((new_op1->gtFlags & ~(
            GTF_MAKE_CSE |
            GTF_DONT_CSE | // It is ok that new_op1->gtFlags contains GTF_DONT_CSE flag.
            GTF_REVERSE_OPS | // The reverse ops flag also can be set, it will be re-calculated 
            GTF_NODE_MASK|GTF_ALL_EFFECT|GTF_UNSIGNED)) == 0);

        new_op1->gtFlags = (new_op1->gtFlags & (GTF_NODE_MASK | GTF_DONT_CSE)) | // Make sure we propagate GTF_DONT_CSE flag.
                           (op1->gtFlags & GTF_ALL_EFFECT)  |
                           (ad1->gtFlags & GTF_ALL_EFFECT);

        /* Retype new_op1 if it has not/become a GC ptr. */

        if      (varTypeIsGC(op1->TypeGet()))
        {
            noway_assert((varTypeIsGC(tree->TypeGet()) && op2->TypeGet() == TYP_I_IMPL && oper == GT_ADD) || // byref(ref + (int+int))
                         (varTypeIsI (tree->TypeGet()) && op2->TypeGet() == TYP_I_IMPL && oper == GT_OR)); // int(gcref | int(gcref|intval))

            new_op1->gtType = tree->gtType;
        }
        else if (varTypeIsGC(ad2->TypeGet()))
        {
            // Neither ad1 nor op1 are GC. So new_op1 isnt either
            noway_assert(op1->gtType == TYP_I_IMPL && ad1->gtType == TYP_I_IMPL);
            new_op1->gtType = TYP_I_IMPL;
        }

        // If new_op1 is a new expression. Assign it a new unique value number.
        // vnStore is null before the ValueNumber phase has run
        if (vnStore != nullptr)
        {
            // We can only keep the old value number on new_op1 if both op1 and ad2 
            // have the same non-NoVN value numbers. Since op is commutative, comparing 
            // only ad2 and op1 is enough.
            if ((op1->gtVNPair.GetLiberal() == ValueNumStore::NoVN) ||
                (ad2->gtVNPair.GetLiberal() == ValueNumStore::NoVN) ||
                (ad2->gtVNPair.GetLiberal() != op1->gtVNPair.GetLiberal()))
            {
                new_op1->gtVNPair.SetBoth(vnStore->VNForExpr(new_op1->TypeGet()));
            }
        }

        tree->gtOp.gtOp1 = new_op1;
        tree->gtOp.gtOp2 = ad2;

        /* If 'new_op1' is now the same nested op, process it recursively */

        if  ((ad1->gtOper == oper) && !ad1->gtOverflowEx())
            fgMoveOpsLeft(new_op1);

        /* If   'ad2'   is now the same nested op, process it
         * Instead of recursion, we set up op1 and op2 for the next loop.
         */

        op1 = new_op1;
        op2 = ad2;
    }
    while ((op2->gtOper == oper) && !op2->gtOverflowEx());

    return;
}

#endif

/*****************************************************************************/

void            Compiler::fgSetRngChkTarget(GenTreePtr  tree,
                                            bool        delay)
{
    GenTreeBoundsChk* bndsChk = nullptr;
    SpecialCodeKind kind = SCK_RNGCHK_FAIL;

#ifdef FEATURE_SIMD
    if ((tree->gtOper == GT_ARR_BOUNDS_CHECK) || (tree->gtOper == GT_SIMD_CHK))
#else // FEATURE_SIMD
    if (tree->gtOper == GT_ARR_BOUNDS_CHECK)
#endif // FEATURE_SIMD
    {
        bndsChk = tree->AsBoundsChk();
        kind = tree->gtBoundsChk.gtThrowKind;
    }
    else
    {
        noway_assert((tree->gtOper == GT_ARR_ELEM) || (tree->gtOper == GT_ARR_INDEX));
    }

#ifdef _TARGET_X86_
    unsigned callStkDepth = fgPtrArgCntCur;
#else
    // only x86 pushes args
    const unsigned callStkDepth = 0;
#endif

    if  (opts.MinOpts())
    {
        delay = false;

        // we need to initialize this field
        if (fgGlobalMorph && bndsChk != nullptr)
        {
            bndsChk->gtStkDepth = callStkDepth;
        }
    }

    if (!opts.compDbgCode)
    {
        if (delay || compIsForInlining())
        {
            /*  We delay this until after loop-oriented range check
                analysis. For now we merely store the current stack
                level in the tree node.
             */
            if (bndsChk != nullptr)
            {
                noway_assert(!bndsChk->gtIndRngFailBB || previousCompletedPhase >= PHASE_OPTIMIZE_LOOPS);
                bndsChk->gtStkDepth = callStkDepth;
            }
        }
        else
        {
            /* Create/find the appropriate "range-fail" label */

            // fgPtrArgCntCur is only valid for global morph or if we walk full stmt.
            noway_assert((bndsChk != nullptr) || fgGlobalMorph);

            unsigned stkDepth = (bndsChk != nullptr) ? bndsChk->gtStkDepth
                                                  : callStkDepth;

            BasicBlock * rngErrBlk = fgRngChkTarget(compCurBB, stkDepth, kind);

            /* Add the label to the indirection node */

            if (bndsChk != nullptr)
            {
                bndsChk->gtIndRngFailBB = gtNewCodeRef(rngErrBlk);
            }
        }
    }
}

/*****************************************************************************
 *
 *  Expand a GT_INDEX node and fully morph the child operands
 *
 *  The orginal GT_INDEX node is bashed into the GT_IND node that accesses
 *  the array element.  We expand the GT_INDEX node into a larger tree that
 *  evaluates the array base and index.  The simplest expansion is a GT_COMMA
 *  with a GT_ARR_BOUND_CHK and a GT_IND with a GTF_INX_RNGCHK flag.
 *  For complex array or index expressions one or more GT_COMMA assignments
 *  are inserted so that we only evaluate the array or index expressions once.
 *
 *  The fully expanded tree is then morphed.  This causes gtFoldExpr to
 *  perform local constant prop and reorder the constants in the tree and
 *  fold them.
 *
 *  We then parse the resulting array element expression in order to locate
 *  and label the constants and variables that occur in the tree.
 */

const int MAX_ARR_COMPLEXITY = 4;
const int MAX_INDEX_COMPLEXITY = 4;

GenTreePtr          Compiler::fgMorphArrayIndex(GenTreePtr tree)
{
    noway_assert(tree->gtOper == GT_INDEX);
    GenTreeIndex* asIndex = tree->AsIndex();

    var_types  elemTyp  = tree->TypeGet();
    unsigned   elemSize = tree->gtIndex.gtIndElemSize;
    CORINFO_CLASS_HANDLE elemStructType = tree->gtIndex.gtStructElemClass;

    noway_assert(elemTyp != TYP_STRUCT || elemStructType != nullptr);

#ifdef FEATURE_SIMD
    if (featureSIMD && varTypeIsStruct(elemTyp) && elemSize <= getSIMDVectorRegisterByteLength())
    {
        // If this is a SIMD type, this is the point at which we lose the type information,
        // so we need to set the correct type on the GT_IND.
        // (We don't care about the base type here, so we only check, but don't retain, the return value).
        unsigned simdElemSize = 0;
        if (getBaseTypeAndSizeOfSIMDType(elemStructType, &simdElemSize) != TYP_UNKNOWN)
        {
            assert(simdElemSize == elemSize);
            elemTyp = getSIMDTypeForSize(elemSize);
            // This is the new type of the node.
            tree->gtType = elemTyp;
            // Now set elemStructType to null so that we don't confuse value numbering.
            elemStructType = nullptr;
        }
    }
#endif // FEATURE_SIMD

    GenTreePtr arrRef   = asIndex->Arr();
    GenTreePtr index    = asIndex->Index();

    // Set up the the array length's offset into lenOffs
    // And    the the first element's offset into elemOffs
    ssize_t  lenOffs;
    ssize_t  elemOffs;
    if (tree->gtFlags & GTF_INX_STRING_LAYOUT)
    {
        lenOffs  = offsetof(CORINFO_String, stringLen);
        elemOffs = offsetof(CORINFO_String, chars);
        tree->gtFlags &= ~GTF_INX_STRING_LAYOUT;    // Clear this flag as it is used for GTF_IND_VOLATILE
    }
    else if (tree->gtFlags & GTF_INX_REFARR_LAYOUT)
    {
        lenOffs  = offsetof(CORINFO_RefArray, length);
        elemOffs = eeGetEEInfo()->offsetOfObjArrayData;
    }
    else // We have a standard array
    {
        lenOffs  = offsetof(CORINFO_Array, length);
        elemOffs = offsetof(CORINFO_Array, u1Elems);
    }

    bool  chkd = ((tree->gtFlags & GTF_INX_RNGCHK) != 0);     // if false, range checking will be disabled
    bool  nCSE = ((tree->gtFlags & GTF_DONT_CSE  ) != 0);

    GenTreePtr arrRefDefn = nullptr;    // non-NULL if we need to allocate a temp for the arrRef expression
    GenTreePtr indexDefn  = nullptr;    // non-NULL if we need to allocate a temp for the index expression
    GenTreePtr bndsChk    = nullptr;

    // If we're doing range checking, introduce a GT_ARR_BOUNDS_CHECK node for the address.
    if (chkd)
    {
        GenTreePtr arrRef2 = nullptr;    // The second copy will be used in array address expression
        GenTreePtr index2  = nullptr;

        // If the arrRef expression involves an assignment, a call or reads from global memory,
        // then we *must* allocate a temporary in which to "localize" those values,
        // to ensure that the same values are used in the bounds check and the actual
        // dereference.
        // Also we allocate the temporary when the arrRef is sufficiently complex/expensive.
        //
        if ((arrRef->gtFlags & (GTF_ASG|GTF_CALL|GTF_GLOB_REF)) || gtComplexityExceeds(&arrRef, MAX_ARR_COMPLEXITY))
        {
            unsigned arrRefTmpNum = lvaGrabTemp(true DEBUGARG("arr expr"));
            arrRefDefn = gtNewTempAssign(arrRefTmpNum, arrRef);
            arrRef     = gtNewLclvNode(arrRefTmpNum, arrRef->TypeGet());
            arrRef2    = gtNewLclvNode(arrRefTmpNum, arrRef->TypeGet());
        }
        else
        {
            arrRef2 = gtCloneExpr(arrRef);
            noway_assert(arrRef2 != nullptr);
        }

        // If the index expression involves an assignment, a call or reads from global memory,
        // we *must* allocate a temporary in which to "localize" those values,
        // to ensure that the same values are used in the bounds check and the actual
        // dereference.
        // Also we allocate the temporary when the index is sufficiently complex/expensive.
        //
        if ((index->gtFlags & (GTF_ASG|GTF_CALL|GTF_GLOB_REF)) || gtComplexityExceeds(&index, MAX_ARR_COMPLEXITY))
        {
            unsigned indexTmpNum = lvaGrabTemp(true DEBUGARG("arr expr"));
            indexDefn = gtNewTempAssign(indexTmpNum, index);
            index     = gtNewLclvNode(indexTmpNum, index->TypeGet());
            index2    = gtNewLclvNode(indexTmpNum, index->TypeGet());
        }
        else
        {
            index2 = gtCloneExpr(index);
            noway_assert(index2 != nullptr);
        }

        // Next introduce a GT_ARR_BOUNDS_CHECK node
        var_types bndsChkType = TYP_INT;  // By default, try to use 32-bit comparison for array bounds check.

#ifdef _TARGET_64BIT_
        // The CLI Spec allows an array to be indexed by either an int32 or a native int.  In the case
        // of a 64 bit architecture this means the array index can potentially be a TYP_LONG, so for this case, 
        // the comparison will have to be widen to 64 bits.
        if (index->TypeGet() == TYP_I_IMPL)
        {
            bndsChkType = TYP_I_IMPL;
        }
#endif // _TARGET_64BIT_

        GenTree* arrLen = new (this, GT_ARR_LENGTH) GenTreeArrLen(TYP_INT, arrRef, (int)lenOffs);

        if (bndsChkType != TYP_INT)
        {
            arrLen = gtNewCastNode(bndsChkType, arrLen, bndsChkType);
        }

        GenTreeBoundsChk* arrBndsChk    = new (this, GT_ARR_BOUNDS_CHECK) GenTreeBoundsChk(GT_ARR_BOUNDS_CHECK, TYP_VOID, arrLen, index, SCK_RNGCHK_FAIL);

        bndsChk = arrBndsChk;

        // Make sure to increment ref-counts if already ref-counted.
        if (lvaLocalVarRefCounted)
        {
            lvaRecursiveIncRefCounts(index);
            lvaRecursiveIncRefCounts(arrRef);
        }

        // Now we'll switch to using the second copies for arrRef and index
        // to compute the address expression

        arrRef = arrRef2;
        index  = index2;
    }

    // Create the "addr" which is "*(arrRef + ((index * elemSize) + elemOffs))"

    GenTreePtr addr;

    // Widen 'index' on 64-bit targets
#ifdef _TARGET_64BIT_
    if (index->TypeGet() != TYP_I_IMPL)
    {
        if (index->OperGet() == GT_CNS_INT)
        {
            index->gtType = TYP_I_IMPL;
        }
        else
        {
            index = gtNewCastNode(TYP_I_IMPL, index, TYP_I_IMPL);
        }
    }
#endif // _TARGET_64BIT_

    /* Scale the index value if necessary */
    if  (elemSize > 1)
    {
        GenTreePtr size = gtNewIconNode(elemSize, TYP_I_IMPL);

        // Fix 392756 WP7 Crossgen
        //
        // During codegen optGetArrayRefScaleAndIndex() makes the assumption that op2 of a GT_MUL node
        // is a constant and is not capable of handling CSE'ing the elemSize constant into a lclvar.
        // Hence to prevent the constant from becoming a CSE we mark it as NO_CSE.
        //
        size->gtFlags |= GTF_DONT_CSE;

        /* Multiply by the array element size */
        addr = gtNewOperNode(GT_MUL, TYP_I_IMPL, index, size);
    }
    else
    {
        addr = index;
    }

    /* Add the object ref to the element's offset */

    addr = gtNewOperNode(GT_ADD, TYP_BYREF, arrRef, addr);

    /* Add the first element's offset */

    GenTreePtr cns = gtNewIconNode(elemOffs, TYP_I_IMPL);

    addr = gtNewOperNode(GT_ADD, TYP_BYREF, addr, cns);

#if SMALL_TREE_NODES
    assert(tree->gtFlags & GTF_NODE_LARGE);
#endif

    // Change the orginal GT_INDEX node into a GT_IND node
    tree->SetOper(GT_IND);

    // If the index node is a floating-point type, notify the compiler
    // we'll potentially use floating point registers at the time of codegen.
    if (varTypeIsFloating(tree->gtType))
    {
        this->compFloatingPointUsed = true;
    }

    // We've now consumed the GTF_INX_RNGCHK, and the node
    // is no longer a GT_INDEX node.
    tree->gtFlags &= ~GTF_INX_RNGCHK;

    tree->gtOp.gtOp1 = addr;

    // This is an array index expression.
    tree->gtFlags |= GTF_IND_ARR_INDEX;

    /* An indirection will cause a GPF if the address is null */
    tree->gtFlags |= GTF_EXCEPT;

    if  (nCSE)
        tree->gtFlags |= GTF_DONT_CSE;

    // Store information about it.
    GetArrayInfoMap()->Set(tree, ArrayInfo(elemTyp, elemSize, (int) elemOffs, elemStructType));

    // Remember this 'indTree' that we just created, as we still need to attach the fieldSeq information to it.

    GenTreePtr indTree = tree;

    // Did we create a bndsChk tree?
    if  (bndsChk)
    {
        // Use a GT_COMMA node to prepend the array bound check
        //
        tree = gtNewOperNode(GT_COMMA, elemTyp, bndsChk, tree);

        /* Mark the indirection node as needing a range check */
        fgSetRngChkTarget(bndsChk);
    }

    if (indexDefn != nullptr)
    {
        // Use a GT_COMMA node to prepend the index assignment
        //
        tree = gtNewOperNode(GT_COMMA, tree->TypeGet(), indexDefn, tree);
    }
    if (arrRefDefn != nullptr)
    {
        // Use a GT_COMMA node to prepend the arRef assignment
        //
        tree = gtNewOperNode(GT_COMMA, tree->TypeGet(), arrRefDefn, tree);
    }

    // Currently we morph the tree to perform some folding operations prior 
    // to attaching fieldSeq info and labeling constant array index contributions
    // 
    fgMorphTree(tree);

    // Ideally we just want to proceed to attaching fieldSeq info and labeling the 
    // constant array index contributions, but the morphing operation may have changed 
    // the 'tree' into something that now unconditionally throws an exception.
    //
    // In such case the gtEffectiveVal could be a new tree or it's gtOper could be modified
    // or it could be left unchanged.  If it is unchanged then we should not return, 
    // instead we should proceed to attaching fieldSeq info, etc...
    // 
    GenTreePtr arrElem = tree->gtEffectiveVal();

    if (fgIsCommaThrow(tree))
    {
        if ((arrElem != indTree) ||          // A new tree node may have been created
            (indTree->OperGet() != GT_IND))  // The GT_IND may have been changed to a GT_CNS_INT
        {
            return tree;     // Just return the Comma-Throw, don't try to attach the fieldSeq info, etc..
        }
    }

    assert(!fgGlobalMorph || (arrElem->gtFlags & GTF_MORPHED));

    addr = arrElem->gtOp.gtOp1;

    assert(addr->TypeGet() == TYP_BYREF);

    GenTreePtr cnsOff = nullptr;
    if (addr->OperGet() == GT_ADD)
    {
        if (addr->gtOp.gtOp2->gtOper == GT_CNS_INT)
        {
            cnsOff = addr->gtOp.gtOp2;
            addr   = addr->gtOp.gtOp1;
        }

        while ((addr->OperGet() == GT_ADD) || (addr->OperGet() == GT_SUB))
        {
            assert(addr->TypeGet() == TYP_BYREF);
            GenTreePtr index = addr->gtOp.gtOp2;

            // Label any constant array index contributions with #ConstantIndex and any LclVars with GTF_VAR_ARR_INDEX
            index->LabelIndex(this);

            addr  = addr->gtOp.gtOp1;
        }
        assert(addr->TypeGet() == TYP_REF);
    }
    else if (addr->OperGet() == GT_CNS_INT)
    {
         cnsOff = addr;
    }

    FieldSeqNode* firstElemFseq = GetFieldSeqStore()->CreateSingleton(FieldSeqStore::FirstElemPseudoField);

    if ((cnsOff != nullptr) && (cnsOff->gtIntCon.gtIconVal == elemOffs))
    {
        // Assign it the [#FirstElem] field sequence
        //
        cnsOff->gtIntCon.gtFieldSeq = firstElemFseq;
    }
    else  //  We have folded the first element's offset with the index expression
    {
        // Build the [#ConstantIndex, #FirstElem] field sequence
        //
        FieldSeqNode* constantIndexFseq = GetFieldSeqStore()->CreateSingleton(FieldSeqStore::ConstantIndexPseudoField);
        FieldSeqNode* fieldSeq          = GetFieldSeqStore()->Append(constantIndexFseq, firstElemFseq);

        if (cnsOff == nullptr)   // It must have folded into a zero offset
        {
            // Record in the general zero-offset map.
            GetZeroOffsetFieldMap()->Set(addr, fieldSeq);
        }
        else
        {
            cnsOff->gtIntCon.gtFieldSeq = fieldSeq;
        }
    }

    return tree;
}

#ifdef _TARGET_X86_
/*****************************************************************************
 *
 *  Wrap fixed stack arguments for varargs functions to go through varargs
 *  cookie to access them, except for the cookie itself.
 *
 * Non-x86 platforms are allowed to access all arguments directly
 * so we don't need this code.
 *
 */
GenTreePtr          Compiler::fgMorphStackArgForVarArgs(unsigned lclNum, var_types varType, unsigned lclOffs)
{
    /* For the fixed stack arguments of a varargs function, we need to go
        through the varargs cookies to access them, except for the
        cookie itself */

    LclVarDsc * varDsc = &lvaTable[lclNum];

    if (varDsc->lvIsParam && !varDsc->lvIsRegArg &&
        lclNum != lvaVarargsHandleArg)
    {
        // Create a node representing the local pointing to the base of the args
        GenTreePtr ptrArg = gtNewOperNode(GT_SUB, TYP_I_IMPL,
                                            gtNewLclvNode(lvaVarargsBaseOfStkArgs, TYP_I_IMPL),
                                            gtNewIconNode(varDsc->lvStkOffs 
                                                        - codeGen->intRegState.rsCalleeRegArgNum*sizeof(void*)
                                                        + lclOffs));

        // Access the argument through the local
        GenTreePtr tree = gtNewOperNode(GT_IND, varType, ptrArg);
        tree->gtFlags |= GTF_IND_TGTANYWHERE;

        if (varDsc->lvAddrExposed)
        {
            tree->gtFlags |= GTF_GLOB_REF;
        }

        return fgMorphTree(tree);
    }

    return NULL;
}
#endif

/*****************************************************************************
 *
 *  Transform the given GT_LCL_VAR tree for code generation.
 */

GenTreePtr          Compiler::fgMorphLocalVar(GenTreePtr tree)
{
    noway_assert(tree->gtOper == GT_LCL_VAR);

    unsigned    lclNum  = tree->gtLclVarCommon.gtLclNum;
    var_types   varType = lvaGetRealType(lclNum);
    LclVarDsc * varDsc = &lvaTable[lclNum];

    if (varDsc->lvAddrExposed)
    {
        tree->gtFlags |= GTF_GLOB_REF;
    }

#ifdef _TARGET_X86_
    if (info.compIsVarArgs)
    {
        GenTreePtr newTree = fgMorphStackArgForVarArgs(lclNum, varType, 0);
        if (newTree != NULL)
            return newTree;
    }
#endif // _TARGET_X86_

    /* If not during the global morphing phase bail */

    if (!fgGlobalMorph)
        return tree;

    bool varAddr = (tree->gtFlags & GTF_DONT_CSE) != 0;

    noway_assert(!(tree->gtFlags & GTF_VAR_DEF) || varAddr); // GTF_VAR_DEF should always imply varAddr

    if (!varAddr                          &&
        varTypeIsSmall(varDsc->TypeGet()) &&
        varDsc->lvNormalizeOnLoad())
    {
#if LOCAL_ASSERTION_PROP
        /* Assertion prop can tell us to omit adding a cast here */
        if (optLocalAssertionProp &&
            optAssertionIsSubrange(tree, varType, apFull) != NO_ASSERTION_INDEX)
        {
            return tree;
        }
#endif
        /* Small-typed arguments and aliased locals are normalized on load.
           Other small-typed locals are normalized on store.
           Also, under the debugger as the debugger could write to the variable.
           If this is one of the former, insert a narrowing cast on the load.
                   ie. Convert: var-short --> cast-short(var-int) */

        tree->gtType = TYP_INT;
        fgMorphTreeDone(tree);
        tree = gtNewCastNode(TYP_INT, tree, varType);
        fgMorphTreeDone(tree);
        return tree;
    }

    return tree;
}


/*****************************************************************************
  Grab a temp for big offset morphing.
  This method will grab a new temp if no temp of this "type" has been created.
  Or it will return the same cached one if it has been created.
*/
unsigned            Compiler::fgGetBigOffsetMorphingTemp(var_types type)
{
    unsigned lclNum = fgBigOffsetMorphingTemps[type];

    if (lclNum == BAD_VAR_NUM) {
        // We haven't created a temp for this kind of type. Create one now.
        lclNum = lvaGrabTemp(false DEBUGARG("Big Offset Morphing"));
        fgBigOffsetMorphingTemps[type] = lclNum;
    }
    else {
        // We better get the right type.
        noway_assert(lvaTable[lclNum].TypeGet() == type);
    }

    noway_assert(lclNum != BAD_VAR_NUM);
    return lclNum;
}


/*****************************************************************************
 *
 *  Transform the given GT_FIELD tree for code generation.
 */

GenTreePtr          Compiler::fgMorphField(GenTreePtr tree, MorphAddrContext* mac)
 {
     assert(tree->gtOper == GT_FIELD);

     noway_assert(tree->gtFlags & GTF_GLOB_REF);

     CORINFO_FIELD_HANDLE  symHnd    = tree->gtField.gtFldHnd;
     unsigned              fldOffset = tree->gtField.gtFldOffset;
     GenTreePtr            objRef    = tree->gtField.gtFldObj;
     bool                  fieldMayOverlap = false;
     if (tree->gtField.gtFldMayOverlap)
     {
          fieldMayOverlap = true;
          // Reset the flag because we may reuse the node.
          tree->gtField.gtFldMayOverlap = false;
     }

#ifdef FEATURE_SIMD
     // if this field belongs to simd struct, tranlate it to simd instrinsic.
     if (mac == nullptr || mac->m_kind != MACK_Addr)
     {
         GenTreePtr newTree = fgMorphFieldToSIMDIntrinsicGet(tree);
         if (newTree != tree)
         {
             newTree = fgMorphSmpOp(newTree);
             return newTree;
         }
     }
     else if (objRef != nullptr && objRef->OperGet() == GT_ADDR && objRef->OperIsSIMD())
     {
         // We have a field of an SIMD intrinsic in an address-taken context.
         // We need to copy the SIMD result to a temp, and take the field of that.
         GenTree* copy = fgCopySIMDNode(objRef->gtOp.gtOp1->AsSIMD());
         objRef->gtOp.gtOp1 = copy;
     }
#endif
     
     /* Is this an instance data member? */

     if  (objRef)
     {
        GenTreePtr     addr;

        if (tree->gtFlags & GTF_IND_TLS_REF)
            NO_WAY("instance field can not be a TLS ref.");

        /* We'll create the expression "*(objRef + mem_offs)" */

        noway_assert(varTypeIsGC(objRef->TypeGet()) ||
                           objRef->TypeGet() == TYP_I_IMPL);

        // An optimization for Contextful classes:
        // we unwrap the proxy when we have a 'this reference'
        if (info.compIsContextful &&
            info.compUnwrapContextful &&
            impIsThis(objRef))
        {
            objRef = fgUnwrapProxy(objRef);
        }

        /*
            Now we have a tree like this:

                                  +--------------------+
                                  |      GT_FIELD      |   tree
                                  +----------+---------+
                                             |
                              +--------------+-------------+
                              |   tree->gtField.gtFldObj   |
                              +--------------+-------------+


            We want to make it like this (when fldOffset is <= MAX_UNCHECKED_OFFSET_FOR_NULL_OBJECT):

                                  +--------------------+
                                  |   GT_IND/GT_OBJ    |   tree
                                  +---------+----------+
                                            |
                                            |
                                  +---------+----------+
                                  |       GT_ADD       |   addr
                                  +---------+----------+
                                            |
                                          /   \
                                        /       \
                                      /           \
                         +-------------------+  +----------------------+
                         |       objRef      |  |     fldOffset        |
                         |                   |  | (when fldOffset !=0) |
                         +-------------------+  +----------------------+


            or this (when fldOffset is > MAX_UNCHECKED_OFFSET_FOR_NULL_OBJECT):


                                  +--------------------+
                                  |   GT_IND/GT_OBJ    |   tree
                                  +----------+---------+
                                             |
                                  +----------+---------+
                                  |       GT_COMMA     |  comma2
                                  +----------+---------+
                                             |
                                            / \
                                          /     \
                                        /         \
                                      /             \
                 +---------+----------+               +---------+----------+
           comma |      GT_COMMA      |               |  "+" (i.e. GT_ADD) |   addr
                 +---------+----------+               +---------+----------+
                           |                                     |
                         /   \                                  /  \
                       /       \                              /      \
                     /           \                          /          \
         +-----+-----+             +-----+-----+      +---------+   +-----------+
     asg |  GT_ASG   |         ind |   GT_IND  |      |  tmpLcl |   | fldOffset |
         +-----+-----+             +-----+-----+      +---------+   +-----------+
               |                         |
              / \                        |
            /     \                      |
          /         \                    |
   +-----+-----+   +-----+-----+   +-----------+
   |   tmpLcl  |   |   objRef  |   |   tmpLcl  |
   +-----------+   +-----------+   +-----------+


        */

        var_types             objRefType = objRef->TypeGet();

        GenTreePtr            comma      = NULL;

        bool addedExplicitNullCheck = false;

        // NULL mac means we encounter the GT_FIELD first.  This denotes a dereference of the field,
        // and thus is equivalent to a MACK_Ind with zero offset.
        MorphAddrContext defMAC(MACK_Ind);
        if (mac == NULL) mac = &defMAC;

        // This flag is set to enable the "conservative" style of explicit null-check insertion.
        // This means that we insert an explicit null check whenever we create byref by adding a
        // constant offset to a ref, in a MACK_Addr context (meaning that the byref is not immediately
        // dereferenced).  The alternative is "aggressive", which would not insert such checks (for
        // small offsets); in this plan, we would transfer some null-checking responsibility to
        // callee's of methods taking byref parameters.  They would have to add explicit null checks
        // when creating derived byrefs from argument byrefs by adding constants to argument byrefs, in
        // contexts where the resulting derived byref is not immediately dereferenced (or if the offset is too
        // large).  To make the "aggressive" scheme work, however, we'd also have to add explicit derived-from-null
        // checks for byref parameters to "external" methods implemented in C++, and in P/Invoke stubs.
        /// This is left here to point out how to implement it.
#define CONSERVATIVE_NULL_CHECK_BYREF_CREATION 1

        // If the objRef is a GT_ADDR node, it, itself, never requires null checking.  The expression
        // whose address is being taken is either a local or static variable, whose address is necessarily
        // non-null, or else it is a field dereference, which will do its own bounds checking if necessary.
        if (objRef->gtOper != GT_ADDR
            && ((mac->m_kind == MACK_Addr || mac->m_kind == MACK_Ind)
                && (!mac->m_allConstantOffsets
                    || fgIsBigOffset(mac->m_totalOffset + fldOffset)
#if CONSERVATIVE_NULL_CHECK_BYREF_CREATION
                    || (mac->m_kind == MACK_Addr && (mac->m_totalOffset + fldOffset > 0))
#else
                    || (objRef->gtType == TYP_BYREF && mac->m_kind == MACK_Addr && (mac->m_totalOffset + fldOffset > 0))
#endif
                    )))
        {
#ifdef DEBUG
            if (verbose)
            {
                printf("Before explicit null check morphing:\n");
                gtDispTree(tree);
            }
#endif

            //
            // Create the "comma" subtree
            //
            GenTreePtr     asg = NULL;
            GenTreePtr     nullchk;

            unsigned lclNum;

            if (objRef->gtOper != GT_LCL_VAR)
            {
                lclNum = fgGetBigOffsetMorphingTemp(genActualType(objRef->TypeGet()));

                // Create the "asg" node
                asg    = gtNewTempAssign(lclNum, objRef);
            }
            else
            {
                lclNum = objRef->gtLclVarCommon.gtLclNum;
            }

            // Create the "nullchk" node
            nullchk = gtNewOperNode(GT_NULLCHECK,
                                    TYP_BYTE,  // Make it TYP_BYTE so we only deference it for 1 byte.
                                    gtNewLclvNode(lclNum, objRefType));
            nullchk->gtFlags |= GTF_DONT_CSE;     // Don't try to create a CSE for these TYP_BYTE indirections

            /* An indirection will cause a GPF if the address is null */
            nullchk->gtFlags |= GTF_EXCEPT;

            if (asg)
            {
                // Create the "comma" node.
                comma  = gtNewOperNode(GT_COMMA,
                                       TYP_VOID, // We don't want to return anything from this "comma" node.
                                                 // Set the type to TYP_VOID, so we can select "cmp" instruction
                                                 // instead of "mov" instruction later on.
                                       asg,
                                       nullchk);
            }
            else
            {
                comma = nullchk;
            }

            addr = gtNewLclvNode(lclNum, objRefType);     // Use "tmpLcl" to create "addr" node.

            addedExplicitNullCheck = true;
        }
        else if  (fldOffset == 0)
        {
            // Generate the "addr" node.
            addr = objRef;
            FieldSeqNode* fieldSeq = fieldMayOverlap ? FieldSeqStore::NotAField() : GetFieldSeqStore()->CreateSingleton(symHnd);
            GetZeroOffsetFieldMap()->Set(addr, fieldSeq);
        }
        else
        {
            addr = objRef;
        }

#ifdef FEATURE_READYTORUN_COMPILER
        if (tree->gtField.gtFieldLookup.addr != nullptr)
        {
            GenTreePtr baseOffset = gtNewIconEmbHndNode(tree->gtField.gtFieldLookup.addr, nullptr, GTF_ICON_FIELD_HDL);

            if (tree->gtField.gtFieldLookup.accessType == IAT_PVALUE)
                baseOffset = gtNewOperNode(GT_IND, TYP_I_IMPL, baseOffset);

            addr = gtNewOperNode(GT_ADD,
                                 (var_types)(objRefType ==  TYP_I_IMPL ? TYP_I_IMPL
                                                            : TYP_BYREF),
                                 addr,
                                 baseOffset
                                );
        }
#endif
        if  (fldOffset != 0)
        {
            // Generate the "addr" node.
            /* Add the member offset to the object's address */
            FieldSeqNode* fieldSeq = fieldMayOverlap ? FieldSeqStore::NotAField() : GetFieldSeqStore()->CreateSingleton(symHnd);
            addr = gtNewOperNode(GT_ADD,
                                 (var_types)(objRefType == TYP_I_IMPL ? TYP_I_IMPL
                                                            : TYP_BYREF),
                                 addr,
                                 gtNewIconHandleNode(fldOffset,
                                                     GTF_ICON_FIELD_OFF,
                                                     fieldSeq));
        }

        // Now let's set the "tree" as a GT_IND tree.

        tree->SetOper(GT_IND);
        tree->gtOp.gtOp1 = addr;

        if (fgAddrCouldBeNull(addr))
        {
            // This indirection can cause a GPF if the address could be null.
            tree->gtFlags |= GTF_EXCEPT;
        }

        if (addedExplicitNullCheck)
        {
            //
            // Create "comma2" node and link it to "tree".
            //
            GenTreePtr comma2;
            comma2 = gtNewOperNode(GT_COMMA,
                                   addr->TypeGet(), // The type of "comma2" node is the same as the type of "addr" node.
                                   comma,
                                   addr);
            tree->gtOp.gtOp1 = comma2;
        }

#ifdef DEBUG
        if (verbose)
        {
            if (addedExplicitNullCheck) {
                printf("After adding explicit null check:\n");
                gtDispTree(tree);
            }
        }
#endif

    }
    else     /* This is a static data member */
    {
        if (tree->gtFlags & GTF_IND_TLS_REF)
        {
            // Thread Local Storage static field reference
            //
            // Field ref is a TLS 'Thread-Local-Storage' reference
            //
            // Build this tree:  IND(*) #
            //                    |
            //                   ADD(I_IMPL)
            //                   / \
            //                  /  CNS(fldOffset)
            //                 /
            //                /
            //               /
            //             IND(I_IMPL) == [Base of this DLL's TLS]
            //              |
            //             ADD(I_IMPL)
            //             / \
            //            /   CNS(IdValue*4) or MUL
            //           /                      / \
            //          IND(I_IMPL)            /  CNS(4)
            //           |                    /
            //          CNS(TLS_HDL,0x2C)    IND
            //                                |
            //                               CNS(pIdAddr)
            //
            // # Denotes the orginal node
            //
            void **    pIdAddr   = NULL;
            unsigned    IdValue  = info.compCompHnd->getFieldThreadLocalStoreID(symHnd, (void**) &pIdAddr);

            //
            // If we can we access the TLS DLL index ID value directly
            // then pIdAddr will be NULL and
            //      IdValue will be the actual TLS DLL index ID
            //
            GenTreePtr dllRef = NULL;
            if (pIdAddr == NULL)
            {
                if (IdValue != 0)
                    dllRef = gtNewIconNode(IdValue*4, TYP_I_IMPL);
            }
            else
            {
                dllRef = gtNewIconHandleNode((size_t)pIdAddr, GTF_ICON_STATIC_HDL);
                dllRef = gtNewOperNode(GT_IND, TYP_I_IMPL, dllRef);
                dllRef->gtFlags |= GTF_IND_INVARIANT;

                /* Multiply by 4 */

                dllRef = gtNewOperNode(GT_MUL, TYP_I_IMPL, dllRef, gtNewIconNode(4, TYP_I_IMPL));
            }

            #define WIN32_TLS_SLOTS (0x2C) // Offset from fs:[0] where the pointer to the slots resides

            // Mark this ICON as a TLS_HDL, codegen will use FS:[cns]

            GenTreePtr tlsRef = gtNewIconHandleNode(WIN32_TLS_SLOTS, GTF_ICON_TLS_HDL);

            tlsRef = gtNewOperNode(GT_IND, TYP_I_IMPL, tlsRef);

            if (dllRef != NULL)
            {
                /* Add the dllRef */
                tlsRef = gtNewOperNode(GT_ADD, TYP_I_IMPL, tlsRef, dllRef);
            }

            /* indirect to have tlsRef point at the base of the DLLs Thread Local Storage */
            tlsRef = gtNewOperNode(GT_IND, TYP_I_IMPL, tlsRef);

            if (fldOffset != 0)
            {
                FieldSeqNode* fieldSeq = fieldMayOverlap ? FieldSeqStore::NotAField() : GetFieldSeqStore()->CreateSingleton(symHnd);
                GenTreePtr fldOffsetNode = new(this, GT_CNS_INT) GenTreeIntCon(TYP_INT, fldOffset, fieldSeq);

                /* Add the TLS static field offset to the address */

                tlsRef = gtNewOperNode(GT_ADD, TYP_I_IMPL, tlsRef, fldOffsetNode);
            }

            // Final indirect to get to actual value of TLS static field

            tree->SetOper(GT_IND);
            tree->gtOp.gtOp1 = tlsRef;

            noway_assert(tree->gtFlags & GTF_IND_TLS_REF);
        }
        else
        {
            // Normal static field reference

            //
            // If we can we access the static's address directly
            // then pFldAddr will be NULL and
            //      fldAddr will be the actual address of the static field
            //
            void **  pFldAddr = NULL;
            void * fldAddr = info.compCompHnd->getFieldAddress(symHnd, (void**) &pFldAddr);

            if (pFldAddr == NULL)
            {
#ifdef _TARGET_64BIT_
                if (IMAGE_REL_BASED_REL32 != eeGetRelocTypeHint(fldAddr))
                {
                    // The address is not directly addressible, so force it into a
                    // constant, so we handle it properly

                    GenTreePtr addr = gtNewIconHandleNode((size_t)fldAddr, GTF_ICON_STATIC_HDL);
                    addr->gtType = TYP_I_IMPL;
                    FieldSeqNode* fieldSeq = fieldMayOverlap ? FieldSeqStore::NotAField() : GetFieldSeqStore()->CreateSingleton(symHnd);
                    addr->gtIntCon.gtFieldSeq = fieldSeq;

                    tree->SetOper(GT_IND);
                    tree->gtOp.gtOp1         = addr;

                    return fgMorphSmpOp(tree);
                }
                else
#endif // _TARGET_64BIT_
                {
                    // Only volatile could be set, and it maps over
                    noway_assert((tree->gtFlags & ~(GTF_FLD_VOLATILE | GTF_COMMON_MASK)) == 0);
                    noway_assert(GTF_FLD_VOLATILE == GTF_IND_VOLATILE);
                    tree->SetOper(GT_CLS_VAR);
                    tree->gtClsVar.gtClsVarHnd = symHnd;
                    FieldSeqNode* fieldSeq = fieldMayOverlap ? FieldSeqStore::NotAField() : GetFieldSeqStore()->CreateSingleton(symHnd);
                    tree->gtClsVar.gtFieldSeq = fieldSeq;
                }

                return tree;
            }
            else
            {
                GenTreePtr addr  = gtNewIconHandleNode((size_t)pFldAddr, GTF_ICON_STATIC_HDL);

                // There are two cases here, either the static is RVA based,
                // in which case the type of the FIELD node is not a GC type
                // and the handle to the RVA is a TYP_I_IMPL.  Or the FIELD node is
                // a GC type and the handle to it is a TYP_BYREF in the GC heap
                // because handles to statics now go into the large object heap

                var_types  handleTyp = (var_types) (varTypeIsGC(tree->TypeGet()) ? TYP_BYREF
                                                    : TYP_I_IMPL);
                GenTreePtr op1       = gtNewOperNode(GT_IND, handleTyp, addr);
                op1->gtFlags        |= GTF_IND_INVARIANT;

                tree->SetOper(GT_IND);
                tree->gtOp.gtOp1 = op1;
            }
        }
    }
    noway_assert(tree->gtOper == GT_IND);

    GenTreePtr res = fgMorphSmpOp(tree);

    if (fldOffset == 0 && res->OperGet() == GT_IND)
    {
        GenTreePtr addr = res->gtOp.gtOp1;
        // Since we don't make a constant zero to attach the field sequence to, associate it with the "addr" node.
        FieldSeqNode* fieldSeq = fieldMayOverlap ? FieldSeqStore::NotAField() : GetFieldSeqStore()->CreateSingleton(symHnd);
        fgAddFieldSeqForZeroOffset(addr, fieldSeq);
    }

    return res;

}


//------------------------------------------------------------------------------
// fgMorphCallInline: attempt to inline a call
//
// Arguments:
//    call         - call expression to inline, inline candidate
//    inlineResult - result tracking and reporting
//
// Notes:
//    Attempts to inline the call.
//
//    If successful, callee's IR is inserted in place of the call, and
//    is marked with an InlineContext.
//
//    If unsuccessful, the transformations done in anticpation of a
//    possible inline are undone, and the candidate flag on the call
//    is cleared.

void        Compiler::fgMorphCallInline(GenTreeCall* call, InlineResult* inlineResult)
{
    // The call must be a candiate for inlining.
    assert((call->gtFlags & GTF_CALL_INLINE_CANDIDATE) != 0);

    // Attempt the inline
    fgMorphCallInlineHelper(call, inlineResult);

    // We should have made up our minds one way or another....
    assert(inlineResult->IsDecided());

    // If we failed to inline, we have a bit of work to do to cleanup
    if (inlineResult->IsFailure())
    {

#ifdef DEBUG

        // Before we do any cleanup, create a failing InlineContext to
        // capture details of the inlining attempt.
        m_inlineStrategy->NewFailure(fgMorphStmt, inlineResult);

#endif

        // It was an inline candidate, but we haven't expanded it.
        if (call->gtCall.gtReturnType != TYP_VOID)
        {
            // Detach the GT_CALL tree from the original statement by
            // hanging a "nothing" node to it. Later the "nothing" node will be removed
            // and the original GT_CALL tree will be picked up by the GT_RET_EXPR node.

            noway_assert(fgMorphStmt->gtStmt.gtStmtExpr == call);
            fgMorphStmt->gtStmt.gtStmtExpr = gtNewNothingNode();
        }

        // Clear the Inline Candidate flag so we can ensure later we tried
        // inlining all candidates.
        //
        call->gtFlags &= ~GTF_CALL_INLINE_CANDIDATE;
    }
}

/*****************************************************************************
 *  Helper to attempt to inline a call
 *  Sets success/failure in inline result
 *  If success, modifies current method's IR with inlinee's IR
 *  If failed, undoes any speculative modifications to current method
 */

void Compiler::fgMorphCallInlineHelper(GenTreeCall* call, InlineResult* result)
{
    // Don't expect any surprises here.
    assert(result->IsCandidate());
    
    if (lvaCount >= MAX_LV_NUM_COUNT_FOR_INLINING)
    {
        // For now, attributing this to call site, though it's really
        // more of a budget issue (lvaCount currently includes all
        // caller and prospective callee locals). We still might be
        // able to inline other callees into this caller, or inline
        // this callee in other callers.
        result->NoteFatal(InlineObservation::CALLSITE_TOO_MANY_LOCALS);
        return;
    }

    if (call->IsVirtual())
    {
        result->NoteFatal(InlineObservation::CALLSITE_IS_VIRTUAL);
        return;
    }

    // impMarkInlineCandidate() is expected not to mark tail prefixed calls
    // and recursive tail calls as inline candidates.
    noway_assert(!call->IsTailPrefixedCall());
    noway_assert(!call->IsImplicitTailCall() || !gtIsRecursiveCall(call));

    /* If the caller's stack frame is marked, then we can't do any inlining. Period.
       Although we have checked this in impCanInline, it is possible that later IL instructions
       might cause compNeedSecurityCheck to be set. Therefore we need to check it here again.
    */

    if (opts.compNeedSecurityCheck)
    {
        result->NoteFatal(InlineObservation::CALLER_NEEDS_SECURITY_CHECK);
        return;
    }
    
    //
    // Calling inlinee's compiler to inline the method.
    //

    unsigned    startVars = lvaCount;

#ifdef DEBUG
    if (verbose)
    {
       printf("Expanding INLINE_CANDIDATE in statement ");
       printTreeID(fgMorphStmt);
       printf(" in BB%02u:\n", compCurBB->bbNum);
       gtDispTree(fgMorphStmt);
       
       // printf("startVars=%d.\n", startVars);
    }
#endif

    //
    // Invoke the compiler to inline the call.
    //
    
    fgInvokeInlineeCompiler(call, result);

    if (result->IsFailure()) 
    {
       // Undo some changes made in anticipation of inlining...

       // Zero out the used locals
       memset(lvaTable + startVars, 0, (lvaCount  - startVars) * sizeof(*lvaTable));
       for (unsigned i = startVars; i < lvaCount; i++)
       {
          new (&lvaTable[i], jitstd::placement_t()) LclVarDsc(this); // call the constructor.
       }

       lvaCount = startVars;

#ifdef DEBUG
       if  (verbose)
       {
          // printf("Inlining failed. Restore lvaCount to %d.\n", lvaCount);
       }
#endif

       return;
    }

    // Success!

#ifdef DEBUG
    if  (verbose)
    {
       // printf("After inlining lvaCount=%d.\n", lvaCount);
    }
#endif
}

/*****************************************************************************
 *
 * Performs checks to see if this tail call can be optimized as epilog+jmp.
 */
bool                Compiler::fgCanFastTailCall(GenTreeCall* callee)
{
#if FEATURE_FASTTAILCALL
    // Reached here means that return types of caller and callee are tail call compatible.
    // In case of structs that can be returned in a register, compRetNativeType is set to the actual return type.
    //
    // In an implicit tail call case callSig may not be available but it is guaranteed to be available
    // for explicit tail call cases.  The reason implicit tail case callSig may not be available is that
    // a call node might be marked as an in-line candidate and could fail to be in-lined. In which case
    // fgInline() will replace return value place holder with call node using gtCloneExpr() which is
    // currently not copying/setting callSig.
#ifdef DEBUG
    if (callee->IsTailPrefixedCall())
    {
        assert(impTailCallRetTypeCompatible(info.compRetNativeType, info.compMethodInfo->args.retTypeClass, 
                                            (var_types)callee->gtReturnType, callee->callSig->retTypeClass));
    }
#endif

    // Note on vararg methods:
    // If the caller is vararg method, we don't know the number of arguments passed by caller's caller.
    // But we can be sure that in-coming arg area of vararg caller would be sufficient to hold its 
    // fixed args. Therefore, we can allow a vararg method to fast tail call other methods as long as
    // out-going area required for callee is bounded by caller's fixed argument space.
    // 
    // Note that callee being a vararg method is not a problem since we can account the params being passed.

    // Count of caller args including implicit and hidden (i.e. thisPtr, RetBuf, GenericContext, VarargCookie)
    unsigned nCallerArgs = info.compArgsCount;

    // Count the callee args including implicit and hidden.
    // Note that GenericContext and VarargCookie are added by importer while
    // importing the call to gtCallArgs list along with explicit user args.
    unsigned nCalleeArgs = 0;        
    if (callee->gtCallObjp)  // thisPtr
    {
        nCalleeArgs++;
    }

    if (callee->HasRetBufArg())  // RetBuf
    {
        nCalleeArgs++;

        // If callee has RetBuf param, caller too must have it.
        // Otherwise go the slow route.
        if (info.compRetBuffArg == BAD_VAR_NUM)
        {
            return false;
        }
    }

    // Count user args while tracking whether any of them is a multi-byte params
    // that cannot be passed in a register. Note that we don't need to count
    // non-standard and secret params passed in registers (e.g. R10, R11) since
    // these won't contribute to out-going arg size.
    bool hasMultiByteArgs = false;
    for (GenTreePtr args = callee->gtCallArgs; (args != nullptr) && !hasMultiByteArgs; args = args->gtOp.gtOp2)
    {
        nCalleeArgs++;

        assert(args->IsList());
        GenTreePtr argx = args->gtOp.gtOp1;

        if (varTypeIsStruct(argx))
        {
            // Actual arg may be a child of a GT_COMMA. Skip over comma opers.
            while (argx->gtOper == GT_COMMA)
            {
                argx = argx->gtOp.gtOp2;
            }

            // Get the size of the struct and see if it is register passable.
            if (argx->OperGet() == GT_OBJ)
            {
#if defined(_TARGET_AMD64_) || defined(_TARGET_ARM64_)

                unsigned typeSize = 0;
                hasMultiByteArgs = !VarTypeIsMultiByteAndCanEnreg(argx->TypeGet(), argx->gtObj.gtClass, &typeSize, false);

#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING) || defined(_TARGET_ARM64_)
                // On System V/arm64 the args could be a 2 eightbyte struct that is passed in two registers.
                // Account for the second eightbyte in the nCalleeArgs.
                // https://github.com/dotnet/coreclr/issues/2666
                // TODO-CQ-Amd64-Unix/arm64:  Structs of size between 9 to 16 bytes are conservatively estimated
                //                            as two args, since they need two registers whereas nCallerArgs is
                //                            counting such an arg as one. This would mean we will not be optimizing
                //                            certain calls though technically possible.

                if (typeSize > TARGET_POINTER_SIZE)
                {
                    unsigned extraArgRegsToAdd = (typeSize / TARGET_POINTER_SIZE);
                    nCalleeArgs += extraArgRegsToAdd;
                }
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING || _TARGET_ARM64_

#else
                assert(!"Target platform ABI rules regarding passing struct type args in registers");
                unreached();
#endif //_TARGET_AMD64_ || _TARGET_ARM64_

            }
            else
            {
                hasMultiByteArgs = true;
            }
        }
    }

    // Go the slow route, if it has multi-byte params
    if (hasMultiByteArgs)
    {
        return false;
    }

    // If we reached here means that callee has only those argument types which can be passed in
    // a register and if passed on stack will occupy exactly one stack slot in out-going arg area.
    // If we are passing args on stack for callee and it has more args passed on stack than
    // caller, then fast tail call cannot be performed.
    //
    // Note that the GC'ness of on stack args need not match since the arg setup area is marked
    // as non-interruptible for fast tail calls.
    if ((nCalleeArgs > MAX_REG_ARG) && (nCallerArgs < nCalleeArgs))
    {
        return false;
    }

    return true;
#else
    return false;
#endif
}


/*****************************************************************************
 *
 *  Transform the given GT_CALL tree for tail call code generation.
 */
void                Compiler::fgMorphTailCall(GenTreeCall* call)
{
    // x86 classic codegen doesn't require any morphing
#if defined(_TARGET_X86_) && !defined(LEGACY_BACKEND)
    NYI_X86("Tail call morphing");
#elif defined(_TARGET_ARM_)
    // For the helper-assisted tail calls, we need to push all the arguments
    // into a single list, and then add a few extra at the beginning

    // Check for PInvoke call types that we don't handle in codegen yet.
    assert(!call->IsUnmanaged());
    assert(call->IsVirtual() ||
           (call->gtCallType != CT_INDIRECT) ||
           (call->gtCallCookie == NULL));

    // First move the this pointer (if any) onto the regular arg list
    GenTreePtr thisPtr = NULL;
    if (call->gtCallObjp)
    {
        GenTreePtr objp = call->gtCallObjp;
        call->gtCallObjp = NULL;

        if ((call->gtFlags & GTF_CALL_NULLCHECK) ||
            call->IsVirtualVtable())
        {
            thisPtr = gtClone(objp, true);
            var_types  vt = objp->TypeGet();
            if (thisPtr == NULL)
            {
                // Too complex, so use a temp
                unsigned lclNum = lvaGrabTemp(true DEBUGARG("tail call thisptr"));
                GenTreePtr asg  = gtNewTempAssign(lclNum, objp);
                if (!call->IsVirtualVtable())
                {
                    // Add an indirection to get the nullcheck
                    GenTreePtr tmp = gtNewLclvNode(lclNum, vt);
                    GenTreePtr ind = gtNewOperNode(GT_IND, TYP_INT, tmp);
                    asg  = gtNewOperNode(GT_COMMA, TYP_VOID, asg, ind);
                }
                objp = gtNewOperNode(GT_COMMA, vt, asg, gtNewLclvNode(lclNum, vt));
                thisPtr = gtNewLclvNode(lclNum, vt);
            }
            else if (!call->IsVirtualVtable())
            {
                GenTreePtr ind = gtNewOperNode(GT_IND, TYP_INT, thisPtr);
                objp = gtNewOperNode(GT_COMMA, vt, ind, objp);
                thisPtr = gtClone(thisPtr, true);
            }

            call->gtFlags &= ~GTF_CALL_NULLCHECK;
        }

        GenTreeArgList** pList = &call->gtCallArgs;
#if RETBUFARG_PRECEDES_THIS
        if (call->HasRetBufArg()) {
           pList = &(*pList)->Rest();
        }
#endif // RETBUFARG_PRECEDES_THIS
        *pList = gtNewListNode(objp, *pList);
    }

    // Add the extra VSD parameter if needed
    CorInfoHelperTailCallSpecialHandling flags = CorInfoHelperTailCallSpecialHandling(0);
    if (call->IsVirtualStub())
    {
        flags = CORINFO_TAILCALL_STUB_DISPATCH_ARG;

        GenTreePtr arg;
        if (call->gtCallType == CT_INDIRECT) {
            arg = gtClone(call->gtCallAddr, true);
            noway_assert(arg != NULL);
        }
        else {
            noway_assert(call->gtCallMoreFlags & GTF_CALL_M_VIRTSTUB_REL_INDIRECT);
            ssize_t addr = ssize_t(call->gtStubCallStubAddr);
            arg = gtNewIconHandleNode(addr, GTF_ICON_FTN_ADDR);

            // Change the call type, so we can add the extra indirection here, rather than in codegen
            call->gtCallAddr = gtNewIconHandleNode(addr, GTF_ICON_FTN_ADDR);
            call->gtStubCallStubAddr = NULL;
            call->gtCallType = CT_INDIRECT;
        }
        // Add the extra indirection to generate the real target
        call->gtCallAddr = gtNewOperNode(GT_IND, TYP_I_IMPL, call->gtCallAddr);
        call->gtFlags |= GTF_EXCEPT;

        // And push the stub address onto the list of arguments
        call->gtCallArgs = gtNewListNode(arg, call->gtCallArgs);
    }
    else if (call->IsVirtualVtable())
    {
        // TODO-ARM-NYI: for x64 handle CORINFO_TAILCALL_THIS_IN_SECRET_REGISTER

        noway_assert(thisPtr != NULL);

        GenTreePtr add  = gtNewOperNode(GT_ADD, TYP_I_IMPL, thisPtr, gtNewIconNode(VPTR_OFFS, TYP_I_IMPL));
        GenTreePtr vtbl = gtNewOperNode(GT_IND, TYP_I_IMPL, add);
        vtbl->gtFlags |= GTF_EXCEPT;

        unsigned   vtabOffsOfIndirection;
        unsigned   vtabOffsAfterIndirection;
        info.compCompHnd->getMethodVTableOffset(call->gtCallMethHnd, &vtabOffsOfIndirection, &vtabOffsAfterIndirection);

        /* Get the appropriate vtable chunk */

        add  = gtNewOperNode(GT_ADD, TYP_I_IMPL, vtbl, gtNewIconNode(vtabOffsOfIndirection, TYP_I_IMPL));
        vtbl = gtNewOperNode(GT_IND, TYP_I_IMPL, add);

        /* Now the appropriate vtable slot */

        add  = gtNewOperNode(GT_ADD, TYP_I_IMPL, vtbl, gtNewIconNode(vtabOffsAfterIndirection, TYP_I_IMPL));
        vtbl = gtNewOperNode(GT_IND, TYP_I_IMPL, add);

        // Switch this to a plain indirect call
        call->gtFlags &= ~GTF_CALL_VIRT_KIND_MASK;
        assert(!call->IsVirtual());
        call->gtCallType = CT_INDIRECT;

        call->gtCallAddr = vtbl;
        call->gtCallCookie = NULL;
        call->gtFlags |= GTF_EXCEPT;
    }

    // Now inject a placeholder for the real call target that codegen
    // will generate
    GenTreePtr arg = new (this, GT_NOP) GenTreeOp(GT_NOP, TYP_I_IMPL);
    codeGen->genMarkTreeInReg(arg, REG_TAILCALL_ADDR);
    call->gtCallArgs = gtNewListNode(arg, call->gtCallArgs);

    // Lastly inject the pointer for the copy routine
    noway_assert(call->callSig != NULL);
    void * pfnCopyArgs = info.compCompHnd->getTailCallCopyArgsThunk(call->callSig, flags);
    arg = gtNewIconHandleNode(ssize_t(pfnCopyArgs), GTF_ICON_FTN_ADDR);
    call->gtCallArgs = gtNewListNode(arg, call->gtCallArgs);

    // It is now a varargs tail call
    call->gtCallMoreFlags = GTF_CALL_M_VARARGS | GTF_CALL_M_TAILCALL;
    call->gtFlags &= ~GTF_CALL_POP_ARGS;

#elif defined(_TARGET_AMD64_)
    // For the helper-assisted tail calls, we need to push all the arguments
    // into a single list, and then add a few extra at the beginning.
    //
    // TailCallHelper(void *copyRoutine, void *callTarget, ....) - i.e We need to add
    // copyRoutine and callTarget extra params at the beginning.  But callTarget is
    // determined by Lower phase.  Therefore, we add a place holder arg for callTarget
    // here which will be later replaced with callTarget in tail call lowering.

    // Check for PInvoke call types that we don't handle in codegen yet.
    assert(!call->IsUnmanaged());
    assert(call->IsVirtual() ||
           (call->gtCallType != CT_INDIRECT) ||
           (call->gtCallCookie == NULL));
    
    // Don't support tail calling helper methods
    assert(call->gtCallType != CT_HELPER);

    // We come this route only for tail prefixed calls that cannot be dispatched as
    // fast tail calls
    assert(!call->IsImplicitTailCall());
    assert(!fgCanFastTailCall(call));

     // First move the this pointer (if any) onto the regular arg list    
    if (call->gtCallObjp)
    {
        GenTreePtr thisPtr = nullptr;
        GenTreePtr objp = call->gtCallObjp;
        call->gtCallObjp = nullptr;

        if (call->NeedsNullCheck())
        {            
            // clone "this" if "this" has no side effects.
            if (!(objp->gtFlags & GTF_SIDE_EFFECT))
            {                
                thisPtr = gtClone(objp, true);
            }
            
            var_types vt = objp->TypeGet();
            if (thisPtr == nullptr)
            {
                // create a temp if either "this" has side effects or "this" is too complex to clone.
                
                // tmp = "this"            
                unsigned lclNum = lvaGrabTemp(true DEBUGARG("tail call thisptr"));
                GenTreePtr asg  = gtNewTempAssign(lclNum, objp);
                
                // COMMA(tmp = "this", deref(tmp))
                GenTreePtr tmp = gtNewLclvNode(lclNum, vt);
                GenTreePtr ind = gtNewOperNode(GT_IND, TYP_INT, tmp);
                asg  = gtNewOperNode(GT_COMMA, TYP_VOID, asg, ind);

                // COMMA(COMMA(tmp = "this", deref(tmp)), tmp) 
                thisPtr = gtNewOperNode(GT_COMMA, vt, asg, gtNewLclvNode(lclNum, vt));
            } 
            else
            {
                // thisPtr = COMMA(deref("this"), "this")
                GenTreePtr ind = gtNewOperNode(GT_IND, TYP_INT, thisPtr);
                thisPtr = gtNewOperNode(GT_COMMA, vt, ind, gtClone(objp, true));
            }

            call->gtFlags &= ~GTF_CALL_NULLCHECK;
        }
        else
        {
            thisPtr = objp;
        }

        GenTreeArgList** pList = &call->gtCallArgs;
#if RETBUFARG_PRECEDES_THIS
        if (call->HasRetBufArg()) {
           pList = &(*pList)->Rest();
        }
#endif // RETBUFARG_PRECEDES_THIS

        // During rationalization tmp="this" and null check will
        // materialize as embedded stmts in right execution order.
        assert(thisPtr != nullptr);
        *pList = gtNewListNode(thisPtr, *pList);
    }

    // Add the extra VSD parameter to arg list in case of VSD calls.
    // Tail call arg copying thunk will move this extra VSD parameter
    // to R11 before tail calling VSD stub. See CreateTailCallCopyArgsThunk()
    // in Stublinkerx86.cpp for more details.
    CorInfoHelperTailCallSpecialHandling flags = CorInfoHelperTailCallSpecialHandling(0);
    if (call->IsVirtualStub())
    {
        GenTreePtr stubAddrArg;

        flags = CORINFO_TAILCALL_STUB_DISPATCH_ARG;

        if (call->gtCallType == CT_INDIRECT)
        {
            stubAddrArg = gtClone(call->gtCallAddr, true);
            noway_assert(stubAddrArg != nullptr);
        }
        else
        {
            noway_assert((call->gtCallMoreFlags & GTF_CALL_M_VIRTSTUB_REL_INDIRECT) != 0);

            ssize_t addr = ssize_t(call->gtStubCallStubAddr);
            stubAddrArg = gtNewIconHandleNode(addr, GTF_ICON_FTN_ADDR);
        }

        // Push the stub address onto the list of arguments
        call->gtCallArgs = gtNewListNode(stubAddrArg, call->gtCallArgs);
    }

    // Now inject a placeholder for the real call target that Lower phase will generate.
    GenTreePtr arg = gtNewIconNode(0, TYP_I_IMPL);
    call->gtCallArgs = gtNewListNode(arg, call->gtCallArgs);

    // Inject the pointer for the copy routine to be used for struct copying
    noway_assert(call->callSig != nullptr);
    void * pfnCopyArgs = info.compCompHnd->getTailCallCopyArgsThunk(call->callSig, flags);
    arg = gtNewIconHandleNode(ssize_t(pfnCopyArgs), GTF_ICON_FTN_ADDR);
    call->gtCallArgs = gtNewListNode(arg, call->gtCallArgs);

    // It is now a varargs tail call dispatched via helper.
    call->gtCallMoreFlags |= GTF_CALL_M_VARARGS | GTF_CALL_M_TAILCALL | GTF_CALL_M_TAILCALL_VIA_HELPER;
    call->gtFlags &= ~GTF_CALL_POP_ARGS;

#endif  //_TARGET_AMD64_

}

//------------------------------------------------------------------------------
// fgMorphRecursiveFastTailCallIntoLoop : Transform a recursive fast tail call into a loop.
//
//
// Arguments:
//    block  - basic block ending with a recursive fast tail call
//    recursiveTailCall - recursive tail call to transform
//
// Notes:
//    The legality of the transformation is ensured by the checks in endsWithTailCallConvertibleToLoop.

void Compiler::fgMorphRecursiveFastTailCallIntoLoop(BasicBlock* block, GenTreeCall* recursiveTailCall)
{
    assert(recursiveTailCall->IsTailCallConvertibleToLoop());
    GenTreePtr last = fgGetLastTopLevelStmt(block);
    assert(recursiveTailCall == last->gtStmt.gtStmtExpr);

    // Transform recursive tail call into a loop.

    GenTreePtr earlyArgInsertionPoint = last;
    IL_OFFSETX callILOffset = last->gtStmt.gtStmtILoffsx;

    // Hoist arg setup statement for the 'this' argument.
    GenTreePtr thisArg = recursiveTailCall->gtCallObjp;
    if (thisArg && !thisArg->IsNothingNode() && !thisArg->IsArgPlaceHolderNode())
    {
        GenTreePtr thisArgStmt = gtNewStmt(thisArg, callILOffset);
        fgInsertStmtBefore(block, earlyArgInsertionPoint, thisArgStmt);

    }

    // All arguments whose trees may involve caller parameter local variables need to be assigned to temps first;
    // then the temps need to be assigned to the method parameters. This is done so that the caller
    // parameters are not re-assigned before call arguments depending on them  are evaluated.
    // tmpAssignmentInsertionPoint and paramAssignmentInsertionPoint keep track of
    // where the next temp or parameter assignment should be inserted.

    // In the example below the first call argument (arg1 - 1) needs to be assigned to a temp first
    // while the second call argument (const 1) doesn't.
    // Basic block before tail recursion elimination:
    //  ***** BB04, stmt 1 (top level)
    //  [000037] ------------             *  stmtExpr  void  (top level) (IL 0x00A...0x013)
    //  [000033] --C - G------ - \--*  call      void   RecursiveMethod
    //  [000030] ------------ | / --*  const     int - 1
    //  [000031] ------------arg0 in rcx + --*  +int
    //  [000029] ------------ | \--*  lclVar    int    V00 arg1
    //  [000032] ------------arg1 in rdx    \--*  const     int    1
    //
    //
    //  Basic block after tail recursion elimination :
    //  ***** BB04, stmt 1 (top level)
    //  [000051] ------------             *  stmtExpr  void  (top level) (IL 0x00A... ? ? ? )
    //  [000030] ------------ | / --*  const     int - 1
    //  [000031] ------------ | / --*  +int
    //  [000029] ------------ | | \--*  lclVar    int    V00 arg1
    //  [000050] - A----------             \--* = int
    //  [000049] D------N----                \--*  lclVar    int    V02 tmp0
    //
    //  ***** BB04, stmt 2 (top level)
    //  [000055] ------------             *  stmtExpr  void  (top level) (IL 0x00A... ? ? ? )
    //  [000052] ------------ | / --*  lclVar    int    V02 tmp0
    //  [000054] - A----------             \--* = int
    //  [000053] D------N----                \--*  lclVar    int    V00 arg0

    //  ***** BB04, stmt 3 (top level)
    //  [000058] ------------             *  stmtExpr  void  (top level) (IL 0x00A... ? ? ? )
    //  [000032] ------------ | / --*  const     int    1
    //  [000057] - A----------             \--* = int
    //  [000056] D------N----                \--*  lclVar    int    V01 arg1

    GenTreePtr tmpAssignmentInsertionPoint = last;
    GenTreePtr paramAssignmentInsertionPoint = last;

    // Process early args. They may contain both setup statements for late args and actual args.
    // Early args don't include 'this' arg. We need to account for that so that the call to gtArgEntryByArgNum
    // below has the correct second argument.
    int earlyArgIndex = (thisArg == nullptr) ? 0 : 1;
    for (GenTreeArgList* earlyArgs = recursiveTailCall->gtCallArgs;
         earlyArgs != nullptr;
         (earlyArgIndex++, earlyArgs = earlyArgs->Rest()))
    {
        GenTreePtr earlyArg = earlyArgs->Current();
        if (!earlyArg->IsNothingNode() && !earlyArg->IsArgPlaceHolderNode())
        {
            if ((earlyArg->gtFlags & GTF_LATE_ARG) != 0)
            {
                // This is a setup node so we need to hoist it.
                GenTreePtr earlyArgStmt = gtNewStmt(earlyArg, callILOffset);
                fgInsertStmtBefore(block, earlyArgInsertionPoint, earlyArgStmt);
            }
            else
            {
                // This is an actual argument that needs to be assigned to the corresponding caller parameter.
                fgArgTabEntryPtr curArgTabEntry = gtArgEntryByArgNum(recursiveTailCall, earlyArgIndex);
                GenTreePtr paramAssignStmt = fgAssignRecursiveCallArgToCallerParam(earlyArg, curArgTabEntry, block, callILOffset,
                                                                                    tmpAssignmentInsertionPoint, paramAssignmentInsertionPoint);
                if ((tmpAssignmentInsertionPoint == last) && (paramAssignStmt != nullptr))
                {
                    // All temp assignments will happen before the first param assignment.
                    tmpAssignmentInsertionPoint = paramAssignStmt;
                }
            }
        }
    }

    // Process late args.
    int lateArgIndex = 0;
    for (GenTreeArgList* lateArgs = recursiveTailCall->gtCallLateArgs;
         lateArgs != nullptr;
         (lateArgIndex++, lateArgs = lateArgs->Rest()))
    {
        // A late argument is an actual argument that needs to be assigned to the corresponding caller's parameter.
        GenTreePtr lateArg = lateArgs->Current();
        fgArgTabEntryPtr curArgTabEntry = gtArgEntryByLateArgIndex(recursiveTailCall, lateArgIndex);
        GenTreePtr paramAssignStmt = fgAssignRecursiveCallArgToCallerParam(lateArg, curArgTabEntry, block, callILOffset,
                                                                           tmpAssignmentInsertionPoint, paramAssignmentInsertionPoint);

        if ((tmpAssignmentInsertionPoint == last) && (paramAssignStmt != nullptr))
        {
            // All temp assignments will happen before the first param assignment.
            tmpAssignmentInsertionPoint = paramAssignStmt;
        }
    }

    // If the method has starg.s 0 or ldarga.s 0 a special local (lvaArg0Var) is created so that
    // compThisArg stays immutable. Normally it's assigned in fgFirstBBScratch block. Since that
    // block won't be in the loop (it's assumed to have no predecessors), we need to update the special local here.
    if (!info.compIsStatic && (lvaArg0Var != info.compThisArg))
    {
        var_types  thisType = lvaTable[info.compThisArg].TypeGet();
        GenTreePtr arg0 = gtNewLclvNode(lvaArg0Var, thisType);
        GenTreePtr arg0Assignment = gtNewAssignNode(arg0, gtNewLclvNode(info.compThisArg, thisType));
        GenTreePtr arg0AssignmentStmt = gtNewStmt(arg0Assignment, callILOffset);
        fgInsertStmtBefore(block, paramAssignmentInsertionPoint, arg0AssignmentStmt);
    }

    // Remove the call
    fgRemoveStmt(block, last);

    // Set the loop edge.
    block->bbJumpKind = BBJ_ALWAYS;
    block->bbJumpDest = fgFirstBBisScratch() ? fgFirstBB->bbNext : fgFirstBB;
    fgAddRefPred(block->bbJumpDest, block);
    block->bbFlags &= ~BBF_HAS_JMP;
}

//------------------------------------------------------------------------------
// fgAssignRecursiveCallArgToCallerParam : Assign argument to a recursive call to the corresponding caller parameter.
//
//
// Arguments:
//    arg  -  argument to assign
//    argTabEntry  -  argument table entry corresponding to arg
//    block  --- basic block the call is in
//    callILOffset  -  IL offset of the call
//    tmpAssignmentInsertionPoint  -  tree before which temp assignment should be inserted (if necessary)
//    paramAssignmentInsertionPoint  -  tree before which parameter assignment should be inserted
//
// Return Value:
//    parameter assignment statement if one was inserted; nullptr otherwise.

GenTreePtr Compiler::fgAssignRecursiveCallArgToCallerParam(GenTreePtr arg,
                                                           fgArgTabEntryPtr argTabEntry,
                                                           BasicBlock *block,
                                                           IL_OFFSETX callILOffset,
                                                           GenTreePtr tmpAssignmentInsertionPoint,
                                                           GenTreePtr paramAssignmentInsertionPoint)
{
    // Call arguments should be assigned to temps first and then the temps should be assigned to parameters because
    // some argument trees may reference parameters directly.

    GenTreePtr argInTemp = nullptr;
    unsigned originalArgNum = argTabEntry->argNum;
    bool needToAssignParameter = true;

    // TODO-CQ: enable calls with struct arguments passed in registers.
    noway_assert(!varTypeIsStruct(arg->TypeGet()));

    if ((argTabEntry->isTmp) || arg->IsCnsIntOrI() || arg->IsCnsFltOrDbl())
    {
        // The argument is already assigned to a temp or is a const.
        argInTemp = arg;
    }
    else if (arg->OperGet() == GT_LCL_VAR)
    {
        unsigned lclNum = arg->AsLclVar()->gtLclNum;
        LclVarDsc * varDsc = &lvaTable[lclNum];
        if (!varDsc->lvIsParam)
        {
            // The argument is a non-parameter local so it doesn't need to be assigned to a temp.
            argInTemp = arg;
        }
        else if (lclNum == originalArgNum)
        {
            // The argument is the same parameter local that we were about to assign so
            // we can skip the assignment.
            needToAssignParameter = false;
        }
    }

    // TODO: We don't need temp assignments if we can prove that the argument tree doesn't involve
    // any caller parameters. Some common cases are handled above but we may be able to eliminate
    // more temp assignments.

    GenTreePtr paramAssignStmt = nullptr;
    if (needToAssignParameter)
    {
        if (argInTemp == nullptr)
        {
            // The argument is not assigned to a temp. We need to create a new temp and insert an assignment.
            // TODO: we can avoid a temp assignment if we can prove that the argument tree
            // doesn't involve any caller parameters. 
            unsigned tmpNum = lvaGrabTemp(true DEBUGARG("arg temp"));
            GenTreePtr  tempSrc = arg;
            GenTreePtr  tempDest = gtNewLclvNode(tmpNum, tempSrc->gtType);
            GenTreePtr tmpAssignNode = gtNewAssignNode(tempDest, tempSrc);
            GenTreePtr tmpAssignStmt = gtNewStmt(tmpAssignNode, callILOffset);
            fgInsertStmtBefore(block, tmpAssignmentInsertionPoint, tmpAssignStmt);
            argInTemp = gtNewLclvNode(tmpNum, tempSrc->gtType);
        }

        // Now assign the temp to the parameter.
        LclVarDsc *paramDsc = lvaTable + originalArgNum;
        assert(paramDsc->lvIsParam);
        GenTreePtr  paramDest = gtNewLclvNode(originalArgNum, paramDsc->lvType);
        GenTreePtr paramAssignNode = gtNewAssignNode(paramDest, argInTemp);
        paramAssignStmt = gtNewStmt(paramAssignNode, callILOffset);

        fgInsertStmtBefore(block, paramAssignmentInsertionPoint, paramAssignStmt);
    }
    return paramAssignStmt;
}

/*****************************************************************************
 *
 *  Transform the given GT_CALL tree for code generation.
 */

GenTreePtr          Compiler::fgMorphCall(GenTreeCall* call)
{
    if (call->CanTailCall())
    {
        // It should either be an explicit (i.e. tail prefixed) or an implicit tail call
        assert(call->IsTailPrefixedCall() ^ call->IsImplicitTailCall());

        // It cannot be an inline candidate
        assert(!call->IsInlineCandidate());

        const char * szFailReason = nullptr;
        bool hasStructParam = false;
        if (call->gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC)
        {
            szFailReason = "Might turn into an intrinsic";
        }

        if (opts.compNeedSecurityCheck)
        {
            szFailReason = "Needs security check";
        }
        else if (compLocallocUsed)
        {
            szFailReason = "Localloc used";
        }
#ifdef _TARGET_AMD64_
        // Needed for Jit64 compat.  
        // In future, enabling tail calls from methods that need GS cookie check
        // would require codegen side work to emit GS cookie check before a tail
        // call.
        else if (getNeedsGSSecurityCookie())
        {
            szFailReason = "GS Security cookie check";
        }
#endif
#ifdef DEBUG
        // DDB 99324: Just disable tailcall under compGcChecks stress mode.
        else if (opts.compGcChecks)
        {
            szFailReason = "GcChecks";
        }
#endif
#if FEATURE_TAILCALL_OPT
        else
        {
            // We are still not sure whether it can be a tail call. Because, when converting
            // a call to an implicit tail call, we must check that there are no locals with
            // their address taken.  If this is the case, we have to assume that the address
            // has been leaked and the current stack frame must live until after the final
            // call.

            // Verify that none of vars has lvHasLdAddrOp or lvAddrExposed bit set. Note 
            // that lvHasLdAddrOp is much more conservative.  We cannot just base it on
            // lvAddrExposed alone since it is not guaranteed to be set on all VarDscs
            // during morph stage. The reason for also checking lvAddrExposed is that in case
            // of vararg methods user args are marked as addr exposed but not lvHasLdAddrOp.
            // The combination of lvHasLdAddrOp and lvAddrExposed though conservative allows us
            // never to be incorrect.
            //
            // TODO-Throughput: have a compiler level flag to indicate whether method has vars whose
            // address is taken. Such a flag could be set whenever lvHasLdAddrOp or LvAddrExposed
            // is set. This avoids the need for iterating through all lcl vars of the current 
            // method.  Right now throughout the code base we are not consistently using 'set' 
            // method to set lvHasLdAddrOp and lvAddrExposed flags.
            unsigned varNum;
            LclVarDsc *varDsc;
            bool hasAddrExposedVars = false;
            bool hasStructPromotedParam = false;
            bool hasPinnedVars = false;

            for (varNum = 0, varDsc = lvaTable; varNum < lvaCount; varNum++, varDsc++)
            {
                // If the method is marked as an explicit tail call we will skip the
                // following three hazard checks.
                // We still must check for any struct parameters and set 'hasStructParam'
                // so that we won't transform the recursive tail call into a loop.
                // 
                if (call->IsImplicitTailCall())
                {
                    if (varDsc->lvHasLdAddrOp || varDsc->lvAddrExposed)
                    {
                        hasAddrExposedVars = true;
                        break;
                    }
                    if (varDsc->lvPromoted && varDsc->lvIsParam)
                    {
                        hasStructPromotedParam = true;
                        break;
                    }
                    if (varDsc->lvPinned)
                    {
                        // A tail call removes the method from the stack, which means the pinning
                        // goes away for the callee.  We can't allow that.
                        hasPinnedVars = true;
                        break;
                    }
                }
                if (varTypeIsStruct(varDsc->TypeGet()) && varDsc->lvIsParam)
                {
                    hasStructParam = true;
                    // This prevents transforming a recursive tail call into a loop
                    // but doesn't prevent tail call optimization so we need to
                    // look at the rest of parameters.
                    continue;
                }
            }

            if (hasAddrExposedVars)
            {
                szFailReason = "Local address taken";
            }
            if (hasStructPromotedParam)
            {
                szFailReason = "Has Struct Promoted Param";
            }
            if (hasPinnedVars)
            {
                szFailReason = "Has Pinned Vars";
            }
        }
#endif // FEATURE_TAILCALL_OPT

        fgFixupStructReturn(call);

        var_types   callType = call->TypeGet();

        // We have to ensure to pass the incoming retValBuf as the
        // outgoing one. Using a temp will not do as this function will
        // not regain control to do the copy. 

        if (info.compRetBuffArg != BAD_VAR_NUM)
        {
            noway_assert(callType == TYP_VOID);
            GenTreePtr retValBuf = call->gtCallArgs->gtOp.gtOp1;
            if (retValBuf->gtOper != GT_LCL_VAR ||
                retValBuf->gtLclVarCommon.gtLclNum != info.compRetBuffArg)
            {
                szFailReason = "Need to copy return buffer";
            }
        }

        // If this is an opportunistic tail call and cannot be dispatched as
        // fast tail call, go the non-tail call route.  This is done for perf
        // reason.
        //
        // Avoid the cost of determining whether can be dispatched as fast tail
        // call if we already know that tail call cannot be honored for other
        // reasons.
        bool canFastTailCall = false;
        if (szFailReason == nullptr)
        {
            canFastTailCall = fgCanFastTailCall(call);
            if (!canFastTailCall)
            {
                // Implicit or opportunistic tail calls are always dispatched via fast tail call
                // mechanism and never via tail call helper for perf.
                if (call->IsImplicitTailCall())
                {
                    szFailReason = "Opportunistic tail call cannot be dispatched as epilog+jmp";
                }
#ifndef LEGACY_BACKEND
                else if (!call->IsVirtualStub() && call->HasNonStandardArgs())
                {
                    // If we are here, it means that the call is an explicitly ".tail" prefixed and cannot be
                    // dispatched as a fast tail call.

                    // Methods with non-standard args will have indirection cell or cookie param passed
                    // in callee trash register (e.g. R11). Tail call helper doesn't preserve it before
                    // tail calling the target method and hence ".tail" prefix on such calls needs to be
                    // ignored.
                    //
                    // Exception to the above rule: although Virtual Stub Dispatch (VSD) calls though require
                    // extra stub param (e.g. in R11 on Amd64), they can still be called via tail call helper. 
                    // This is done by by adding stubAddr as an additional arg before the original list of 
                    // args. For more details see fgMorphTailCall() and CreateTailCallCopyArgsThunk()
                    // in Stublinkerx86.cpp.
                    szFailReason = "Method with non-standard args passed in callee trash register cannot be tail called via helper";
                }
#ifdef _TARGET_ARM64_
                else
                {
                    // NYI - TAILCALL_RECURSIVE/TAILCALL_HELPER.
                    // So, bail out if we can't make fast tail call.
                    szFailReason = "Non-qualified fast tail call";
                }
#endif
#endif //LEGACY_BACKEND
            }
        }

        // Clear these flags before calling fgMorphCall() to avoid recursion.
        bool isTailPrefixed = call->IsTailPrefixedCall();
        call->gtCallMoreFlags &= ~GTF_CALL_M_EXPLICIT_TAILCALL;

#if FEATURE_TAILCALL_OPT
        call->gtCallMoreFlags &= ~GTF_CALL_M_IMPLICIT_TAILCALL;
#endif
        
#ifdef FEATURE_PAL
        if (!canFastTailCall && szFailReason == nullptr)
        {
            szFailReason = "Non fast tail calls disabled for PAL based systems.";
        }
#endif // FEATURE_PAL

        if (szFailReason != nullptr)
        {
#ifdef DEBUG
            if (verbose) {
                printf("\nRejecting tail call late for call ");
                printTreeID(call);
                printf(": %s\n", szFailReason);
            }
#endif

            // for non user funcs, we have no handles to report
            info.compCompHnd->reportTailCallDecision(nullptr,
                (call->gtCallType == CT_USER_FUNC) ? call->gtCallMethHnd : nullptr,
                isTailPrefixed, TAILCALL_FAIL, szFailReason);

            goto NO_TAIL_CALL;
        }

#if !FEATURE_TAILCALL_OPT_SHARED_RETURN
        // We enable shared-ret tail call optimization for recursive calls even if
        // FEATURE_TAILCALL_OPT_SHARED_RETURN is not defined.
        if (gtIsRecursiveCall(call))
#endif
        {
            // Many tailcalls will have call and ret in the same block, and thus be BBJ_RETURN,
            // but if the call falls through to a ret, and we are doing a tailcall, change it here.
            if (compCurBB->bbJumpKind != BBJ_RETURN)
                compCurBB->bbJumpKind = BBJ_RETURN;

        }

        // Set this flag before calling fgMorphCall() to prevent inlining this call.
        call->gtCallMoreFlags |= GTF_CALL_M_TAILCALL;

        bool fastTailCallToLoop = false;
#if FEATURE_TAILCALL_OPT
        // TODO-CQ: enable the transformation when the method has a struct parameter that can be passed in a register
        // or return type is a struct that can be passed in a register.
        //
        // TODO-CQ: if the method being compiled requires generic context reported in gc-info (either through
        // hidden generic context param or through keep alive thisptr), then while transforming a recursive
        // call to such a method requires that the generic context stored on stack slot be updated.  Right now,
        // fgMorphRecursiveFastTailCallIntoLoop() is not handling update of generic context while transforming
        // a recursive call into a loop.  Another option is to modify gtIsRecursiveCall() to check that the
        // generic type parameters of both caller and callee generic method are the same.
        if (opts.compTailCallLoopOpt &&
            canFastTailCall &&
            gtIsRecursiveCall(call) &&
            !lvaReportParamTypeArg() &&
            !lvaKeepAliveAndReportThis() &&
            !call->IsVirtual() &&
            !hasStructParam &&
            !varTypeIsStruct(call->TypeGet()))
        {
            call->gtCallMoreFlags |= GTF_CALL_M_TAILCALL_TO_LOOP;
            fastTailCallToLoop = true;
        }
#endif

        // Do some target-specific transformations (before we process the args, etc.)
        // This is needed only for tail prefixed calls that cannot be dispatched as
        // fast calls.
        if (!canFastTailCall)
        {
            fgMorphTailCall(call);
        }

        // Implementation note : If we optimize tailcall to do a direct jump
        // to the target function (after stomping on the return address, etc),
        // without using CORINFO_HELP_TAILCALL, we have to make certain that
        // we don't starve the hijacking logic (by stomping on the hijacked
        // return address etc).

        // At this point, we are committed to do the tailcall.
        compTailCallUsed = true;

        CorInfoTailCall tailCallResult;

        if (fastTailCallToLoop)
        {
            tailCallResult = TAILCALL_RECURSIVE;
        }
        else if (canFastTailCall)
        {
            tailCallResult = TAILCALL_OPTIMIZED;
        }
        else
        {
            tailCallResult = TAILCALL_HELPER;
        }

        // for non user funcs, we have no handles to report
        info.compCompHnd->reportTailCallDecision(nullptr,
                                                 (call->gtCallType == CT_USER_FUNC) ? call->gtCallMethHnd : nullptr,
                                                 isTailPrefixed, 
                                                 tailCallResult,
                                                 nullptr);

        // As we will actually call CORINFO_HELP_TAILCALL, set the callTyp to TYP_VOID.
        // to avoid doing any extra work for the return value.
        call->gtType = TYP_VOID;

#ifdef DEBUG
        if (verbose)
        {
            printf("\nGTF_CALL_M_TAILCALL bit set for call ");
            printTreeID(call);
            printf("\n");
            if (fastTailCallToLoop)
            {
                printf("\nGTF_CALL_M_TAILCALL_TO_LOOP bit set for call ");
                printTreeID(call);
                printf("\n");
            }
        }
#endif

        GenTreePtr stmtExpr = fgMorphStmt->gtStmt.gtStmtExpr;
        bool deleteReturn = false;
        if (info.compRetBuffArg != BAD_VAR_NUM)
        {
            // In this case we simply have a call followed by a return.
            noway_assert(fgMorphStmt->gtNext->gtStmt.gtStmtExpr->gtOper == GT_RETURN);
            deleteReturn = true;
        }
        else if ((stmtExpr->gtOper == GT_ASG) && (fgMorphStmt->gtNext != nullptr))
        {
            GenTreePtr nextStmtExpr = fgMorphStmt->gtNext->gtStmt.gtStmtExpr;
            noway_assert(nextStmtExpr->gtOper == GT_RETURN);
            // In this case we have an assignment of the result of the call, and then a return of the  result of the assignment.
            // This can occur if impSpillStackEnsure() has introduced an assignment to a temp.
            noway_assert(stmtExpr->gtGetOp1()->OperIsLocal() &&
                         nextStmtExpr->OperGet() == GT_RETURN &&
                         nextStmtExpr->gtGetOp1() != nullptr &&
                         nextStmtExpr->gtGetOp1()->OperIsLocal() &&
                         stmtExpr->gtGetOp1()->AsLclVarCommon()->gtLclNum == nextStmtExpr->gtGetOp1()->AsLclVarCommon()->gtLclNum);
            deleteReturn = true;
        }
        if (deleteReturn)
        {
            fgRemoveStmt(compCurBB, fgMorphStmt->gtNext);
        }

        // For void calls, we would have created a GT_CALL in the stmt list.
        // For non-void calls, we would have created a GT_RETURN(GT_CAST(GT_CALL)).
        // For calls returning structs, we would have a void call, followed by a void return.
        // For debuggable code, it would be an assignment of the call to a temp
        // We want to get rid of any of this extra trees, and just leave
        // the call
        
        bool tailCallFollowedByPopAndRet = false;
        GenTreePtr stmt;

#ifdef DEBUG
        noway_assert((stmtExpr->gtOper == GT_CALL && stmtExpr == call) ||   // Either a call stmt
                     (stmtExpr->gtOper == GT_RETURN && (stmtExpr->gtOp.gtOp1 == call || stmtExpr->gtOp.gtOp1->gtOp.gtOp1 == call)) || // GT_RETURN(GT_CALL(..))
                     (stmtExpr->gtOper == GT_ASG && stmtExpr->gtOp.gtOp2 == call));  // or var = call
#endif
        
#ifdef _TARGET_AMD64_
        if ((stmtExpr->gtOper == GT_CALL) && (fgMorphStmt->gtNext != nullptr))
        {
            // We have a stmt node after a tail call node. This must be a tail call occuring
            // in the following IL pattern
            //    tail.call
            //    pop
            //    ret
            // Since tail prefix is honored, we can get rid of the remaining two stmts
            // corresponding to pop and ret. Note that 'pop' may or may not result in 
            // a new statement (see impImportBlockCode() for details).
            stmt = fgMorphStmt->gtNext;
            if (stmt->gtNext != nullptr) 
            {
                // We have a pop tree. 
                // It must be side effect free.
                GenTreePtr ret = stmt->gtNext;
                noway_assert((stmt->gtStmt.gtStmtExpr->gtFlags & GTF_ALL_EFFECT) == 0);
                fgRemoveStmt(compCurBB, stmt);
                stmt = ret;
            }
            noway_assert(stmt->gtStmt.gtStmtExpr->gtOper == GT_RETURN);
            fgRemoveStmt(compCurBB, stmt);
            
            tailCallFollowedByPopAndRet = true;
        }
#else //!TARGET_AMD64_

#ifdef DEBUG
        noway_assert(fgMorphStmt->gtNext == nullptr);
#endif

#endif //!_TARGET_AMD64_

        fgMorphStmt->gtStmt.gtStmtExpr = call;

        // Tail call via helper: The VM can't use return address hijacking if we're
        // not going to return and the helper doesn't have enough info to safely poll,
        // so we poll before the tail call, if the block isn't already safe.  Since
        // tail call via helper is a slow mechanism it doen't matter whether we emit
        // GC poll.  This is done to be in parity with Jit64. Also this avoids GC info
        // size increase if all most all methods are expected to be tail calls (e.g. F#).
        //
        // Note that we can avoid emitting GC-poll if we know that the current BB is
        // dominated by a Gc-SafePoint block.  But we don't have dominator info at this
        // point.  One option is to just add a place holder node for GC-poll (e.g. GT_GCPOLL)
        // here and remove it in lowering if the block is dominated by a GC-SafePoint.  For
        // now it not clear whether optimizing slow tail calls is worth the effort.  As a 
        // low cost check, we check whether the first and current basic blocks are 
        // GC-SafePoints.
        //
        // Fast Tail call as epilog+jmp - No need to insert GC-poll. Instead, fgSetBlockOrder()
        // is going to mark the method as fully interruptible if the block containing this tail
        // call is reachable without executing any call.
        if (canFastTailCall ||   
            (fgFirstBB->bbFlags & BBF_GC_SAFE_POINT) ||
            (compCurBB->bbFlags & BBF_GC_SAFE_POINT) || 
            !fgCreateGCPoll(GCPOLL_INLINE, compCurBB))
        {
            // We didn't insert a poll block, so we need to morph the call now
            // (Normally it will get morphed when we get to the split poll block)
            GenTreePtr temp = fgMorphCall(call);
            noway_assert(temp == call);
        }

        // Tail call via helper: we just call CORINFO_HELP_TAILCALL, and it jumps to
        // the target. So we don't need an epilog - just like CORINFO_HELP_THROW.
        //
        // Fast tail call: in case of fast tail calls, we need a jmp epilog and
        // hence mark it as BBJ_RETURN with BBF_JMP flag set.
        noway_assert(compCurBB->bbJumpKind == BBJ_RETURN);

        if (canFastTailCall)
        {
            compCurBB->bbFlags |= BBF_HAS_JMP;
        }
        else
        {
            compCurBB->bbJumpKind = BBJ_THROW;
        }

        // For non-void calls, we return a place holder which will be
        // used by the parent GT_RETURN node of this call.  This should
        // not be done for tail calls occuring in the following IL pattern,
        // since this pattern is supported only in void returning methods.
        //    tail.call
        //    pop
        //    ret

        GenTree* result = call;

        if (!tailCallFollowedByPopAndRet && (callType != TYP_VOID) && info.compRetType != TYP_VOID)
        {
#ifdef _TARGET_ARM_
            // Return a dummy node, as the return is already removed.
            if (callType == TYP_STRUCT)
            {
                // This is a HFA, use float 0.
                callType = TYP_FLOAT;
            }
#elif defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
            // Return a dummy node, as the return is already removed.
            if (varTypeIsStruct(callType))
            {
                // This is a register-returned struct. Return a 0.
                // The actual return registers are hacked in lower and the register allocator.
                callType = TYP_INT;
            }
#endif
#ifdef FEATURE_SIMD
            // Return a dummy node, as the return is already removed.
            if (varTypeIsSIMD(callType))
            {
                callType = TYP_DOUBLE;
            }
#endif
            result = gtNewZeroConNode(genActualType(callType));
            result = fgMorphTree(result);
        }

        return result;
    }

NO_TAIL_CALL:

    if ((call->gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC) == 0        &&
        (call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_VIRTUAL_FUNC_PTR)
#ifdef FEATURE_READYTORUN_COMPILER
        || call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_READYTORUN_VIRTUAL_FUNC_PTR)
#endif
        ) &&
        (call == fgMorphStmt->gtStmt.gtStmtExpr))
    {
        // This is call to CORINFO_HELP_VIRTUAL_FUNC_PTR with ignored result.
        // Transform it into a null check.

        GenTreePtr thisPtr = call->gtCallArgs->gtOp.gtOp1;

        GenTreePtr nullCheck = gtNewOperNode(GT_IND, TYP_I_IMPL, thisPtr);
        nullCheck->gtFlags |= GTF_EXCEPT;

        return fgMorphTree(nullCheck);
    }

    noway_assert(call->gtOper == GT_CALL);

    //
    // Only count calls once (only in the global morph phase)
    //
    if (fgGlobalMorph)
    {
        if (call->gtCallType == CT_INDIRECT)
        {
            optCallCount++;
            optIndirectCallCount++;
        }
        else if (call->gtCallType == CT_USER_FUNC)
        {
            optCallCount++;
            if (call->IsVirtual())
                optIndirectCallCount++;
        }
    }

    // Couldn't inline - remember that this BB contains method calls

    // If this is a 'regular' call, mark the basic block as
    // having a call (for computing full interruptibility).
    //
    // Amd64 note: If this is a fast tail call then don't count it as a call
    // since we don't insert GC-polls but instead make the method fully GC
    // interruptible.
#ifdef _TARGET_AMD64_
    if (!call->IsFastTailCall())
#endif
    {
        if (call->gtCallType == CT_INDIRECT)
        {
            compCurBB->bbFlags |= BBF_GC_SAFE_POINT;
        }
        else if (call->gtCallType == CT_USER_FUNC)
        {
            if ((call->gtCallMoreFlags & GTF_CALL_M_NOGCCHECK) == 0)
                compCurBB->bbFlags |= BBF_GC_SAFE_POINT;
        }
        // otherwise we have a CT_HELPER
    }

    // Morph Type.op_Equality and Type.op_Inequality
    // We need to do this before the arguments are morphed
    if ((call->gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC))
    {
        CorInfoIntrinsics methodID = info.compCompHnd->getIntrinsicID(call->gtCallMethHnd);

        genTreeOps simpleOp = GT_CALL;
        if (methodID == CORINFO_INTRINSIC_TypeEQ)
            simpleOp = GT_EQ;
        else if (methodID == CORINFO_INTRINSIC_TypeNEQ)
            simpleOp = GT_NE;

        if (simpleOp == GT_EQ || simpleOp == GT_NE)
        {
            noway_assert(call->TypeGet() == TYP_INT);

            // Check for GetClassFromHandle(handle) and obj.GetType() both of which will only return RuntimeType objects.
            // Then if either operand is one of these two calls we can simplify op_Equality/op_Inequality to GT_NE/GT_NE:
            // One important invariance that should never change is that type equivalency is always equivalent to object
            // identity equality for runtime type objects in reflection. This is also reflected in RuntimeTypeHandle::TypeEquals.
            // If this invariance would ever be broken, we need to remove the optimization below.

            GenTreePtr op1 = call->gtCallArgs->gtOp.gtOp1;
            GenTreePtr op2 = call->gtCallArgs->gtOp.gtOp2->gtOp.gtOp1;

            if (gtCanOptimizeTypeEquality(op1) || gtCanOptimizeTypeEquality(op2))
            {
                GenTreePtr compare = gtNewOperNode(simpleOp, TYP_INT, op1, op2);

                // fgMorphSmpOp will further optimize the following patterns:
                //  1. typeof(...) == typeof(...)
                //  2. typeof(...) == obj.GetType()
                return fgMorphTree(compare);
            }
        }
    }

    // Make sure that return buffers containing GC pointers that aren't too large are pointers into the stack.
    GenTreePtr origDest = nullptr; // Will only become non-null if we do the transformation (and thus require copy-back).
    unsigned retValTmpNum = BAD_VAR_NUM;
    CORINFO_CLASS_HANDLE structHnd = nullptr;
    if (call->HasRetBufArg() &&
        call->gtCallLateArgs == nullptr)  // Don't do this if we're re-morphing (which will make late args non-null).
    {
        // We're enforcing the invariant that return buffers pointers (at least for
        // struct return types containing GC pointers) are never pointers into the heap.
        // The large majority of cases are address of local variables, which are OK.
        // Otherwise, allocate a local of the given struct type, pass its address,
        // then assign from that into the proper destination.  (We don't need to do this
        // if we're passing the caller's ret buff arg to the callee, since the caller's caller
        // will maintain the same invariant.)

        GenTreePtr dest = call->gtCallArgs->gtOp.gtOp1;
        assert(dest->OperGet() != GT_ARGPLACE); // If it was, we'd be in a remorph, which we've already excluded above.
        if (dest->gtType == TYP_BYREF
            && !(dest->OperGet() == GT_ADDR && dest->gtOp.gtOp1->OperGet() == GT_LCL_VAR))
        {
            // We'll exempt helper calls from this, assuming that the helper implementation
            // follows the old convention, and does whatever barrier is required.
            if (call->gtCallType != CT_HELPER)
            {
                structHnd = call->gtRetClsHnd;
                if (info.compCompHnd->isStructRequiringStackAllocRetBuf(structHnd)
                    && !((dest->OperGet() == GT_LCL_VAR || dest->OperGet() == GT_REG_VAR)
                         && dest->gtLclVar.gtLclNum == info.compRetBuffArg))
                {
                    origDest = dest;

                    retValTmpNum = lvaGrabTemp(true DEBUGARG("substitute local for ret buff arg"));
                    lvaSetStruct(retValTmpNum, structHnd, true);
                    dest = gtNewOperNode(GT_ADDR, TYP_BYREF, gtNewLclvNode(retValTmpNum, TYP_STRUCT));
                }
            }
        }

        call->gtCallArgs->gtOp.gtOp1 = dest;
    }

    /* Process the "normal" argument list */
    call = fgMorphArgs(call);

    // Optimize get_ManagedThreadId(get_CurrentThread)
    noway_assert(call->gtOper == GT_CALL);

    // Morph stelem.ref helper call to store a null value, into a store into an array without the helper.
    // This needs to be done after the arguments are morphed to ensure constant propagation has already taken place.
    if ((call->gtCallType == CT_HELPER) && (call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_ARRADDR_ST)))
    {       
        GenTreePtr value = gtArgEntryByArgNum(call, 2)->node;

        if (value->OperGet() == GT_CNS_INT && value->AsIntConCommon()->IconValue() == 0)
        {
            GenTreePtr arr = gtArgEntryByArgNum(call, 0)->node;
            GenTreePtr index = gtArgEntryByArgNum(call, 1)->node;

            arr = gtClone(arr, true);
            if (arr != nullptr)
            {
                index = gtClone(index, true);
                if (index != nullptr)
                {
                    value = gtClone(value);
                    noway_assert(value != nullptr);

                    GenTreePtr nullCheckedArr = impCheckForNullPointer(arr);
                    GenTreePtr arrIndexNode = gtNewIndexRef(TYP_REF, nullCheckedArr, index);
                    GenTreePtr arrStore = gtNewAssignNode(arrIndexNode, value);
                    arrStore->gtFlags |= GTF_ASG;

                    return fgMorphTree(arrStore);
                }                
            }
        }
    }

    if ((call->gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC) &&
           info.compCompHnd->getIntrinsicID(call->gtCallMethHnd) == CORINFO_INTRINSIC_GetManagedThreadId)
    {
        noway_assert(origDest == NULL);
        noway_assert(call->gtCallLateArgs->gtOp.gtOp1 != NULL);

        GenTreePtr innerCall = call->gtCallLateArgs->gtOp.gtOp1;

        if (innerCall->gtOper == GT_CALL &&
            (innerCall->gtCall.gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC) &&
            info.compCompHnd->getIntrinsicID(innerCall->gtCall.gtCallMethHnd) == CORINFO_INTRINSIC_GetCurrentManagedThread)
        {
            // substitute expression with call to helper
            GenTreePtr newCall = gtNewHelperCallNode(CORINFO_HELP_GETCURRENTMANAGEDTHREADID, TYP_INT, 0);
            JITDUMP("get_ManagedThreadId(get_CurrentThread) folding performed\n");
            return fgMorphTree(newCall);
        }
    }

    if (origDest != NULL)
    {
        GenTreePtr retValVarAddr = gtNewOperNode(GT_ADDR, TYP_BYREF, gtNewLclvNode(retValTmpNum, TYP_STRUCT));
        // If the origDest expression was an assignment to a variable, it might be to an otherwise-unused
        // var, which would allow the whole assignment to be optimized away to a NOP.  So in that case, make the
        // origDest into a comma that uses the var.  Note that the var doesn't have to be a temp for this to
        // be correct.
        if (origDest->OperGet() == GT_ASG)
        {
            if (origDest->gtOp.gtOp1->OperGet() == GT_LCL_VAR)
            {
                GenTreePtr var = origDest->gtOp.gtOp1;
                origDest = gtNewOperNode(GT_COMMA, var->TypeGet(), origDest,
                                         gtNewLclvNode(var->gtLclVar.gtLclNum, var->TypeGet()));
            }
        }
        GenTreePtr copyBlk = gtNewCpObjNode(origDest, retValVarAddr, structHnd, false);
        copyBlk = fgMorphTree(copyBlk);
        GenTree* result = gtNewOperNode(GT_COMMA, TYP_VOID, call, copyBlk);
#ifdef DEBUG
        result->gtFlags |= GTF_MORPHED;
#endif
        return result;
    }


    return call;
}

/*****************************************************************************
 *
 *  Transform the given GTK_CONST tree for code generation.
 */

GenTreePtr          Compiler::fgMorphConst(GenTreePtr tree)
{
    noway_assert(tree->OperKind() & GTK_CONST);

    /* Clear any exception flags or other unnecessary flags
     * that may have been set before folding this node to a constant */

    tree->gtFlags &= ~(GTF_ALL_EFFECT | GTF_REVERSE_OPS);

    if  (tree->OperGet() != GT_CNS_STR)
        return tree;

    // TODO-CQ: Do this for compCurBB->isRunRarely(). Doing that currently will
    // guarantee slow performance for that block. Instead cache the return value
    // of CORINFO_HELP_STRCNS and go to cache first giving reasonable perf.

    if (compCurBB->bbJumpKind == BBJ_THROW)
    {
        CorInfoHelpFunc helper = info.compCompHnd->getLazyStringLiteralHelper(tree->gtStrCon.gtScpHnd);
        if (helper != CORINFO_HELP_UNDEF)
        {
            // For un-important blocks, we want to construct the string lazily

            GenTreeArgList *args;
            if (helper == CORINFO_HELP_STRCNS_CURRENT_MODULE)
            {
                args = gtNewArgList(gtNewIconNode(RidFromToken(tree->gtStrCon.gtSconCPX), TYP_INT));
            }
            else
            {
                args = gtNewArgList(gtNewIconNode(RidFromToken(tree->gtStrCon.gtSconCPX), TYP_INT),
                    gtNewIconEmbScpHndNode(tree->gtStrCon.gtScpHnd));
            }


            tree = gtNewHelperCallNode(helper, TYP_REF, 0, args);
            return fgMorphTree(tree);
        }
    }

    assert(tree->gtStrCon.gtScpHnd == info.compScopeHnd || !IsUninitialized(tree->gtStrCon.gtScpHnd));

    LPVOID pValue;
    InfoAccessType iat = info.compCompHnd->constructStringLiteral(tree->gtStrCon.gtScpHnd,
                                                         tree->gtStrCon.gtSconCPX,
                                                         &pValue);

    tree = gtNewStringLiteralNode(iat, pValue);

    return fgMorphTree(tree);
}

/*****************************************************************************
 *
 *  Transform the given GTK_LEAF tree for code generation.
 */

GenTreePtr          Compiler::fgMorphLeaf(GenTreePtr tree)
{
    noway_assert(tree->OperKind() & GTK_LEAF);

    if (tree->gtOper == GT_LCL_VAR)
    {
        return fgMorphLocalVar(tree);
    }
#ifdef _TARGET_X86_
    else if (tree->gtOper == GT_LCL_FLD)
    {
        if (info.compIsVarArgs)
        {
            GenTreePtr newTree = fgMorphStackArgForVarArgs(tree->gtLclFld.gtLclNum, tree->gtType, tree->gtLclFld.gtLclOffs);
            if (newTree != NULL)
                return newTree;
        }
    }
#endif // _TARGET_X86_
    else if (tree->gtOper == GT_FTN_ADDR)
    {
        CORINFO_CONST_LOOKUP addrInfo;

#ifdef FEATURE_READYTORUN_COMPILER
        if (tree->gtFptrVal.gtEntryPoint.addr != nullptr)
        {
            addrInfo = tree->gtFptrVal.gtEntryPoint;
        }
        else
#endif
        {
            info.compCompHnd->getFunctionFixedEntryPoint(tree->gtFptrVal.gtFptrMethod, &addrInfo);
        }

        // Refer to gtNewIconHandleNode() as the template for constructing a constant handle
        //
        tree->SetOper(GT_CNS_INT);
        tree->gtIntConCommon.SetIconValue(ssize_t(addrInfo.handle));
        tree->gtFlags |= GTF_ICON_FTN_ADDR;

        switch (addrInfo.accessType)
        {
        case IAT_PPVALUE:
            tree           = gtNewOperNode(GT_IND, TYP_I_IMPL, tree);
            tree->gtFlags |= GTF_IND_INVARIANT;

            __fallthrough;

        case IAT_PVALUE:
            tree           = gtNewOperNode(GT_IND, TYP_I_IMPL, tree);
            break;

        case IAT_VALUE:
            tree = gtNewOperNode(GT_NOP, tree->TypeGet(), tree); // prevents constant folding
            break;

        default:
            noway_assert(!"Unknown addrInfo.accessType");
        }

        return fgMorphTree(tree);
    }

    return tree;
}


void Compiler::fgAssignSetVarDef(GenTreePtr tree)
{
    GenTreeLclVarCommon* lclVarCmnTree;
    bool isEntire = false;
    if (tree->DefinesLocal(this, &lclVarCmnTree, &isEntire))
    {
        if (isEntire)
        {
            lclVarCmnTree->gtFlags |= GTF_VAR_DEF;
        }
        else
        {
            // We consider partial definitions to be modeled as uses followed by definitions.
            // This captures the idea that precedings defs are not necessarily made redundant
            // by this definition.
            lclVarCmnTree->gtFlags |= (GTF_VAR_DEF | GTF_VAR_USEASG);
        }
    }
}

GenTreePtr Compiler::fgMorphOneAsgBlockOp(GenTreePtr tree)
{
    genTreeOps     oper = tree->gtOper;

    // Only xxBlk opcodes are possible
    noway_assert(tree->OperIsBlkOp());

    GenTreePtr  dest      = tree->gtOp.gtOp1->gtOp.gtOp1;   // Dest address
    GenTreePtr  src       = tree->gtOp.gtOp1->gtOp.gtOp2;   // Src
    GenTreePtr  blkShape  = tree->gtOp.gtOp2;               // [size/clsHnd]
    bool        volatil   = tree->AsBlkOp()->IsVolatile();
    GenTreePtr  result;
    GenTreePtr  lclVarTree;

    // The dest must be an address
    noway_assert(genActualType(dest->gtType) == TYP_I_IMPL  ||
           dest->gtType  == TYP_BYREF);

    // For COPYBLK the src must be an address
    noway_assert(!tree->OperIsCopyBlkOp() ||
                 (genActualType( src->gtType) == TYP_I_IMPL ||
                  src->gtType  == TYP_BYREF));

    // For INITBLK the src must be a TYP_INT
    noway_assert(oper != GT_INITBLK ||
           (genActualType( src->gtType) == TYP_INT));

    // The size must be an integer type
    noway_assert(varTypeIsIntegral(blkShape->gtType));

    CORINFO_CLASS_HANDLE  clsHnd;
    size_t                size;
    var_types             type    = TYP_UNDEF;

    if (blkShape->gtOper != GT_CNS_INT)
        goto GENERAL_BLKOP;

#ifdef FEATURE_SIMD
    // importer introduces cpblk nodes with src = GT_ADDR(GT_SIMD) 
    // The SIMD type in question could be Vector2f which is 8-bytes in size.
    // The below check is to make sure that we don't turn that copyblk
    // into a assignment, since rationalizer logic will transform the
    // copyblk apropriately. Otherwise, the transormation made in this 
    // routine will prevent rationalizer logic and we might end up with 
    // GT_ADDR(GT_SIMD) node post rationalization, leading to a noway assert
    // in codegen.
    if (src->OperGet() == GT_ADDR && src->gtGetOp1()->OperGet() == GT_SIMD)
        goto GENERAL_BLKOP;
#endif 

    if (!blkShape->IsIconHandle())
    {
        clsHnd = 0;
        size   = blkShape->gtIntCon.gtIconVal;

        /* A four byte BLK_COPY can be treated as an integer asignment */
        if (size == 4)
            type = TYP_INT;
#ifdef _TARGET_64BIT_
        if (size == 8)
            type = TYP_LONG;
#endif
    }
    else
    {
        clsHnd = (CORINFO_CLASS_HANDLE) blkShape->gtIntCon.gtIconVal;
        size   = roundUp(info.compCompHnd->getClassSize(clsHnd), sizeof(void*));

        // Since we round up, we are not handling the case where we have a
        // non-dword sized struct with GC pointers.
        // The EE currently does not allow this, but we may change.  Lets assert it
        // just to be safe.
        noway_assert(info.compCompHnd->getClassSize(clsHnd) == size);

        if (size == REGSIZE_BYTES)
        {
            BYTE gcPtr;
            info.compCompHnd->getClassGClayout(clsHnd, &gcPtr);
            type = getJitGCType(gcPtr);
        }
    }

    //
    //  See if we can do a simple transformation:
    //
    //          GT_ASG <TYP_size>
    //          /   \
    //      GT_IND GT_IND or CNS_INT
    //         |      |
    //       [dest] [src]
    //

    switch (size)
    {
    case 1:
        type = TYP_BYTE;
        goto ONE_SIMPLE_ASG;
    case 2:
        type = TYP_SHORT;
        goto ONE_SIMPLE_ASG;

#ifdef _TARGET_64BIT_
    case 4:
        type = TYP_INT;
        goto ONE_SIMPLE_ASG;
#endif // _TARGET_64BIT_

    case REGSIZE_BYTES:
        noway_assert(type != TYP_UNDEF);

ONE_SIMPLE_ASG:

        noway_assert(size <= REGSIZE_BYTES);

        // For INITBLK, a non constant source is not going to allow us to fiddle
        // with the bits to create a single assigment.

        if ((oper == GT_INITBLK) && (src->gtOper != GT_CNS_INT))
        {
            goto GENERAL_BLKOP;
        }

        if (impIsAddressInLocal(dest, &lclVarTree))
        {
#if LOCAL_ASSERTION_PROP
            // Kill everything about dest
            if (optLocalAssertionProp)
            {
                if (optAssertionCount > 0)
                {
                    fgKillDependentAssertions(lclVarTree->gtLclVarCommon.gtLclNum DEBUGARG(tree));
                }
            }
#endif // LOCAL_ASSERTION_PROP

            unsigned lclNum = lclVarTree->gtLclVarCommon.gtLclNum;
            // A previous incarnation of this code also required the local not to be
            // address-exposed(=taken).  That seems orthogonal to the decision of whether
            // to do field-wise assignments: being address-exposed will cause it to be
            // "dependently" promoted, so it will be in the right memory location.  One possible
            // further reason for avoiding field-wise stores is that the struct might have alignment-induced
            // holes, whose contents could be meaningful in unsafe code.  If we decide that's a valid
            // concern, then we could compromise, and say that address-exposed + fields do not completely cover the memory
            // of the struct prevent field-wise assignments.  Same situation exists for the "src" decision.
            if (varTypeIsStruct(lclVarTree) &&
                (lvaTable[lclNum].lvPromoted || lclVarIsSIMDType(lclNum)))
            {

                // Let fgMorphInitBlock handle it.  (Since we'll need to do field-var-wise assignments.)
                goto GENERAL_BLKOP;
            }
            else
            if (!varTypeIsFloating(lclVarTree->TypeGet())           &&
                size == genTypeSize(var_types(lvaTable[lclNum].lvType)))
            {
                // Use the dest local var directly.
                dest = lclVarTree;
                type = lvaTable[lclNum].lvType;  // Make the type used in the GT_IND node match

                // If the block operation had been a write to a local var of a small int type,
                // of the exact size of the small int type, and the var is NormalizeOnStore,
                // we would have labeled it GTF_VAR_USEASG, because the block operation wouldn't
                // have done that normalization.  If we're now making it into an assignment,
                // the NormalizeOnStore will work, and it can be a full def.
                if (lvaTable[lclNum].lvNormalizeOnStore())
                {
                    dest->gtFlags &= (~GTF_VAR_USEASG);
                }

                goto _DoneDest;
            }
            else
            {
                // Could be a non-promoted struct, or a floating point type local, or
                // an int subject to a partial write.  Don't enregister.
                lvaSetVarDoNotEnregister(lclNum DEBUGARG(DNER_LocalField));
                // Fall through to indirect the dest node.
            }
            // Mark the local var tree as a definition point of the local.
            lclVarTree->gtFlags |= GTF_VAR_DEF;
            if (size < lvaTable[lclNum].lvExactSize) // If it's not a full-width assignment....
                lclVarTree->gtFlags |= GTF_VAR_USEASG;
        }

        // Check to ensure we are not creating a reducible *(& ... )
        if (dest->gtOper == GT_ADDR)
        {
            GenTreePtr addrOp = dest->gtOp.gtOp1;
            // Ignore reinterpret casts between int/gc
            if ((addrOp->TypeGet() == type) ||
                (varTypeIsIntegralOrI(addrOp) && (genTypeSize(addrOp->TypeGet()) == size)))
            {
                dest = addrOp;
                type = addrOp->TypeGet();
                goto _DoneDest;
            }
        }

        /* Indirect the dest node */

        dest = gtNewOperNode(GT_IND, type, dest);

        /* As long as we don't have more information about the destination we
           have to assume it could live anywhere (not just in the GC heap). Mark
           the GT_IND node so that we use the correct write barrier helper in case
           the field is a GC ref.
        */

        dest->gtFlags |= (GTF_EXCEPT | GTF_GLOB_REF | GTF_IND_TGTANYWHERE);

_DoneDest:;

        if (volatil)
            dest->gtFlags |= GTF_DONT_CSE;

        if (tree->OperIsCopyBlkOp())
        {
            if (impIsAddressInLocal(src, &lclVarTree))
            {
                unsigned lclNum = lclVarTree->gtLclVarCommon.gtLclNum;
                if (varTypeIsStruct(lclVarTree) &&
                    (lvaTable[lclNum].lvPromoted || lclVarIsSIMDType(lclNum)))
                {
                    // Let fgMorphCopyBlock handle it.
                    goto GENERAL_BLKOP;
                }
                else
                if (!varTypeIsFloating(lclVarTree->TypeGet())           &&
                    size == genTypeSize(genActualType(lclVarTree->TypeGet())))
                {
                    /* Use the src local var directly */
                    src = lclVarTree;
                    goto _DoneSrc;
                }
                else
                {
#ifndef LEGACY_BACKEND

                    // The source argument of the copyblk can potentially 
                    // be accessed only through indir(addr(lclVar))
                    // or indir(lclVarAddr) in rational form and liveness 
                    // won't account for these uses. That said,
                    // we have to mark this local as address exposed so
                    // we don't delete it as a dead store later on.
                    unsigned lclVarNum = lclVarTree->gtLclVarCommon.gtLclNum;
                    lvaTable[lclVarNum].lvAddrExposed = true;
                    lvaSetVarDoNotEnregister(lclVarNum DEBUGARG(DNER_AddrExposed));

#else // LEGACY_BACKEND
                    lvaSetVarDoNotEnregister(lclVarTree->gtLclVarCommon.gtLclNum DEBUGARG(DNER_LocalField));
#endif // LEGACY_BACKEND

                    // Fall through to indirect the src node.
                }
            }

            /* Indirect the src node */

            src  = gtNewOperNode(GT_IND, type, src);
            src->gtFlags     |= (GTF_EXCEPT | GTF_GLOB_REF | GTF_IND_TGTANYWHERE);

_DoneSrc:;

            if (volatil)
                src->gtFlags |= GTF_DONT_CSE;
        }
        else // (oper == GT_INITBLK)
        {
            if (size > 1)
            {
                size_t cns = src->gtIntCon.gtIconVal;
                cns  = cns & 0xFF;
                cns |= cns << 8;
                if (size >= 4)
                {
                    cns |= cns << 16;
#ifdef _TARGET_64BIT_
                    if (size == 8)
                    {
                        cns |= cns << 32;
                    }
#endif // _TARGET_64BIT_

                    src->gtType = type;   // Make the type used in the GT_IND node match for TYP_REF

                    // if we are using an GT_INITBLK on a GC type the value being assigned has to be zero (null)
                    assert(!varTypeIsGC(type) || (cns == 0));
                }

                src->gtIntCon.gtIconVal = cns;
            }
        }

        /* Create the assignment node */

        result = gtNewAssignNode(dest, src);
        result->gtType = type;

        return result;
    }

GENERAL_BLKOP:

    return nullptr;
}

//------------------------------------------------------------------------
// fgMorphInitBlock: Perform the Morphing of a GT_INITBLK node
//
// Arguments:
//    tree - a tree node with a gtOper of GT_INITBLK
//           the child nodes for tree have already been Morphed
//
// Return Value:
//    We can return the orginal GT_INITBLK unmodified (least desirable, but always correct)
//    We can return a single assignment, when fgMorphOneAsgBlockOp transforms it (most desirable)
//    If we have performed struct promotion of the Dest() then we will try to
//    perform a field by field assignment for each of the promoted struct fields
//
// Notes:
//    If we leave it as a GT_INITBLK we will call lvaSetVarDoNotEnregister() with a reason of DNER_BlockOp
//    if the Dest() is a a struct that has a "CustomLayout" and "ConstainsHoles" then we 
//    can not use a field by field assignment and must the orginal GT_INITBLK unmodified.

GenTreePtr          Compiler::fgMorphInitBlock(GenTreePtr tree)
{
    noway_assert(tree->gtOper == GT_INITBLK);

    JITDUMP("\nfgMorphInitBlock:");

    GenTreePtr oneAsgTree = fgMorphOneAsgBlockOp(tree);
    if (oneAsgTree)
    {
        JITDUMP(" using oneAsgTree.\n");
        tree = oneAsgTree;
    }
    else
    {
        GenTreeInitBlk* initBlkOp = tree->AsInitBlk();

        GenTreePtr    destAddr  = initBlkOp->Dest();
        GenTreePtr    initVal   = initBlkOp->InitVal();
        GenTreePtr    blockSize = initBlkOp->Size();

        // The dest must be an address
        noway_assert(genActualType(destAddr->gtType) == TYP_I_IMPL  ||
               destAddr->gtType  == TYP_BYREF);

        // The size must be an integer type
        assert(varTypeIsIntegral(blockSize->gtType));

        unsigned      blockWidth        = 0;
        bool          blockWidthIsConst = false;

        if (blockSize->IsCnsIntOrI())
        {
            blockWidthIsConst = true;
            blockWidth = unsigned(blockSize->gtIntConCommon.IconValue());
        }

        GenTreeLclVarCommon* lclVarTree = nullptr;

        FieldSeqNode* destFldSeq    = nullptr;
        unsigned      destLclNum    = BAD_VAR_NUM;
        LclVarDsc *   destLclVar    = nullptr;
        bool          destDoFldAsg  = false;

        if (destAddr->IsLocalAddrExpr(this, &lclVarTree, &destFldSeq))
        {
            destLclNum = lclVarTree->gtLclNum;
            destLclVar = &lvaTable[destLclNum];

#if LOCAL_ASSERTION_PROP
            // Kill everything about destLclNum (and its field locals)
            if (optLocalAssertionProp)
            {
                if (optAssertionCount > 0)
                {
                    fgKillDependentAssertions(destLclNum DEBUGARG(tree));
                }
            }
#endif // LOCAL_ASSERTION_PROP

            if (destLclVar->lvPromoted && blockWidthIsConst)
            {
                noway_assert(varTypeIsStruct(destLclVar));
                noway_assert(!opts.MinOpts());
                if (destLclVar->lvAddrExposed & destLclVar->lvContainsHoles)
                {
                     JITDUMP(" dest is address exposed");
                }
                else
                {
                    if (blockWidth == destLclVar->lvExactSize)
                    {
                        JITDUMP(" (destDoFldAsg=true)");
                        // We may decide later that a copyblk is required when this struct has holes
                        destDoFldAsg = true;
                    }
                    else 
                    {
                        JITDUMP(" with mismatched size");
                    }
                }
            }
        }

        // Can we use field by field assignment for the dest?
        if (destDoFldAsg && destLclVar->lvCustomLayout && destLclVar->lvContainsHoles)
        {
            JITDUMP(" dest contains holes");
            destDoFldAsg = false;
        }

        JITDUMP(destDoFldAsg ? " using field by field initialization.\n"
                             : " this requires an InitBlock.\n");

        if (!destDoFldAsg && (destLclVar != nullptr))
        {
            // If destLclVar is not a reg-sized non-field-addressed struct, set it as DoNotEnregister.
            if (!destLclVar->lvRegStruct)
            {
                // Mark it as DoNotEnregister.
                lvaSetVarDoNotEnregister(destLclNum DEBUGARG(DNER_BlockOp));
            }
        }

        // Mark the dest struct as DoNotEnreg 
        // when they are LclVar structs and we are using a CopyBlock 
        // or the struct is not promoted 
        //
        if (!destDoFldAsg)
        {
#if CPU_USES_BLOCK_MOVE
            compBlkOpUsed = true;
#endif
            goto _Done;
        }

        // The initVal must be a constant of TYP_INT
        noway_assert(initVal->OperGet() == GT_CNS_INT);
        noway_assert(genActualType(initVal->gtType) == TYP_INT);

        // The dest must be of a struct type.
        noway_assert(varTypeIsStruct(destLclVar));

        //
        // Now, convert InitBlock to individual assignments
        //

        tree = nullptr;

        GenTreePtr asg;
        GenTreePtr dest;
        GenTreePtr srcCopy;
        unsigned   fieldLclNum;
        unsigned   fieldCnt = destLclVar->lvFieldCnt;

        for (unsigned i=0; i<fieldCnt; ++i)
        {
            fieldLclNum = destLclVar->lvFieldLclStart + i;
            dest = gtNewLclvNode(fieldLclNum, lvaTable[fieldLclNum].TypeGet());

            noway_assert(destAddr->gtOp.gtOp1->gtOper == GT_LCL_VAR);
            // If it had been labeled a "USEASG", assignments to the the individual promoted fields are not.
            dest->gtFlags |= destAddr->gtOp.gtOp1->gtFlags & ~(GTF_NODE_MASK | GTF_VAR_USEASG);

            srcCopy = gtCloneExpr(initVal);
            noway_assert(srcCopy != nullptr);

            // need type of oper to be same as tree
            if (dest->gtType == TYP_LONG)
            {
                srcCopy->ChangeOperConst(GT_CNS_NATIVELONG);
                // copy and extend the value
                srcCopy->gtIntConCommon.SetLngValue(initVal->gtIntConCommon.IconValue());
                /* Change the types of srcCopy to TYP_LONG */
                srcCopy->gtType = TYP_LONG;
            }
            else if (varTypeIsFloating(dest->gtType))
            {
                srcCopy->ChangeOperConst(GT_CNS_DBL);
                // setup the bit pattern
                memset(&srcCopy->gtDblCon.gtDconVal, (int)initVal->gtIntCon.gtIconVal, sizeof(srcCopy->gtDblCon.gtDconVal));
                /* Change the types of srcCopy to TYP_DOUBLE */
                srcCopy->gtType = TYP_DOUBLE;
            }
            else
            {
                noway_assert(srcCopy->gtOper == GT_CNS_INT);
                noway_assert(srcCopy->TypeGet() == TYP_INT);
                // setup the bit pattern
                memset(&srcCopy->gtIntCon.gtIconVal, (int)initVal->gtIntCon.gtIconVal, sizeof(srcCopy->gtIntCon.gtIconVal));
            }

            srcCopy->gtType = dest->TypeGet();

            asg = gtNewAssignNode(dest, srcCopy);

#if LOCAL_ASSERTION_PROP
            if (optLocalAssertionProp)
            {
                optAssertionGen(asg);
            }
#endif // LOCAL_ASSERTION_PROP

            if (tree)
            {
                tree = gtNewOperNode(GT_COMMA,
                                     TYP_VOID,
                                     tree,
                                     asg);
            }
            else
            {
                tree = asg;
            }
        }
    }

#ifdef DEBUG
    tree->gtFlags |= GTF_MORPHED;

    if (verbose)
    {
        printf("fgMorphInitBlock (after):\n");
        gtDispTree(tree);
    }
#endif

_Done:
    return tree;
}

//------------------------------------------------------------------------
// fgMorphCopyBlock: Perform the Morphing of a GT_COPYBLK and GT_COPYOBJ nodes
//
// Arguments:
//    tree - a tree node with a gtOper of GT_COPYBLK or GT_COPYOBJ
//           the child nodes for tree have already been Morphed
//
// Return Value:
//    We can return the orginal GT_COPYBLK or GT_COPYOBJ unmodified (least desirable, but always correct)
//    We can return a single assignment, when fgMorphOneAsgBlockOp transforms it (most desirable)
//    If we have performed struct promotion of the Source() or the Dest() then we will try to
//    perform a field by field assignment for each of the promoted struct fields
//
// Notes:
//    If we leave it as a GT_COPYBLK or GT_COPYOBJ we will call lvaSetVarDoNotEnregister() on both Source() and Dest()
//    When performing a field by field assignment we can have one of Source() or Dest treated as a blob of bytes
//    and in such cases we will call lvaSetVarDoNotEnregister() on the one treated as a blob of bytes.
//    if the Source() or Dest() is a a struct that has a "CustomLayout" and "ConstainsHoles" then we 
//    can not use a field by field assignment and must the orginal GT_COPYBLK unmodified.

GenTreePtr          Compiler::fgMorphCopyBlock(GenTreePtr tree)
{
    noway_assert(tree->OperIsCopyBlkOp());

    JITDUMP("\nfgMorphCopyBlock:");

    bool isLateArg = (tree->gtFlags & GTF_LATE_ARG) != 0;

    GenTreePtr oneAsgTree = fgMorphOneAsgBlockOp(tree);

    if (oneAsgTree)
    {
        JITDUMP(" using oneAsgTree.\n");
        tree = oneAsgTree;
    }
    else
    {
        GenTreePtr    destAddr; 
        GenTreePtr    srcAddr;
        GenTreePtr    blockSize;
        bool          isCopyObj;

        if (tree->OperGet() == GT_COPYBLK)
        {
            GenTreeCpBlk* copyBlkOp = tree->AsCpBlk();

            isCopyObj = false;
            destAddr  = copyBlkOp->Dest();
            srcAddr   = copyBlkOp->Source();
            blockSize = copyBlkOp->Size();
        }
        else
        {
            GenTreeCpObj* copyObjOp = tree->AsCpObj();

            isCopyObj = true;
            destAddr  = copyObjOp->Dest();
            srcAddr   = copyObjOp->Source();
            blockSize = copyObjOp->ClsTok();
        }

        noway_assert(destAddr->TypeGet() == TYP_BYREF || destAddr->TypeGet() == TYP_I_IMPL);
        noway_assert(srcAddr->TypeGet()  == TYP_BYREF || srcAddr->TypeGet()  == TYP_I_IMPL);

        unsigned    blockWidth        = 0;
        bool        blockWidthIsConst = false;

        if (blockSize->IsCnsIntOrI())
        {
            blockWidthIsConst = true;
            if (blockSize->IsIconHandle(GTF_ICON_CLASS_HDL))
            {
                CORINFO_CLASS_HANDLE clsHnd = (CORINFO_CLASS_HANDLE) blockSize->gtIntConCommon.IconValue();
                blockWidth = info.compCompHnd->getClassSize(clsHnd);
            }
            else
            {
                blockWidth = unsigned(blockSize->gtIntConCommon.IconValue());
            }
        }
  
        GenTreeLclVarCommon* lclVarTree = nullptr;

        FieldSeqNode*  destFldSeq    = nullptr;
        unsigned       destLclNum    = BAD_VAR_NUM;
        LclVarDsc*     destLclVar    = nullptr;
        bool           destDoFldAsg  = false;
        bool           destOnStack   = false;

        if (destAddr->IsLocalAddrExpr(this, &lclVarTree, &destFldSeq))
        {
            destOnStack = true;
            destLclNum = lclVarTree->gtLclNum;
            destLclVar = &lvaTable[destLclNum];

#if LOCAL_ASSERTION_PROP
            // Kill everything about destLclNum (and its field locals)
            if (optLocalAssertionProp)
            {
                if (optAssertionCount > 0)
                {
                    fgKillDependentAssertions(destLclNum DEBUGARG(tree));
                }
            }
#endif // LOCAL_ASSERTION_PROP

            if (destLclVar->lvPromoted && blockWidthIsConst)
            {
                noway_assert(varTypeIsStruct(destLclVar));
                noway_assert(!opts.MinOpts());

                if (blockWidth == destLclVar->lvExactSize)
                {
                    JITDUMP(" (destDoFldAsg=true)");
                    // We may decide later that a copyblk is required when this struct has holes
                    destDoFldAsg = true;
                }
                else 
                {
                    JITDUMP(" with mismatched dest size");
                }
            }
        }

        FieldSeqNode*  srcFldSeq    = nullptr;
        unsigned       srcLclNum    = BAD_VAR_NUM;
        LclVarDsc*     srcLclVar    = nullptr;
        bool           srcDoFldAsg  = false;

        if (srcAddr->IsLocalAddrExpr(this, &lclVarTree, &srcFldSeq))
        {
            srcLclNum = lclVarTree->gtLclNum;
            srcLclVar = &lvaTable[srcLclNum];

            if (srcLclVar->lvPromoted && blockWidthIsConst)
            {
                noway_assert(varTypeIsStruct(srcLclVar));
                noway_assert(!opts.MinOpts());

                if (blockWidth == srcLclVar->lvExactSize)
                {
                    JITDUMP(" (srcDoFldAsg=true)");
                    // We may decide later that a copyblk is required when this struct has holes
                    srcDoFldAsg = true;
                }
                else 
                {
                    JITDUMP(" with mismatched src size");
                }
            }
        }

        // Check to see if we are required to do a copy block because the struct contains holes
        // and either the src or dest is externally visible
        //
        bool  requiresCopyBlock = false;
        bool  srcSingleLclVarAsg = false;

        // If either src or dest is a reg-sized non-field-addressed struct, keep the copyBlock.
        if ((destLclVar != nullptr && destLclVar->lvRegStruct) ||
            (srcLclVar  != nullptr && srcLclVar->lvRegStruct))
        {
            requiresCopyBlock = true;
        }

        // Can we use field by field assignment for the dest?
        if (destDoFldAsg && destLclVar->lvCustomLayout && destLclVar->lvContainsHoles)
        {
            JITDUMP(" dest contains custom layout and contains holes");
            // C++ style CopyBlock with holes
            requiresCopyBlock = true;
        }

        // Can we use field by field assignment for the src?
        if (srcDoFldAsg && srcLclVar->lvCustomLayout && srcLclVar->lvContainsHoles)
        {
            JITDUMP(" src contains custom layout and contains holes");
            // C++ style CopyBlock with holes
            requiresCopyBlock = true;
        }

        if (tree->OperGet() == GT_COPYBLK && tree->AsCpBlk()->gtBlkOpGcUnsafe)
        {
            requiresCopyBlock = true;
        }

        // If we passed the above checks, then we will check these two
        if (!requiresCopyBlock)
        {
            // Are both dest and src promoted structs? 
            if (destDoFldAsg && srcDoFldAsg)
            {
                // Both structs should be of the same type, if not we will use a copy block
                if (lvaTable[destLclNum].lvVerTypeInfo.GetClassHandle() != lvaTable[srcLclNum].lvVerTypeInfo.GetClassHandle())
                {
                    requiresCopyBlock = true;  // Mismatched types, leave as a CopyBlock
                    JITDUMP(" with mismatched types");
                }
            }
            // Are neither dest or src promoted structs? 
            else if (!destDoFldAsg && !srcDoFldAsg)  
            {
                requiresCopyBlock = true;   // Leave as a CopyBlock
                JITDUMP(" with no promoted structs");
            }
            else if (destDoFldAsg)
            {
                // Match the following kinds of trees:
                //  fgMorphTree BB01, stmt 9 (before)
                //   [000052] ------------        const     int    8
                //   [000053] -A--G-------     copyBlk   void  
                //   [000051] ------------           addr      byref 
                //   [000050] ------------              lclVar    long   V07 loc5         
                //   [000054] --------R---        <list>    void  
                //   [000049] ------------           addr      byref 
                //   [000048] ------------              lclVar    struct(P) V06 loc4         
                //                                              long   V06.h (offs=0x00) -> V17 tmp9
                // Yields this transformation
                //  fgMorphCopyBlock (after):
                //   [000050] ------------        lclVar    long   V07 loc5            
                //   [000085] -A----------     =         long  
                //   [000083] D------N----        lclVar    long   V17 tmp9         
                //
                if (blockWidthIsConst             && 
                    (destLclVar->lvFieldCnt == 1) && 
                    (srcLclVar != nullptr)        && 
                    (blockWidth == genTypeSize(srcLclVar->TypeGet())))
                {
                    // Reject the following tree:
                    //  - seen on x86chk    jit\jit64\hfa\main\hfa_sf3E_r.exe
                    //
                    //  fgMorphTree BB01, stmt 6 (before)
                    //   [000038] -------------        const     int    4
                    //   [000039] -A--G--------     copyBlk   void 
                    //   [000037] -------------           addr      byref 
                    //   [000036] -------------              lclVar    int    V05 loc3    
                    //   [000040] --------R----        <list>    void  
                    //   [000035] -------------           addr      byref 
                    //   [000034] -------------              lclVar    struct(P) V04 loc2        
                    //                                          float  V04.f1 (offs=0x00) -> V13 tmp6         
                    // As this would framsform into 
                    //   float V13 = int V05
                    //
                    unsigned fieldLclNum = lvaTable[destLclNum].lvFieldLclStart;
                    var_types destType = lvaTable[fieldLclNum].TypeGet();
                    if (srcLclVar->TypeGet() == destType)
                    {
                        srcSingleLclVarAsg = true;
                    }
                }
            }
        }

        // If we require a copy block the set both of the field assign bools to false
        if (requiresCopyBlock)
        {
            // If a copy block is required then we won't do field by field assignments
            destDoFldAsg = false;
            srcDoFldAsg = false;
        }

        JITDUMP(requiresCopyBlock ? " this requires a CopyBlock.\n" 
                                  : " using field by field assignments.\n");      

        // Mark the dest/src structs as DoNotEnreg 
        // when they are not reg-sized non-field-addressed structs and we are using a CopyBlock 
        // or the struct is not promoted 
        //    
        if (!destDoFldAsg && (destLclVar != nullptr))
        {
            if (!destLclVar->lvRegStruct)
            {
                // Mark it as DoNotEnregister.
                lvaSetVarDoNotEnregister(destLclNum DEBUGARG(DNER_BlockOp));
            }
        }

        if (!srcDoFldAsg && (srcLclVar != nullptr) && !srcSingleLclVarAsg)
        {
            if (!srcLclVar->lvRegStruct)
            {
                lvaSetVarDoNotEnregister(srcLclNum DEBUGARG(DNER_BlockOp));
            }
        }

        if (requiresCopyBlock)
        {
#if CPU_USES_BLOCK_MOVE
            compBlkOpUsed = true;
#endif
            // Note that the unrolling of CopyBlk is only implemented on some platforms
            // Currently that includes x64 and Arm64 but not x64 or Arm32
#ifdef CPBLK_UNROLL_LIMIT
            // If we have a CopyObj with a dest on the stack
            // we will convert it into an GC Unsafe CopyBlk that is non-interruptible
            // when its size is small enouch to be completely unrolled (i.e. between [16..64] bytes)
            //
            if (isCopyObj && destOnStack && blockWidthIsConst && 
                (blockWidth >= (2*TARGET_POINTER_SIZE)) && (blockWidth <= CPBLK_UNROLL_LIMIT))
            {
                tree->SetOper(GT_COPYBLK);
                tree->AsCpBlk()->gtBlkOpGcUnsafe = true;    // Mark as a GC unsage copy block
                blockSize->gtIntConCommon.SetIconValue(ssize_t(blockWidth));
                blockSize->gtFlags &= ~GTF_ICON_HDL_MASK;   // Clear the GTF_ICON_CLASS_HDL flags
            }
#endif
            // Liveness doesn't consider copyblk arguments of simple types as being
            // a use or def, so explicitly mark these variables as address-exposed.
            if (srcLclNum != BAD_VAR_NUM && !varTypeIsStruct(srcLclVar))
            {
                JITDUMP("Non-struct copyBlk src V%02d is addr exposed\n", srcLclNum);
                lvaTable[srcLclNum].lvAddrExposed = true;
            }

            if (destLclNum != BAD_VAR_NUM && !varTypeIsStruct(destLclVar))
            {
                JITDUMP("Non-struct copyBlk dest V%02d is addr exposed\n", destLclNum);
                lvaTable[destLclNum].lvAddrExposed = true;
            }

            goto _Done;
        }

        //
        // Otherwise we convert this CopyBlock into individual field by field assignments
        //
        tree = nullptr;

        GenTreePtr asg;
        GenTreePtr dest;
        GenTreePtr src;
        GenTreePtr addrSpill = nullptr;
        unsigned   addrSpillTemp = BAD_VAR_NUM;
        bool       addrSpillIsStackDest = false;   // true if 'addrSpill' represents the address in our local stack frame 

        unsigned    fieldCnt     = DUMMY_INIT(0);

        if (destDoFldAsg && srcDoFldAsg)
        {
            // To do fieldwise assignments for both sides, they'd better be the same struct type!
            // All of these conditions were checked above...
            assert(destLclNum != BAD_VAR_NUM && srcLclNum != BAD_VAR_NUM);
            assert(lvaTable[destLclNum].lvVerTypeInfo.GetClassHandle() == lvaTable[srcLclNum].lvVerTypeInfo.GetClassHandle());
            assert(destLclVar != nullptr && srcLclVar != nullptr && destLclVar->lvFieldCnt == srcLclVar->lvFieldCnt);

            fieldCnt = destLclVar->lvFieldCnt;
            goto _AssignFields; // No need to spill the address to the temp. Go ahead to morph it into field assignments.
        }
        else if (destDoFldAsg)
        {
            fieldCnt = destLclVar->lvFieldCnt;
        }
        else
        {
            assert(srcDoFldAsg);
            fieldCnt = srcLclVar->lvFieldCnt;
        }

        if (destDoFldAsg)
        {
            noway_assert(!srcDoFldAsg);
            if (gtClone(srcAddr))
            {
                // srcAddr is simple expression. No need to spill.
                noway_assert((srcAddr->gtFlags & GTF_PERSISTENT_SIDE_EFFECTS) == 0);
            }
            else
            {
                // srcAddr is complex expression. Clone and spill it (unless the destination is
                // a struct local that only has one field, in which case we'd only use the
                // address value once...)
                if (destLclVar->lvFieldCnt > 1)
                {
                    addrSpill = gtCloneExpr(srcAddr);     // addrSpill represents the 'srcAddr'
                    noway_assert(addrSpill != nullptr);
                }
            }
        }

        if (srcDoFldAsg)
        {
            noway_assert(!destDoFldAsg);

            // If we're doing field-wise stores, to an address within a local, and we copy
            // the address into "addrSpill", do *not* declare the original local var node in the
            // field address as GTF_VAR_DEF and GTF_VAR_USEASG; we will declare each of the
            // field-wise assignments as an "indirect" assignment to the local.
            // ("lclVarTree" is a subtree of "destAddr"; make sure we remove the flags before
            // we clone it.)
            if (lclVarTree != nullptr)
            {
                lclVarTree->gtFlags &= ~(GTF_VAR_DEF | GTF_VAR_USEASG);
            }

            if (gtClone(destAddr))
            {
                // destAddr is simple expression. No need to spill
                noway_assert((destAddr->gtFlags & GTF_PERSISTENT_SIDE_EFFECTS) == 0);
            }
            else
            {
                // destAddr is complex expression. Clone and spill it (unless
                // the source is a struct local that only has one field, in which case we'd only
                // use the address value once...)
                if (srcLclVar->lvFieldCnt > 1)
                {
                    addrSpill = gtCloneExpr(destAddr);    // addrSpill represents the 'destAddr'
                    noway_assert(addrSpill != nullptr);
                }

                // TODO-CQ: this should be based on a more general
                // "BaseAddress" method, that handles fields of structs, before or after
                // morphing.
                if (addrSpill != nullptr && addrSpill->OperGet() == GT_ADDR)
                {
                    if (addrSpill->gtOp.gtOp1->IsLocal())
                    {
                        // We will *not* consider this to define the local, but rather have each individual field assign
                        // be a definition.
                        addrSpill->gtOp.gtOp1->gtFlags &= ~(GTF_LIVENESS_MASK);
                        assert(lvaTable[addrSpill->gtOp.gtOp1->gtLclVarCommon.gtLclNum].lvLclBlockOpAddr == 1);                     
                        addrSpillIsStackDest = true;  // addrSpill represents the address of LclVar[varNum] in our local stack frame 
                    }
                }
            }
        }

        if (addrSpill != nullptr)
        {
            // Spill the (complex) address to a BYREF temp.
            // Note, at most one address may need to be spilled.
            addrSpillTemp = lvaGrabTemp(true DEBUGARG("BlockOp address local"));

            lvaTable[addrSpillTemp].lvType = TYP_BYREF;

            if (addrSpillIsStackDest)
            {
                lvaTable[addrSpillTemp].lvStackByref = true;
            }

            tree = gtNewAssignNode(gtNewLclvNode(addrSpillTemp, TYP_BYREF),
                                   addrSpill);

#ifndef LEGACY_BACKEND
            // If we are assigning the address of a LclVar here 
            // liveness does not account for this kind of address taken use. 
            // 
            // We have to mark this local as address exposed so
            // that we don't delete the definition for this LclVar 
            // as a dead store later on.
            //
            if (addrSpill->OperGet() == GT_ADDR)
            {
                GenTreePtr addrOp = addrSpill->gtOp.gtOp1;
                if (addrOp->IsLocal())
                {
                    unsigned lclVarNum = addrOp->gtLclVarCommon.gtLclNum;
                    lvaTable[lclVarNum].lvAddrExposed = true;
                    lvaSetVarDoNotEnregister(lclVarNum DEBUGARG(DNER_AddrExposed));
                }
            }
#endif // !LEGACY_BACKEND
        }

    _AssignFields:

        for (unsigned i=0; i<fieldCnt; ++i)
        {
            FieldSeqNode* curFieldSeq = nullptr;
            if (destDoFldAsg)
            {
                noway_assert(destLclNum != BAD_VAR_NUM);
                unsigned fieldLclNum = lvaTable[destLclNum].lvFieldLclStart + i;
                dest = gtNewLclvNode(fieldLclNum, lvaTable[fieldLclNum].TypeGet());

                noway_assert(destAddr->gtOp.gtOp1->gtOper == GT_LCL_VAR);
                // If it had been labeled a "USEASG", assignments to the the individual promoted fields are not.
                dest->gtFlags |= destAddr->gtOp.gtOp1->gtFlags & ~(GTF_NODE_MASK | GTF_VAR_USEASG);
            }
            else
            {
                noway_assert(srcDoFldAsg);
                noway_assert(srcLclNum != BAD_VAR_NUM);
                unsigned fieldLclNum = lvaTable[srcLclNum].lvFieldLclStart + i;

                if (addrSpill)
                {
                    assert(addrSpillTemp != BAD_VAR_NUM);
                    dest = gtNewLclvNode(addrSpillTemp, TYP_BYREF);
                }
                else
                {
                    dest = gtCloneExpr(destAddr);
                    noway_assert(dest != nullptr);

                    // Is the address of a local?
                    GenTreeLclVarCommon* lclVarTree = nullptr;
                    bool  isEntire = false;
                    bool* pIsEntire = (blockWidthIsConst ? &isEntire : nullptr);
                    if (dest->DefinesLocalAddr(this, blockWidth, &lclVarTree, pIsEntire))
                    {
                        lclVarTree->gtFlags |= GTF_VAR_DEF;
                        if (!isEntire)
                            lclVarTree->gtFlags |= GTF_VAR_USEASG;
                    }
                }

                GenTreePtr fieldOffsetNode = gtNewIconNode(lvaTable[fieldLclNum].lvFldOffset, TYP_I_IMPL);
                // Have to set the field sequence -- which means we need the field handle.
                CORINFO_CLASS_HANDLE classHnd = lvaTable[srcLclNum].lvVerTypeInfo.GetClassHandle();
                CORINFO_FIELD_HANDLE fieldHnd = info.compCompHnd->getFieldInClass(classHnd, lvaTable[fieldLclNum].lvFldOrdinal);
                curFieldSeq = GetFieldSeqStore()->CreateSingleton(fieldHnd);
                fieldOffsetNode->gtIntCon.gtFieldSeq = curFieldSeq;

                dest = gtNewOperNode(GT_ADD, TYP_BYREF,
                                     dest,
                                     fieldOffsetNode);

                dest = gtNewOperNode(GT_IND, lvaTable[fieldLclNum].TypeGet(), dest);

                // !!! The destination could be on stack. !!!
                // This flag will let us choose the correct write barrier.
                dest->gtFlags |= GTF_IND_TGTANYWHERE;
            }


            if (srcDoFldAsg)
            {
                noway_assert(srcLclNum != BAD_VAR_NUM);
                unsigned fieldLclNum = lvaTable[srcLclNum].lvFieldLclStart + i;
                src = gtNewLclvNode(fieldLclNum, lvaTable[fieldLclNum].TypeGet());

                noway_assert(srcAddr->gtOp.gtOp1->gtOper == GT_LCL_VAR);
                src->gtFlags |= srcAddr->gtOp.gtOp1->gtFlags & ~GTF_NODE_MASK;
            }
            else
            {
                noway_assert(destDoFldAsg);
                noway_assert(destLclNum != BAD_VAR_NUM);
                unsigned fieldLclNum = lvaTable[destLclNum].lvFieldLclStart + i;

                if (srcSingleLclVarAsg)
                {
                    noway_assert(fieldCnt == 1);
                    noway_assert(srcLclVar != nullptr);  
                    noway_assert(addrSpill == nullptr);

                    src = gtNewLclvNode(srcLclNum, srcLclVar->TypeGet());
                }
                else
                {
                    if (addrSpill)
                    {
                        assert(addrSpillTemp != BAD_VAR_NUM);
                        src = gtNewLclvNode(addrSpillTemp, TYP_BYREF);
                    }
                    else
                    {
                        src = gtCloneExpr(srcAddr);
                        noway_assert(src != nullptr);
                    }

                    CORINFO_CLASS_HANDLE classHnd = lvaTable[destLclNum].lvVerTypeInfo.GetClassHandle();
                    CORINFO_FIELD_HANDLE fieldHnd = info.compCompHnd->getFieldInClass(classHnd, lvaTable[fieldLclNum].lvFldOrdinal);
                    curFieldSeq = GetFieldSeqStore()->CreateSingleton(fieldHnd);

                    src = gtNewOperNode(GT_ADD, TYP_BYREF,
                                        src,
                                        new(this, GT_CNS_INT) GenTreeIntCon(TYP_I_IMPL,
                                                                            lvaTable[fieldLclNum].lvFldOffset,
                                                                            curFieldSeq));

                    src = gtNewOperNode(GT_IND, lvaTable[fieldLclNum].TypeGet(), src);
                }
            }

            noway_assert(dest->TypeGet() == src->TypeGet());

            asg = gtNewAssignNode(dest, src);

            // If we spilled the address, and we didn't do individual field assignments to promoted fields,
            // and it was of a local, record the assignment as an indirect update of a local.
            if (addrSpill && !destDoFldAsg && destLclNum != BAD_VAR_NUM)
            {
                curFieldSeq = GetFieldSeqStore()->Append(destFldSeq, curFieldSeq);
                bool isEntire = (genTypeSize(var_types(lvaTable[destLclNum].lvType))
                                 == genTypeSize(dest->TypeGet()));
                IndirectAssignmentAnnotation* pIndirAnnot =
                    new (this, CMK_Unknown) IndirectAssignmentAnnotation(destLclNum, curFieldSeq, isEntire);
                GetIndirAssignMap()->Set(asg, pIndirAnnot);
            }

#if LOCAL_ASSERTION_PROP
            if (optLocalAssertionProp)
            {
                optAssertionGen(asg);
            }
#endif // LOCAL_ASSERTION_PROP

            if (tree)
            {
                tree = gtNewOperNode(GT_COMMA,
                                     TYP_VOID,
                                     tree,
                                     asg);
            }
            else
            {
                tree = asg;
            }
        }
    }

    if (isLateArg)
    {
        tree->gtFlags |= GTF_LATE_ARG;
    }

#ifdef DEBUG
    tree->gtFlags |= GTF_MORPHED;

    if (verbose)
    {
        printf("\nfgMorphCopyBlock (after):\n");
        gtDispTree(tree);
    }
#endif

_Done:
    return tree;
}

// insert conversions and normalize to make tree amenable to register
// FP architectures
GenTree*  Compiler::fgMorphForRegisterFP(GenTree *tree)
{
    GenTreePtr      op1     = tree->gtOp.gtOp1;
    GenTreePtr      op2     = tree->gtGetOp2();

    if (tree->OperIsArithmetic()
        && varTypeIsFloating(tree))
    {
        if (op1->TypeGet() != tree->TypeGet())
        {
            tree->gtOp.gtOp1 = gtNewCastNode(tree->TypeGet(), tree->gtOp.gtOp1, tree->TypeGet());
        }
        if (op2->TypeGet() != tree->TypeGet())
        {
            tree->gtOp.gtOp2 = gtNewCastNode(tree->TypeGet(), tree->gtOp.gtOp2, tree->TypeGet());
        }
    }
    else if (tree->OperIsCompare()
             && varTypeIsFloating(op1)
             && op1->TypeGet() != op2->TypeGet())
    {
        // both had better be floating, just one bigger than other
        assert (varTypeIsFloating(op2));
        if (op1->TypeGet() == TYP_FLOAT)
        {
            tree->gtOp.gtOp1 = gtNewCastNode(TYP_DOUBLE, tree->gtOp.gtOp1, TYP_DOUBLE);
        }
        else if (op2->TypeGet() == TYP_FLOAT)
        {
            tree->gtOp.gtOp2 = gtNewCastNode(TYP_DOUBLE, tree->gtOp.gtOp2, TYP_DOUBLE);
        }
    }

    return tree;
}

GenTree* Compiler::fgMorphRecognizeBoxNullable(GenTree* compare)
{
    GenTree* op1 = compare->gtOp.gtOp1;
    GenTree* op2 = compare->gtOp.gtOp2;
    GenTree* opCns;
    GenTreeCall* opCall;

    // recognize this pattern:
    //
    // stmtExpr  void  (IL 0x000...  ???)
    //     return    int
    //             const     ref    null
    //         ==        int
    //             call help ref    HELPER.CORINFO_HELP_BOX_NULLABLE
    //                 const(h)  long   0x7fed96836c8 class
    //                 addr      byref
    //                     ld.lclVar struct V00 arg0
    //
    //
    // which comes from this code (reported by customer as being slow) :
    //
    // private static bool IsNull<T>(T arg)
    // {
    //    return arg==null;
    // }
    //

    if (op1->IsCnsIntOrI() && op2->IsHelperCall())
    {
        opCns = op1;
        opCall = op2->AsCall();
    }
    else if (op1->IsHelperCall() && op2->IsCnsIntOrI())
    {
        opCns = op2;
        opCall = op1->AsCall();
    }
    else
    {
        return compare;
    }

    if (opCns->gtIntConCommon.IconValue() != 0)
        return compare;

    if (eeGetHelperNum(opCall->gtCallMethHnd) != CORINFO_HELP_BOX_NULLABLE)
        return compare;

    // replace the box with an access of the nullable 'hasValue' field which is at the zero offset
    GenTree* newOp = gtNewOperNode(GT_IND, TYP_BOOL, opCall->gtCall.gtCallArgs->gtOp.gtOp2->gtOp.gtOp1);

    if (opCall == op1)
        compare->gtOp.gtOp1 = newOp;
    else
        compare->gtOp.gtOp2 = newOp;

    return compare;
}

#ifdef FEATURE_SIMD

//--------------------------------------------------------------------------------------
// fgCopySIMDNode: make a copy of a SIMD intrinsic node, e.g. so that a field can be accessed.
//
// Arguments:
//    simdNode  - The GenTreeSIMD node to be copied
//
// Return Value:
//    A comma node where op1 is the assignment of the simd node to a temp, and op2 is the temp lclVar.
//
GenTree*
Compiler::fgCopySIMDNode(GenTreeSIMD* simdNode)
{
    // Copy the result of the SIMD intrinsic into a temp.
    unsigned lclNum = lvaGrabTemp(true DEBUGARG("Copy of SIMD intrinsic with field access"));

    CORINFO_CLASS_HANDLE simdHandle = NO_CLASS_HANDLE;
    // We only have fields of the fixed float vectors.
    noway_assert(simdNode->gtSIMDBaseType == TYP_FLOAT);
    switch(simdNode->gtSIMDSize)
    {
    case 8:     simdHandle = SIMDVector2Handle;                 break;
    case 12:    simdHandle = SIMDVector3Handle;                 break;
    case 16:    simdHandle = SIMDVector4Handle;                 break;
    default:    noway_assert(!"field of unexpected SIMD type"); break;
    }
    assert(simdHandle != NO_CLASS_HANDLE);

    lvaSetStruct(lclNum, simdHandle, false, true);
    lvaTable[lclNum].lvFieldAccessed = true;

    GenTree* asg = gtNewTempAssign(lclNum, simdNode);
    GenTree* newLclVarNode = new (this, GT_LCL_VAR) GenTreeLclVar(simdNode->TypeGet(), lclNum, BAD_IL_OFFSET);
   
    GenTree* comma = gtNewOperNode(GT_COMMA, simdNode->TypeGet(), asg, newLclVarNode);
    return comma;
}

//--------------------------------------------------------------------------------------------------------------
// getSIMDStructFromField: 
//   Checking whether the field belongs to a simd struct or not. If it is, return the GenTreePtr for 
//   the struct node, also base type, field index and simd size. If it is not, just return  nullptr.
//   Usually if the tree node is from a simd lclvar which is not used in any SIMD intrinsic, then we 
//   should return nullptr, since in this case we should treat SIMD struct as a regular struct. 
//   However if no matter what, you just want get simd struct node, you can set the ignoreUsedInSIMDIntrinsic
//   as true. Then there will be no IsUsedInSIMDIntrinsic checking, and it will return SIMD struct node
//   if the struct is a SIMD struct.
//
// Arguments:
//       tree - GentreePtr. This node will be checked to see this is a field which belongs to a simd 
//               struct used for simd intrinsic or not.
//       pBaseTypeOut - var_types pointer, if the tree node is the tree we want, we set *pBaseTypeOut 
//                      to simd lclvar's base type.
//       indexOut - unsigned pointer, if the tree is used for simd intrinsic, we will set *indexOut 
//                  equals to the index number of this field.
//       simdSizeOut - unsigned pointer, if the tree is used for simd intrinsic, set the *simdSizeOut 
//                     equals to the simd struct size which this tree belongs to.   
//      ignoreUsedInSIMDIntrinsic - bool. If this is set to true, then this function will ignore 
//                                  the UsedInSIMDIntrinsic check.
//
// return value:
//       A GenTreePtr which points the simd lclvar tree belongs to. If the tree is not the simd 
//       instrinic related field, return nullptr. 
//

GenTreePtr Compiler::getSIMDStructFromField(GenTreePtr tree, var_types* pBaseTypeOut, unsigned* indexOut, unsigned* simdSizeOut, bool ignoreUsedInSIMDIntrinsic/*false*/)
{
    GenTreePtr ret = nullptr;
    if(tree->OperGet() == GT_FIELD)
    {
        GenTreePtr objRef = tree->gtField.gtFldObj;
        if (objRef != nullptr)
        {
            GenTreePtr obj = nullptr;
            if (objRef->gtOper == GT_ADDR)
            {
                obj = objRef->gtOp.gtOp1;
            }
            else if(ignoreUsedInSIMDIntrinsic)
            {
                obj = objRef;
            }
            else
            {
                return nullptr;
            }
            
            if (isSIMDTypeLocal(obj))
            {
                unsigned    lclNum = obj->gtLclVarCommon.gtLclNum;
                LclVarDsc*  varDsc = &lvaTable[lclNum];
                if(varDsc->lvIsUsedInSIMDIntrinsic() || ignoreUsedInSIMDIntrinsic)
                {
                    *simdSizeOut = varDsc->lvExactSize;
                    *pBaseTypeOut = getBaseTypeOfSIMDLocal(obj);
                    ret = obj;
                }
            }
            else if (obj->OperGet() == GT_SIMD)
            {
                ret = obj;
                GenTreeSIMD* simdNode = obj->AsSIMD();
                *simdSizeOut = simdNode->gtSIMDSize;
                *pBaseTypeOut = simdNode->gtSIMDBaseType;
            }
        }
    }
    if (ret != nullptr)
    {
        unsigned BaseTypeSize = genTypeSize(*pBaseTypeOut);
        *indexOut = tree->gtField.gtFldOffset / BaseTypeSize;
    }
    return ret;
}   
  
/*****************************************************************************
*  If a read operation tries to access simd struct field, then transform the this
*  operation to to the SIMD intrinsic SIMDIntrinsicGetItem, and return the new tree. 
*  Otherwise, return the old tree. 
*  Argument:
*   tree - GenTreePtr. If this pointer points to simd struct which is used for simd 
*          intrinsic. We will morph it as simd intrinsic SIMDIntrinsicGetItem. 
*  Return:
*   A GenTreePtr which points to the new tree. If the tree is not for simd intrinsic,
*   return nullptr. 
*/

GenTreePtr Compiler::fgMorphFieldToSIMDIntrinsicGet(GenTreePtr tree)
{
    unsigned index = 0;
    var_types baseType = TYP_UNKNOWN; 
    unsigned simdSize = 0;
    GenTreePtr simdStructNode = getSIMDStructFromField(tree, &baseType, &index, &simdSize);
    if(simdStructNode != nullptr)
    {
        
        assert(simdSize >= ((index + 1) * genTypeSize(baseType)));
        GenTree* op2 = gtNewIconNode(index);   
        tree =  gtNewSIMDNode(baseType, simdStructNode, op2, SIMDIntrinsicGetItem, baseType, simdSize); 
#ifdef DEBUG
        tree->gtFlags |= GTF_MORPHED;
#endif
    }
    return tree;
}    

/*****************************************************************************
*  Transform an assignment of a SIMD struct field to SIMD intrinsic 
*  SIMDIntrinsicGetItem, and return a new tree. If If it is not such an assignment,
*  then return the old tree. 
*  Argument:
*   tree - GenTreePtr. If this pointer points to simd struct which is used for simd 
*          intrinsic. We will morph it as simd intrinsic set. 
*  Return:
*   A GenTreePtr which points to the new tree. If the tree is not for simd intrinsic,
*   return nullptr. 
*/

GenTreePtr  Compiler::fgMorphFieldAssignToSIMDIntrinsicSet(GenTreePtr tree)
{
    assert(tree->OperGet() == GT_ASG);
    GenTreePtr op1 = tree->gtGetOp1();
    GenTreePtr op2 = tree->gtGetOp2();
    
    unsigned index = 0;
    var_types baseType = TYP_UNKNOWN; 
    unsigned simdSize = 0;
    GenTreePtr simdOp1Struct = getSIMDStructFromField(op1, &baseType, &index, &simdSize);
    if (simdOp1Struct != nullptr)
    {
        //Generate the simd set intrinsic
        assert(simdSize >= ((index + 1) * genTypeSize(baseType)));
        
        SIMDIntrinsicID simdIntrinsicID = SIMDIntrinsicInvalid;     
        switch (index)
        {
        case 0:
            simdIntrinsicID = SIMDIntrinsicSetX;
            break;
        case 1:
            simdIntrinsicID = SIMDIntrinsicSetY;
            break;
        case 2:
            simdIntrinsicID = SIMDIntrinsicSetZ;
            break;
        case 3: 
            simdIntrinsicID = SIMDIntrinsicSetW;
            break;
        default:
            noway_assert("There is no set intrinsic for index bigger than 3");
        }
        

        GenTreePtr newStruct = gtClone(simdOp1Struct);
        assert((newStruct != nullptr) && (varTypeIsSIMD(newStruct)));
        GenTreePtr simdTree = gtNewSIMDNode(newStruct->gtType, simdOp1Struct, op2, simdIntrinsicID, baseType, simdSize);
        GenTreePtr copyBlkDst = gtNewOperNode(GT_ADDR, TYP_BYREF, newStruct);
        tree = gtNewBlkOpNode(GT_COPYBLK,
                            copyBlkDst,
                            gtNewOperNode(GT_ADDR, TYP_BYREF,  simdTree),
                            gtNewIconNode(simdSize),
                            false);
#ifdef DEBUG
        tree->gtFlags |= GTF_MORPHED;
#endif
    }
    
    return tree;
}

#endif
/*****************************************************************************
 *
 *  Transform the given GTK_SMPOP tree for code generation.
 */

#ifdef _PREFAST_
#pragma warning(push)
#pragma warning(disable:21000) // Suppress PREFast warning about overly large function
#endif
GenTreePtr          Compiler::fgMorphSmpOp(GenTreePtr tree, MorphAddrContext* mac)
{
    // this extra scope is a workaround for a gcc bug
    // the inline destructor for ALLOCA_CHECK confuses the control
    // flow and gcc thinks that the function never returns
    {
    ALLOCA_CHECK();
    noway_assert(tree->OperKind() & GTK_SMPOP);

    /* The steps in this function are :
       o Perform required preorder processing
       o Process the first, then second operand, if any
       o Perform required postorder morphing
       o Perform optional postorder morphing if optimizing
     */

    bool            isQmarkColon     = false;

#if LOCAL_ASSERTION_PROP
    AssertionIndex  origAssertionCount = DUMMY_INIT(0);
    AssertionDsc *  origAssertionTab   = DUMMY_INIT(NULL);

    AssertionIndex  thenAssertionCount = DUMMY_INIT(0);
    AssertionDsc *  thenAssertionTab   = DUMMY_INIT(NULL);
#endif

    if (fgGlobalMorph)
    {
#if !FEATURE_STACK_FP_X87
        tree = fgMorphForRegisterFP(tree);
#endif
    }

    genTreeOps      oper    = tree->OperGet();
    var_types       typ     = tree->TypeGet();
    GenTreePtr      op1     = tree->gtOp.gtOp1;
    GenTreePtr      op2     = tree->gtGetOp2();

    /*-------------------------------------------------------------------------
     * First do any PRE-ORDER processing
     */

    switch (oper)
    {
        // Some arithmetic operators need to use a helper call to the EE
        int         helper;

    case GT_ASG:
        tree = fgDoNormalizeOnStore(tree);
        /* fgDoNormalizeOnStore can change op2 */
        noway_assert(op1 == tree->gtOp.gtOp1);
        op2 = tree->gtOp.gtOp2;

#ifdef FEATURE_SIMD
        {
            // We should check whether op2 should be assigned to a SIMD field or not.
            // if it is, we should tranlate the tree to simd intrinsic
            GenTreePtr newTree = fgMorphFieldAssignToSIMDIntrinsicSet(tree);
            if (newTree != tree)
            {
                tree = newTree;
                oper    = tree->OperGet();
                typ     = tree->TypeGet();
                op1 = tree->gtOp.gtOp1;
                op2 = tree->gtGetOp2();
            }
        }        
#endif

        __fallthrough;

    case GT_ASG_ADD:
    case GT_ASG_SUB:
    case GT_ASG_MUL:
    case GT_ASG_DIV:
    case GT_ASG_MOD:
    case GT_ASG_UDIV:
    case GT_ASG_UMOD:
    case GT_ASG_OR:
    case GT_ASG_XOR:
    case GT_ASG_AND:
    case GT_ASG_LSH:
    case GT_ASG_RSH:
    case GT_ASG_RSZ:
    case GT_CHS:

        /* We can't CSE the LHS of an assignment. Only r-values can be CSEed */
        op1->gtFlags |= GTF_DONT_CSE;
        break;

    case GT_ADDR:

        /* op1 of a GT_ADDR is an l-value. Only r-values can be CSEed */
        op1->gtFlags |= GTF_DONT_CSE;
        break;

    case GT_QMARK:
    case GT_JTRUE:

        noway_assert(op1);

        if (op1->OperKind() & GTK_RELOP)
        {
            noway_assert((oper == GT_JTRUE) || (op1->gtFlags & GTF_RELOP_QMARK));
            /* Mark the comparison node with GTF_RELOP_JMP_USED so it knows that it does
               not need to materialize the result as a 0 or 1. */

            /* We also mark it as DONT_CSE, as we don't handle QMARKs with nonRELOP op1s */
            op1->gtFlags |= (GTF_RELOP_JMP_USED | GTF_DONT_CSE);

            // Request that the codegen for op1 sets the condition flags
            // when it generates the code for op1.
            //
            // Codegen for op1 must set the condition flags if
            // this method returns true.
            //
            op1->gtRequestSetFlags();
        }
        else
        {
            GenTreePtr effOp1 = op1->gtEffectiveVal();
            
            noway_assert( (effOp1->gtOper == GT_CNS_INT) &&
                         ((effOp1->gtIntCon.gtIconVal == 0) || (effOp1->gtIntCon.gtIconVal == 1)) );
        }
        break;

    case GT_COLON:
#if LOCAL_ASSERTION_PROP
        if (optLocalAssertionProp)
#endif
            isQmarkColon = true;
        break;

    case GT_INDEX:
        return fgMorphArrayIndex(tree);

    case GT_CAST:
        return fgMorphCast(tree);

    case GT_MUL:

#ifndef _TARGET_64BIT_
#if !LONG_MATH_REGPARAM
        if  (typ == TYP_LONG)
        {
            /* For (long)int1 * (long)int2, we dont actually do the
               casts, and just multiply the 32 bit values, which will
               give us the 64 bit result in edx:eax */

            noway_assert(op2);
            if  ((op1->gtOper                                 == GT_CAST &&
                  op2->gtOper                                 == GT_CAST &&
                  genActualType(op1->CastFromType()) == TYP_INT &&
                  genActualType(op2->CastFromType()) == TYP_INT)&&
                  !op1->gtOverflow() && !op2->gtOverflow())
            {
                // The casts have to be of the same signedness.
                if ((op1->gtFlags & GTF_UNSIGNED) != (op2->gtFlags & GTF_UNSIGNED))
                {
                    //We see if we can force an int constant to change its signedness
                    GenTreePtr constOp;
                    if (op1->gtCast.CastOp()->gtOper == GT_CNS_INT)
                        constOp = op1;
                    else if (op2->gtCast.CastOp()->gtOper == GT_CNS_INT)
                        constOp = op2;
                    else
                        goto NO_MUL_64RSLT;

                    if ( ((unsigned)(constOp->gtCast.CastOp()->gtIntCon.gtIconVal) < (unsigned)(0x80000000)) )
                        constOp->gtFlags ^=  GTF_UNSIGNED;
                    else
                        goto NO_MUL_64RSLT;
                }

                // The only combination that can overflow
                if (tree->gtOverflow() && (tree->gtFlags & GTF_UNSIGNED) &&
                                         !( op1->gtFlags & GTF_UNSIGNED))
                    goto NO_MUL_64RSLT;

                /* Remaining combinations can never overflow during long mul. */

                tree->gtFlags &= ~GTF_OVERFLOW;

                /* Do unsigned mul only if the casts were unsigned */

                tree->gtFlags &= ~GTF_UNSIGNED;
                tree->gtFlags |= op1->gtFlags & GTF_UNSIGNED;

                /* Since we are committing to GTF_MUL_64RSLT, we don't want
                   the casts to be folded away. So morph the castees directly */

                op1->gtOp.gtOp1 = fgMorphTree(op1->gtOp.gtOp1);
                op2->gtOp.gtOp1 = fgMorphTree(op2->gtOp.gtOp1);

                // Propagate side effect flags up the tree
                op1->gtFlags &= ~GTF_ALL_EFFECT;
                op1->gtFlags |= (op1->gtOp.gtOp1->gtFlags & GTF_ALL_EFFECT);
                op2->gtFlags &= ~GTF_ALL_EFFECT;
                op2->gtFlags |= (op2->gtOp.gtOp1->gtFlags & GTF_ALL_EFFECT);

                // If the GT_MUL can be altogether folded away, we should do that.

                if ((op1->gtCast.CastOp()->OperKind() &
                     op2->gtCast.CastOp()->OperKind() & GTK_CONST) && opts.OptEnabled(CLFLG_CONSTANTFOLD))
                {
                    tree->gtOp.gtOp1 = op1 = gtFoldExprConst(op1);
                    tree->gtOp.gtOp2 = op2 = gtFoldExprConst(op2);
                    noway_assert(op1->OperKind() & op2->OperKind() & GTK_CONST);
                    tree = gtFoldExprConst(tree);
                    noway_assert(tree->OperIsConst());
                    return tree;
                }

                tree->gtFlags |= GTF_MUL_64RSLT;

                // If op1 and op2 are unsigned casts, we need to do an unsigned mult
                tree->gtFlags |= (op1->gtFlags & GTF_UNSIGNED);

                // Insert GT_NOP nodes for the cast operands so that they do not get folded
                // And propagate the new flags. We don't want to CSE the casts because
                // codegen expects GTF_MUL_64RSLT muls to have a certain layout.

                if  (op1->gtCast.CastOp()->OperGet() != GT_NOP)
                {
                    op1->gtOp.gtOp1 = gtNewOperNode(GT_NOP, TYP_INT, op1->gtCast.CastOp());
                    op1->gtFlags  &= ~GTF_ALL_EFFECT;
                    op1->gtFlags  |= (op1->gtCast.CastOp()->gtFlags & GTF_ALL_EFFECT);
                    op1->gtFlags  |= GTF_DONT_CSE;
                }

                if (op2->gtCast.CastOp()->OperGet() != GT_NOP)
                {
                    op2->gtOp.gtOp1 = gtNewOperNode(GT_NOP, TYP_INT, op2->gtCast.CastOp());
                    op2->gtFlags  &= ~GTF_ALL_EFFECT;
                    op2->gtFlags  |= (op2->gtCast.CastOp()->gtFlags & GTF_ALL_EFFECT);
                    op2->gtFlags  |= GTF_DONT_CSE;
                }

                tree->gtFlags &= ~GTF_ALL_EFFECT;
                tree->gtFlags |= ((op1->gtFlags | op2->gtFlags) & GTF_ALL_EFFECT);

                goto DONE_MORPHING_CHILDREN;
            }
            else if ((tree->gtFlags & GTF_MUL_64RSLT) == 0)
            {
NO_MUL_64RSLT:
                if (tree->gtOverflow())
                    helper = (tree->gtFlags & GTF_UNSIGNED) ? CORINFO_HELP_ULMUL_OVF
                                                            : CORINFO_HELP_LMUL_OVF;
                else
                    helper = CORINFO_HELP_LMUL;

                goto USE_HELPER_FOR_ARITH;
            }
            else
            {
                /* We are seeing this node again. We have decided to use
                   GTF_MUL_64RSLT, so leave it alone. */

                assert(tree->gtIsValid64RsltMul());
            }
        }
#endif // !LONG_MATH_REGPARAM
#endif // !_TARGET_64BIT_
        break;


    case GT_DIV:

#ifndef _TARGET_64BIT_
#if !LONG_MATH_REGPARAM
        if  (typ == TYP_LONG)
        {
            helper = CORINFO_HELP_LDIV;
            goto USE_HELPER_FOR_ARITH;
        }
#endif

#if  USE_HELPERS_FOR_INT_DIV
        if  (typ == TYP_INT && !fgIsSignedDivOptimizable(op2))
        {
            helper = CORINFO_HELP_DIV;
            goto USE_HELPER_FOR_ARITH;
        }
#endif
#endif // !_TARGET_64BIT_

#ifndef LEGACY_BACKEND
        if (op2->gtOper == GT_CAST && op2->gtOp.gtOp1->IsCnsIntOrI())
        {
            op2 = gtFoldExprConst(op2);
        }
        
        if (fgShouldUseMagicNumberDivide(tree->AsOp()))
        {
            tree = fgMorphDivByConst(tree->AsOp());
            op1 = tree->gtOp.gtOp1;
            op2 = tree->gtOp.gtOp2; 
        }
#endif // !LEGACY_BACKEND
        break;


    case GT_UDIV:

#ifndef _TARGET_64BIT_
#if !LONG_MATH_REGPARAM
        if  (typ == TYP_LONG)
        {
            helper = CORINFO_HELP_ULDIV;
            goto USE_HELPER_FOR_ARITH;
        }
#endif
#if  USE_HELPERS_FOR_INT_DIV
        if  (typ == TYP_INT && !fgIsUnsignedDivOptimizable(op2))
        {
            helper = CORINFO_HELP_UDIV;
            goto USE_HELPER_FOR_ARITH;
        }
#endif
#endif // _TARGET_64BIT_
        break;


    case GT_MOD:

        if  (varTypeIsFloating(typ))
        {
            helper = CORINFO_HELP_DBLREM;
            noway_assert(op2);
            if (op1->TypeGet() == TYP_FLOAT)
                if (op2->TypeGet() == TYP_FLOAT)
                    helper = CORINFO_HELP_FLTREM;
                else
                    tree->gtOp.gtOp1 = op1 = gtNewCastNode(TYP_DOUBLE, op1, TYP_DOUBLE);
            else
                if (op2->TypeGet() == TYP_FLOAT)
                    tree->gtOp.gtOp2 = op2 = gtNewCastNode(TYP_DOUBLE, op2, TYP_DOUBLE);
            goto USE_HELPER_FOR_ARITH;
        }

        // Do not use optimizations (unlike UMOD's idiv optimizing during codegen) for signed mod.
        // A similar optimization for signed mod will not work for a negative perfectly divisible
        // HI-word. To make it correct, we would need to divide without the sign and then flip the
        // result sign after mod. This requires 18 opcodes + flow making it not worthy to inline.
        goto ASSIGN_HELPER_FOR_MOD;

    case GT_UMOD:

#ifdef _TARGET_ARMARCH_
        //
        // Note for _TARGET_ARMARCH_ we don't have  a remainder instruction, so we don't do this optimization
        //
#else // _TARGET_XARCH
        /* If this is an unsigned long mod with op2 which is a cast to long from a
           constant int, then don't morph to a call to the helper.  This can be done
           faster inline using idiv.
        */

        noway_assert(op2);
        if ((typ == TYP_LONG) && opts.OptEnabled(CLFLG_CONSTANTFOLD) &&
            ((tree->gtFlags & GTF_UNSIGNED) == (op1->gtFlags & GTF_UNSIGNED)) &&
            ((tree->gtFlags & GTF_UNSIGNED) == (op2->gtFlags & GTF_UNSIGNED)))
        {
            if (op2->gtOper == GT_CAST                                 &&
                op2->gtCast.CastOp()->gtOper == GT_CNS_INT             &&
                op2->gtCast.CastOp()->gtIntCon.gtIconVal >= 2          &&
                op2->gtCast.CastOp()->gtIntCon.gtIconVal <= 0x3fffffff &&
                (tree->gtFlags & GTF_UNSIGNED) == (op2->gtCast.CastOp()->gtFlags & GTF_UNSIGNED))
            {
                tree->gtOp.gtOp2 = op2 = fgMorphCast(op2);
                noway_assert(op2->gtOper == GT_CNS_NATIVELONG);
            }

            if (op2->gtOper == GT_CNS_NATIVELONG             &&
                op2->gtIntConCommon.LngValue() >= 2          &&
                op2->gtIntConCommon.LngValue() <= 0x3fffffff)
            {
                tree->gtOp.gtOp1 = op1 = fgMorphTree(op1);
                noway_assert(op1->TypeGet() == TYP_LONG);

                // Update flags for op1 morph
                tree->gtFlags &= ~GTF_ALL_EFFECT;

                tree->gtFlags |= (op1->gtFlags & GTF_ALL_EFFECT); // Only update with op1 as op2 is a constant

                // If op1 is a constant, then do constant folding of the division operator
                if (op1->gtOper == GT_CNS_NATIVELONG)
                {
                    tree = gtFoldExpr(tree);
                }
                return tree;
            }
        }
#endif // _TARGET_XARCH

    ASSIGN_HELPER_FOR_MOD:

        // For "val % 1", return 0 if op1 doesn't have any side effects
        // and we are not in the CSE phase, we cannot discard 'tree'
        // because it may contain CSE expressions that we haven't yet examined.
        //
        if (((op1->gtFlags & GTF_SIDE_EFFECT) == 0) && !optValnumCSE_phase)
        {
            if (((op2->gtOper == GT_CNS_INT) && (op2->gtIntConCommon.IconValue() == 1))
                || ((op2->gtOper == GT_CNS_LNG) && (op2->gtIntConCommon.LngValue() == 1)))
            {
                GenTreePtr zeroNode = gtNewZeroConNode(typ);
#ifdef DEBUG
                zeroNode->gtFlags |= GTF_MORPHED;
#endif
                DEBUG_DESTROY_NODE(tree);
                return zeroNode;
            }
        }

#ifndef  _TARGET_64BIT_
#if !LONG_MATH_REGPARAM
        if  (typ == TYP_LONG)
        {
            helper = (oper == GT_UMOD) ? CORINFO_HELP_ULMOD : CORINFO_HELP_LMOD;
            goto USE_HELPER_FOR_ARITH;
        }
#endif

#if  USE_HELPERS_FOR_INT_DIV
        if  (typ == TYP_INT)
        {
            if (oper == GT_UMOD && !fgIsUnsignedModOptimizable(op2))
            {
                helper = CORINFO_HELP_UMOD;
                goto USE_HELPER_FOR_ARITH;
            }
            else if (oper == GT_MOD && !fgIsSignedModOptimizable(op2))
            {
                helper = CORINFO_HELP_MOD;
                goto USE_HELPER_FOR_ARITH;
            }
        }
#endif
#endif // !_TARGET_64BIT_

#ifndef LEGACY_BACKEND
        if (op2->gtOper == GT_CAST && op2->gtOp.gtOp1->IsCnsIntOrI())
        {
            op2 = gtFoldExprConst(op2);
        }

#ifdef _TARGET_ARM64_

        // For ARM64 we don't have a remainder instruction,
        // The architecture manual suggests the following transformation to 
        // generate code for such operator:
        //
        // a % b = a - (a / b) * b;
        //
        tree = fgMorphModToSubMulDiv(tree->AsOp());
        op1 = tree->gtOp.gtOp1;
        op2 = tree->gtOp.gtOp2;

#else  // !_TARGET_ARM64_

        if (oper != GT_UMOD && fgShouldUseMagicNumberDivide(tree->AsOp()))
        {
            tree = fgMorphModByConst(tree->AsOp());
            op1 = tree->gtOp.gtOp1;
            op2 = tree->gtOp.gtOp2; 
        }

#endif //_TARGET_ARM64_
#endif // !LEGACY_BACKEND
        break;

    USE_HELPER_FOR_ARITH:
        {
            /* We have to morph these arithmetic operations into helper calls
               before morphing the arguments (preorder), else the arguments
               won't get correct values of fgPtrArgCntCur.
               However, try to fold the tree first in case we end up with a
               simple node which won't need a helper call at all */

            noway_assert(tree->OperIsBinary());

            GenTreePtr oldTree = tree;

            tree = gtFoldExpr(tree);

            // Were we able to fold it ?
            // Note that gtFoldExpr may return a non-leaf even if successful
            // e.g. for something like "expr / 1" - see also bug #290853
            if (tree->OperIsLeaf() || (oldTree != tree))

            {
                return (oldTree != tree) ? fgMorphTree(tree) : fgMorphLeaf(tree);
            }

            // Did we fold it into a comma node with throw?
            if (tree->gtOper == GT_COMMA)
            {
                noway_assert(fgIsCommaThrow(tree));
                return fgMorphTree(tree);
            }
        }
        return fgMorphIntoHelperCall(tree, helper, gtNewArgList(op1, op2));

    case GT_RETURN:
        // normalize small integer return values
        if (fgGlobalMorph && varTypeIsSmall(info.compRetType) &&
            (op1 != NULL) && (op1->TypeGet() != TYP_VOID) &&
            fgCastNeeded(op1, info.compRetType))
        {
            // Small-typed return values are normalized by the callee
            op1 = gtNewCastNode(TYP_INT, op1, info.compRetType);

            // Propagate GTF_COLON_COND
            op1->gtFlags|=(tree->gtFlags & GTF_COLON_COND);

            tree->gtOp.gtOp1 = fgMorphCast(op1);

            // Propagate side effect flags
            tree->gtFlags &= ~GTF_ALL_EFFECT;
            tree->gtFlags |= (tree->gtOp.gtOp1->gtFlags & GTF_ALL_EFFECT);

            return tree;
        }
        break;

    case GT_EQ:
    case GT_NE:

        // Check for typeof(...) == obj.GetType()
        // Also check for typeof(...) == typeof(...)
        // IMPORTANT NOTE: this optimization relies on a one-to-one mapping between
        // type handles and instances of System.Type
        // If this invariant is ever broken, the optimization will need updating

#ifdef LEGACY_BACKEND
        if ( op1->gtOper == GT_CALL &&
            op2->gtOper == GT_CALL &&
            ((op1->gtCall.gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC) || (op1->gtCall.gtCallType == CT_HELPER)) &&
            ((op2->gtCall.gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC) || (op2->gtCall.gtCallType == CT_HELPER)))
#else
        if ((((op1->gtOper == GT_INTRINSIC) && (op1->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Object_GetType)) || 
             ((op1->gtOper == GT_CALL) && (op1->gtCall.gtCallType == CT_HELPER))) &&
            (((op2->gtOper == GT_INTRINSIC) && (op2->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Object_GetType)) ||
             ((op2->gtOper == GT_CALL) && (op2->gtCall.gtCallType == CT_HELPER))))
#endif
        {
            GenTreePtr  pGetClassFromHandle;
            GenTreePtr  pGetType;

#ifdef LEGACY_BACKEND
            bool bOp1ClassFromHandle = gtIsTypeHandleToRuntimeTypeHelper(op1);
            bool bOp2ClassFromHandle = gtIsTypeHandleToRuntimeTypeHelper(op2);
#else
            bool bOp1ClassFromHandle = op1->gtOper == GT_CALL ? gtIsTypeHandleToRuntimeTypeHelper(op1) : false;
            bool bOp2ClassFromHandle = op2->gtOper == GT_CALL ? gtIsTypeHandleToRuntimeTypeHelper(op2) : false;
#endif

            // Optimize typeof(...) == typeof(...)
            // Typically this occurs in generic code that attempts a type switch
            // e.g. typeof(T) == typeof(int)

            if (bOp1ClassFromHandle && bOp2ClassFromHandle)
            {
                GenTreePtr classFromHandleArg1 = tree->gtOp.gtOp1->gtCall.gtCallArgs->gtOp.gtOp1;
                GenTreePtr classFromHandleArg2 = tree->gtOp.gtOp2->gtCall.gtCallArgs->gtOp.gtOp1;

                GenTreePtr compare = gtNewOperNode(oper, TYP_INT,
                                                   classFromHandleArg1,
                                                   classFromHandleArg2);

                compare->gtFlags |= tree->gtFlags & (GTF_RELOP_JMP_USED | GTF_RELOP_QMARK | GTF_DONT_CSE);

                // Morph and return
                return fgMorphTree(compare);
            }
            else if (bOp1ClassFromHandle || bOp2ClassFromHandle)
            {
                //
                // Now check for GetClassFromHandle(handle) == obj.GetType()
                //

                if (bOp1ClassFromHandle)
                {
                    pGetClassFromHandle = tree->gtOp.gtOp1;
                    pGetType = op2;
                }
                else
                {
                    pGetClassFromHandle = tree->gtOp.gtOp2;
                    pGetType = op1;
                }

                GenTreePtr pGetClassFromHandleArgument = pGetClassFromHandle->gtCall.gtCallArgs->gtOp.gtOp1;
                GenTreePtr pConstLiteral = pGetClassFromHandleArgument;

                // Unwrap GT_NOP node used to prevent constant folding
                if (pConstLiteral->gtOper == GT_NOP && pConstLiteral->gtType == TYP_I_IMPL)
                {
                    pConstLiteral = pConstLiteral->gtOp.gtOp1;
                }

                // In the ngen case, we have to go thru an indirection to get the right handle.
                if (pConstLiteral->gtOper == GT_IND)
                {
                    pConstLiteral = pConstLiteral->gtOp.gtOp1;
                }
#ifdef LEGACY_BACKEND

                if (pGetType->gtCall.gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC &&
                    info.compCompHnd->getIntrinsicID(pGetType->gtCall.gtCallMethHnd) == CORINFO_INTRINSIC_Object_GetType &&
#else
                if ((pGetType->gtOper == GT_INTRINSIC) && (pGetType->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Object_GetType) &&
#endif
                    pConstLiteral->gtOper == GT_CNS_INT &&
                    pConstLiteral->gtType == TYP_I_IMPL)
                {
                    CORINFO_CLASS_HANDLE clsHnd = CORINFO_CLASS_HANDLE(pConstLiteral->gtIntCon.gtCompileTimeHandle);

                    if (info.compCompHnd->canInlineTypeCheckWithObjectVTable(clsHnd))
                    {
                        // Method Table tree
#ifdef LEGACY_BACKEND
                        GenTreePtr objMT = gtNewOperNode(GT_IND, TYP_I_IMPL, pGetType->gtCall.gtCallObjp);
#else
                        GenTreePtr objMT = gtNewOperNode(GT_IND, TYP_I_IMPL, pGetType->gtUnOp.gtOp1);
#endif
                        objMT->gtFlags |= GTF_EXCEPT; // Null ref exception if object is null
                        compCurBB->bbFlags |= BBF_HAS_VTABREF;
                        optMethodFlags |= OMF_HAS_VTABLEREF;

                        // Method table constant
                        GenTreePtr cnsMT = pGetClassFromHandleArgument;

                        GenTreePtr compare = gtNewOperNode(oper, TYP_INT,
                                                           objMT,
                                                           cnsMT);

                        compare->gtFlags |= tree->gtFlags & (GTF_RELOP_JMP_USED | GTF_RELOP_QMARK | GTF_DONT_CSE);

                        // Morph and return
                        return fgMorphTree(compare);
                    }
                }
            }
        }
        fgMorphRecognizeBoxNullable(tree);
        op1 = tree->gtOp.gtOp1;
        op2 = tree->gtGetOp2();

        break;

#ifdef _TARGET_ARM_
    case GT_INTRINSIC:
        if (tree->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Round)
        {
            switch (tree->TypeGet())
            {
            case TYP_DOUBLE:
                return fgMorphIntoHelperCall(tree, CORINFO_HELP_DBLROUND, gtNewArgList(op1));
            case TYP_FLOAT:
                return fgMorphIntoHelperCall(tree, CORINFO_HELP_FLTROUND, gtNewArgList(op1));
            default:
                unreached();
            }
        }
        break;
#endif

    default:
        break;
    }

#if !CPU_HAS_FP_SUPPORT
    tree = fgMorphToEmulatedFP(tree);
#endif

    /* Could this operator throw an exception? */
    if  (fgGlobalMorph && tree->OperMayThrow())
    {
        if ((tree->OperGet() != GT_IND) || fgAddrCouldBeNull(tree->gtOp.gtOp1))
        {
            /* Mark the tree node as potentially throwing an exception */
            tree->gtFlags |= GTF_EXCEPT;
        }
    }

    /*-------------------------------------------------------------------------
     * Process the first operand, if any
     */

    if  (op1)
    {

#if LOCAL_ASSERTION_PROP
        // If we are entering the "then" part of a Qmark-Colon we must
        // save the state of the current copy assignment table
        // so that we can restore this state when entering the "else" part
        if (isQmarkColon)
        {
            noway_assert(optLocalAssertionProp);
            if (optAssertionCount)
            {
                noway_assert(optAssertionCount <= optMaxAssertionCount); // else ALLOCA() is a bad idea
                unsigned tabSize     = optAssertionCount * sizeof(AssertionDsc);
                origAssertionTab   = (AssertionDsc*) ALLOCA(tabSize);
                origAssertionCount = optAssertionCount;
                memcpy(origAssertionTab, optAssertionTabPrivate, tabSize);
            }
            else
            {
                origAssertionCount = 0;
                origAssertionTab   = NULL;
            }
        }
#endif // LOCAL_ASSERTION_PROP

        // We might need a new MorphAddressContext context.  (These are used to convey
        // parent context about how addresses being calculated will be used; see the
        // specification comment for MorphAddrContext for full details.)
        // Assume it's an Ind context to start.
        MorphAddrContext subIndMac1(MACK_Ind);
        MorphAddrContext* subMac1 = mac;
        if (subMac1 == NULL || subMac1->m_kind == MACK_Ind || subMac1->m_kind == MACK_CopyBlock)
        {
            switch (tree->gtOper)
            {
            case GT_ADDR:
                if (subMac1 == NULL)
                {
                    subMac1 = &subIndMac1;
                    subMac1->m_kind = MACK_Addr;
                }
                break;
            case GT_COMMA:
                // In a comma, the incoming context only applies to the rightmost arg of the
                // comma list.  The left arg (op1) gets a fresh context.
                subMac1 = NULL;
                break;
            case GT_COPYBLK:
            case GT_COPYOBJ:
                assert(subMac1 == NULL); // Should only occur at top level, since value is void.
                subMac1 = &s_CopyBlockMAC;
                break;
            case GT_LIST:
                // If the list is the first arg of a copy block, its two args should be evaluated as
                // IND-context addresses, separately.
                if (subMac1 != NULL && subMac1->m_kind == MACK_CopyBlock)
                {
                    subMac1 = &subIndMac1;
                }
                break;
            case GT_IND:
            case GT_INITBLK:
            case GT_OBJ:
                subMac1 = &subIndMac1;
                break;
            default:
                break;
            }
        }

        // For additions, if we're in an IND context keep track of whether
        // all offsets added to the address are constant, and their sum.
        if (tree->gtOper == GT_ADD && subMac1 != NULL)
        {
            assert(subMac1->m_kind == MACK_Ind || subMac1->m_kind == MACK_Addr); // Can't be a CopyBlock.
            GenTreePtr otherOp = tree->gtOp.gtOp2;
            // Is the other operator a constant?
            if (otherOp->IsCnsIntOrI())
            {
                ClrSafeInt<size_t> totalOffset(subMac1->m_totalOffset);
                totalOffset += otherOp->gtIntConCommon.IconValue();
                if (totalOffset.IsOverflow())
                {
                    // We will consider an offset so large as to overflow as "not a constant" --
                    // we will do a null check.
                    subMac1->m_allConstantOffsets = false;
                }
                else
                {
                    subMac1->m_totalOffset += otherOp->gtIntConCommon.IconValue();
                }
            }
            else
            {
                subMac1->m_allConstantOffsets = false;
            }
        }

        tree->gtOp.gtOp1 = op1 = fgMorphTree(op1, subMac1);

#if LOCAL_ASSERTION_PROP
        // If we are exiting the "then" part of a Qmark-Colon we must
        // save the state of the current copy assignment table
        // so that we can merge this state with the "else" part exit
        if (isQmarkColon)
        {
            noway_assert(optLocalAssertionProp);
            if (optAssertionCount)
            {
                noway_assert(optAssertionCount <= optMaxAssertionCount); // else ALLOCA() is a bad idea
                unsigned tabSize     = optAssertionCount * sizeof(AssertionDsc);
                thenAssertionTab   = (AssertionDsc*) ALLOCA(tabSize);
                thenAssertionCount = optAssertionCount;
                memcpy(thenAssertionTab, optAssertionTabPrivate, tabSize);
            }
            else
            {
                thenAssertionCount = 0;
                thenAssertionTab   = NULL;
            }
        }
#endif // LOCAL_ASSERTION_PROP

        /* Morphing along with folding and inlining may have changed the
         * side effect flags, so we have to reset them
         *
         * NOTE: Don't reset the exception flags on nodes that may throw */

        noway_assert(tree->gtOper != GT_CALL);

        if ((tree->gtOper != GT_INTRINSIC) || !IsIntrinsicImplementedByUserCall(tree->gtIntrinsic.gtIntrinsicId))
        {
            tree->gtFlags &= ~GTF_CALL;
        }

        if  (!tree->OperMayThrow())
            tree->gtFlags &= ~GTF_EXCEPT;

        /* Propagate the new flags */
        tree->gtFlags |= (op1->gtFlags & GTF_ALL_EFFECT);

        // &aliasedVar doesn't need GTF_GLOB_REF, though alisasedVar does
        // Similarly for clsVar
        if (oper == GT_ADDR && (op1->gtOper == GT_LCL_VAR || op1->gtOper == GT_CLS_VAR))
            tree->gtFlags &= ~GTF_GLOB_REF;
    } // if (op1)

    /*-------------------------------------------------------------------------
     * Process the second operand, if any
     */

    if  (op2)
    {

#if LOCAL_ASSERTION_PROP
        // If we are entering the "else" part of a Qmark-Colon we must
        // reset the state of the current copy assignment table
        if (isQmarkColon)
        {
            noway_assert(optLocalAssertionProp);
            optAssertionReset(0);
            if (origAssertionCount)
            {
                size_t tabSize    = origAssertionCount * sizeof(AssertionDsc);
                memcpy(optAssertionTabPrivate, origAssertionTab, tabSize);
                optAssertionReset(origAssertionCount);
            }
        }
#endif // LOCAL_ASSERTION_PROP

        // We might need a new MorphAddressContext context to use in evaluating op2.
        // (These are used to convey parent context about how addresses being calculated
        // will be used; see the specification comment for MorphAddrContext for full details.)
        // Assume it's an Ind context to start.
        MorphAddrContext subIndMac2(MACK_Ind);
        switch (tree->gtOper)
        {
        case GT_ADD:
            if (mac != NULL && mac->m_kind == MACK_Ind)
            {
                GenTreePtr otherOp = tree->gtOp.gtOp1;
                // Is the other operator a constant?
                if (otherOp->IsCnsIntOrI())
                {
                    mac->m_totalOffset += otherOp->gtIntConCommon.IconValue();
                }
                else
                {
                    mac->m_allConstantOffsets = false;
                }
            }
            break;
        case GT_LIST:
            if (mac != NULL && mac->m_kind == MACK_CopyBlock)
            {
                mac = &subIndMac2;
            }
            break;
        default:
            break;
        }
        tree->gtOp.gtOp2 = op2 = fgMorphTree(op2, mac);

        /* Propagate the side effect flags from op2 */

        tree->gtFlags |= (op2->gtFlags & GTF_ALL_EFFECT);

#if LOCAL_ASSERTION_PROP
        // If we are exiting the "else" part of a Qmark-Colon we must
        // merge the state of the current copy assignment table with
        // that of the exit of the "then" part.
        if (isQmarkColon)
        {
            noway_assert(optLocalAssertionProp);
            // If either exit table has zero entries then
            // the merged table also has zero entries
            if (optAssertionCount == 0 || thenAssertionCount == 0)
            {
                optAssertionReset(0);
            }
            else
            {
                size_t tabSize = optAssertionCount * sizeof(AssertionDsc);
                if ( (optAssertionCount != thenAssertionCount) ||
                     (memcmp(thenAssertionTab, optAssertionTabPrivate, tabSize) != 0) )
                {
                    // Yes they are different so we have to find the merged set
                    // Iterate over the copy asgn table removing any entries
                    // that do not have an exact match in the thenAssertionTab
                    AssertionIndex index = 1;
                    while (index <= optAssertionCount)
                    {
                        AssertionDsc* curAssertion = optGetAssertion(index);

                        for (unsigned j=0; j < thenAssertionCount; j++)
                        {
                            AssertionDsc* thenAssertion = &thenAssertionTab[j];

                            // Do the left sides match?
                            if ((curAssertion->op1.lcl.lclNum    == thenAssertion->op1.lcl.lclNum) &&
                                (curAssertion->assertionKind == thenAssertion->assertionKind))
                            {
                                // Do the right sides match?
                                if ((curAssertion->op2.kind    == thenAssertion->op2.kind) &&
                                    (curAssertion->op2.lconVal == thenAssertion->op2.lconVal))
                                {
                                    goto KEEP;
                                }
                                else
                                {
                                    goto REMOVE;
                                }
                            }
                        }
                        //
                        // If we fall out of the loop above then we didn't find
                        // any matching entry in the thenAssertionTab so it must
                        // have been killed on that path so we remove it here
                        //
                    REMOVE:
                        // The data at optAssertionTabPrivate[i] is to be removed
#ifdef DEBUG
                        if (verbose)
                        {
                            printf("The QMARK-COLON ");
                            printTreeID(tree);
                            printf(" removes assertion candidate #%d\n", index);
                        }
#endif
                        optAssertionRemove(index);
                        continue;
                    KEEP:
                        // The data at optAssertionTabPrivate[i] is to be kept
                        index++;
                    }
                }
            }
        }
#endif // LOCAL_ASSERTION_PROP
    } // if (op2)

DONE_MORPHING_CHILDREN:

    /*-------------------------------------------------------------------------
     * Now do POST-ORDER processing
     */

#if FEATURE_FIXED_OUT_ARGS && !defined(_TARGET_64BIT_)
    // Variable shifts of a long end up being helper calls, so mark the tree as such. This
    // is potentially too conservative, since they'll get treated as having side effects.
    // It is important to mark them as calls so if they are part of an argument list,
    // they will get sorted and processed properly (for example, it is important to handle
    // all nested calls before putting struct arguments in the argument registers). We
    // could mark the trees just before argument processing, but it would require a full
    // tree walk of the argument tree, so we just do it here, instead, even though we'll
    // mark non-argument trees (that will still get converted to calls, anyway).
    if (GenTree::OperIsShift(oper) &&
        (tree->TypeGet() == TYP_LONG) &&
        (op2->OperGet() != GT_CNS_INT))
    {
        tree->gtFlags |= GTF_CALL;
    }
#endif // FEATURE_FIXED_OUT_ARGS && !_TARGET_64BIT_

    if (varTypeIsGC(tree->TypeGet()) && (op1 && !varTypeIsGC(op1->TypeGet()))
                                     && (op2 && !varTypeIsGC(op2->TypeGet())))
    {
        // The tree is really not GC but was marked as such. Now that the
        // children have been unmarked, unmark the tree too.

        // Remember that GT_COMMA inherits it's type only from op2
        if (tree->gtOper == GT_COMMA)
            tree->gtType = genActualType(op2->TypeGet());
        else
            tree->gtType = genActualType(op1->TypeGet());
    }

    GenTreePtr oldTree = tree;

    GenTreePtr qmarkOp1 = NULL;
    GenTreePtr qmarkOp2 = NULL;

    if ((tree->OperGet() == GT_QMARK) &&
        (tree->gtOp.gtOp2->OperGet() == GT_COLON))
    {
        qmarkOp1 = oldTree->gtOp.gtOp2->gtOp.gtOp1;
        qmarkOp2 = oldTree->gtOp.gtOp2->gtOp.gtOp2;
    }

    // Try to fold it, maybe we get lucky,
    tree = gtFoldExpr(tree);

    if (oldTree != tree)
    {
        /* if gtFoldExpr returned op1 or op2 then we are done */
        if ((tree == op1) || (tree == op2) || (tree == qmarkOp1) || (tree == qmarkOp2))
            return tree;

        /* If we created a comma-throw tree then we need to morph op1 */
        if (fgIsCommaThrow(tree))
        {
            tree->gtOp.gtOp1 = fgMorphTree(tree->gtOp.gtOp1);
            fgMorphTreeDone(tree);
            return tree;
        }

        return tree;
    }
    else if (tree->OperKind() & GTK_CONST)
    {
        return tree;
    }

    /* gtFoldExpr could have used setOper to change the oper */
    oper    = tree->OperGet();
    typ     = tree->TypeGet();

    /* gtFoldExpr could have changed op1 and op2 */
    op1  = tree->gtOp.gtOp1;
    op2  = tree->gtGetOp2();

    // Do we have an integer compare operation?
    //
    if (tree->OperIsCompare() && varTypeIsIntegralOrI(tree->TypeGet()))
    {
        // Are we comparing against zero?
        //
        if (op2->IsZero())
        {
            // Request that the codegen for op1 sets the condition flags
            // when it generates the code for op1.
            //
            // Codegen for op1 must set the condition flags if
            // this method returns true.
            //
            op1->gtRequestSetFlags();
        }
    }
    /*-------------------------------------------------------------------------
     * Perform the required oper-specific postorder morphing
     */

    GenTreePtr      temp;
    GenTreePtr      cns1, cns2;
    GenTreePtr      thenNode;
    GenTreePtr      elseNode;
    size_t          ival1, ival2;
    GenTreePtr      lclVarTree;
    GenTreeLclVarCommon* lclVarCmnTree;
    FieldSeqNode*   fieldSeq = NULL;

    switch (oper)
    {
    case GT_ASG:
        
        lclVarTree = fgIsIndirOfAddrOfLocal(op1);
        if (lclVarTree != NULL)
        {
            lclVarTree->gtFlags |= GTF_VAR_DEF;
        }

        /* If we are storing a small type, we might be able to omit a cast */
        if ((op1->gtOper == GT_IND) && varTypeIsSmall(op1->TypeGet()))
        {
            if (!gtIsActiveCSE_Candidate(op2) && (op2->gtOper == GT_CAST) &&  !op2->gtOverflow())
            {
                var_types   castType = op2->CastToType();

                // If we are performing a narrowing cast and
                // castType is larger or the same as op1's type
                // then we can discard the cast.

                if  (varTypeIsSmall(castType) && (castType >= op1->TypeGet()))
                {
                    tree->gtOp.gtOp2 = op2 = op2->gtCast.CastOp();
                }
            }
            else if (op2->OperIsCompare() && varTypeIsByte(op1->TypeGet()))
            {
                /* We don't need to zero extend the setcc instruction */
                op2->gtType = TYP_BYTE;
            }
        }
        // If we introduced a CSE we may need to undo the optimization above
        // (i.e. " op2->gtType = TYP_BYTE;" which depends upon op1 being a GT_IND of a byte type)
        // When we introduce the CSE we remove the GT_IND and subsitute a GT_LCL_VAR in it place.
        else if (op2->OperIsCompare() && (op2->gtType == TYP_BYTE) && (op1->gtOper == GT_LCL_VAR))
        {
            unsigned    varNum = op1->gtLclVarCommon.gtLclNum;
            LclVarDsc * varDsc = &lvaTable[varNum];

            /* We again need to zero extend the setcc instruction */
            op2->gtType = varDsc->TypeGet();
        }

        __fallthrough;

    case GT_COPYOBJ:
    case GT_COPYBLK:
    case GT_INITBLK:
        fgAssignSetVarDef(tree);

        __fallthrough;

    case GT_ASG_ADD:
    case GT_ASG_SUB:
    case GT_ASG_MUL:
    case GT_ASG_DIV:
    case GT_ASG_MOD:
    case GT_ASG_UDIV:
    case GT_ASG_UMOD:
    case GT_ASG_OR:
    case GT_ASG_XOR:
    case GT_ASG_AND:
    case GT_ASG_LSH:
    case GT_ASG_RSH:
    case GT_ASG_RSZ:

        /* We can't CSE the LHS of an assignment */
        /* We also must set in the pre-morphing phase, otherwise assertionProp doesn't see it */
        op1->gtFlags |= GTF_DONT_CSE;
        break;

    case GT_EQ:
    case GT_NE:

        /* Make sure we're allowed to do this */

        if (optValnumCSE_phase)
        {
            // It is not safe to reorder/delete CSE's
            break;
        }

        cns2 = op2;

        /* Check for "(expr +/- icon1) ==/!= (non-zero-icon2)" */

        if  (cns2->gtOper == GT_CNS_INT && cns2->gtIntCon.gtIconVal != 0)
        {
            op1 = tree->gtOp.gtOp1;

            /* Since this can occur repeatedly we use a while loop */

            while ((op1->gtOper == GT_ADD || op1->gtOper == GT_SUB) &&
                   (op1->gtOp.gtOp2->gtOper == GT_CNS_INT)          &&
                   (op1->gtType             == TYP_INT)             &&
                   (op1->gtOverflow()       == false))
            {
                /* Got it; change "x+icon1==icon2" to "x==icon2-icon1" */

                ival1 = op1->gtOp.gtOp2->gtIntCon.gtIconVal;
                ival2 = cns2->gtIntCon.gtIconVal;

                if  (op1->gtOper == GT_ADD)
                {
                    ival2 -= ival1;
                }
                else
                {
                    ival2 += ival1;
                }
                cns2->gtIntCon.gtIconVal = ival2;

#ifdef _TARGET_64BIT_
                // we need to properly re-sign-extend or truncate as needed.
                cns2->AsIntCon()->TruncateOrSignExtend32();
#endif // _TARGET_64BIT_                

                op1 = tree->gtOp.gtOp1 = op1->gtOp.gtOp1;
            }
        }

        //
        // Here we look for the following tree
        //
        //                        EQ/NE
        //                        /  \
        //                      op1   CNS 0/1
        //
        ival2 = INT_MAX;  // The value of INT_MAX for ival2 just means that the constant value is not 0 or 1

        // cast to unsigned allows test for both 0 and 1
        if ((cns2->gtOper == GT_CNS_INT) && (((size_t) cns2->gtIntConCommon.IconValue()) <= 1U))
        {
            ival2 = (size_t) cns2->gtIntConCommon.IconValue();
        }
        else // cast to UINT64 allows test for both 0 and 1
        if ((cns2->gtOper == GT_CNS_LNG) && (((UINT64) cns2->gtIntConCommon.LngValue()) <= 1ULL))
        {
            ival2 = (size_t) cns2->gtIntConCommon.LngValue();
        }

        if (ival2 != INT_MAX)
        {
            // If we don't have a comma and relop, we can't do this optimization
            //
            if ((op1->gtOper == GT_COMMA) && (op1->gtOp.gtOp2->OperIsCompare()))
            {
                // Here we look for the following transformation
                //
                //                  EQ/NE                    Possible REVERSE(RELOP)
                //                  /  \                           /      \
                //               COMMA CNS 0/1             ->   COMMA   relop_op2
                //              /   \                          /    \
                //             x  RELOP                       x     relop_op1
                //               /    \
                //         relop_op1  relop_op2
                //
                //
                //
                GenTreePtr comma = op1;
                GenTreePtr relop = comma->gtOp.gtOp2;

                GenTreePtr relop_op1 = relop->gtOp.gtOp1;

                bool reverse = ((ival2 == 0) == (oper == GT_EQ));

                if (reverse)
                {
                    gtReverseCond(relop);
                }

                relop->gtOp.gtOp1 = comma;
                comma->gtOp.gtOp2 = relop_op1;

                // Comma now has fewer nodes underneath it, so we need to regenerate its flags
                comma->gtFlags &= ~GTF_ALL_EFFECT;
                comma->gtFlags |= (comma->gtOp.gtOp1->gtFlags) & GTF_ALL_EFFECT;
                comma->gtFlags |= (comma->gtOp.gtOp2->gtFlags) & GTF_ALL_EFFECT;

                noway_assert((relop->gtFlags & GTF_RELOP_JMP_USED) == 0);
                noway_assert((relop->gtFlags & GTF_REVERSE_OPS)    == 0);
                relop->gtFlags |= tree->gtFlags & (GTF_RELOP_JMP_USED|GTF_RELOP_QMARK|GTF_DONT_CSE|GTF_ALL_EFFECT);

                return relop;
            }

            if (op1->gtOper == GT_COMMA)
            {
                // Here we look for the following tree
                // and when the LCL_VAR is a temp we can fold the tree:
                //
                //                        EQ/NE                  EQ/NE
                //                        /  \                   /  \
                //                     COMMA  CNS 0/1  ->     RELOP CNS 0/1
                //                     /   \                   / \
                //                   ASG  LCL_VAR
                //                  /  \
                //           LCL_VAR   RELOP
                //                      / \
                //

                GenTreePtr  asg = op1->gtOp.gtOp1;
                GenTreePtr  lcl = op1->gtOp.gtOp2;

                /* Make sure that the left side of the comma is the assignment of the LCL_VAR */
                if (asg->gtOper != GT_ASG)
                    goto SKIP;

                /* The right side of the comma must be a LCL_VAR temp */
                if (lcl->gtOper != GT_LCL_VAR)
                    goto SKIP;

                unsigned lclNum = lcl->gtLclVarCommon.gtLclNum;   noway_assert(lclNum < lvaCount);

                /* If the LCL_VAR is not a temp then bail, a temp has a single def */
                if (!lvaTable[lclNum].lvIsTemp)
                    goto SKIP;

#if FEATURE_ANYCSE
                /* If the LCL_VAR is a CSE temp then bail, it could have multiple defs/uses */
                // Fix 383856 X86/ARM ILGEN
                if (lclNumIsCSE(lclNum))
                    goto SKIP;
#endif

                /* We also must be assigning the result of a RELOP */
                if (asg->gtOp.gtOp1->gtOper != GT_LCL_VAR)
                    goto SKIP;

                /* Both of the LCL_VAR must match */
                if (asg->gtOp.gtOp1->gtLclVarCommon.gtLclNum != lclNum)
                    goto SKIP;

                /* If right side of asg is not a RELOP then skip */
                if (!asg->gtOp.gtOp2->OperIsCompare())
                    goto SKIP;

                LclVarDsc * varDsc = lvaTable + lclNum;

                /* Set op1 to the right side of asg, (i.e. the RELOP) */
                op1 = asg->gtOp.gtOp2;

                DEBUG_DESTROY_NODE(asg->gtOp.gtOp1);
                DEBUG_DESTROY_NODE(lcl);

                /* This local variable should never be used again */
                // <BUGNUM>
                // VSW 184221: Make RefCnt to zero to indicate that this local var
                // is not used any more. (Keey the lvType as is.)
                // Otherwise lvOnFrame will be set to true in Compiler::raMarkStkVars
                // And then emitter::emitEndCodeGen will assert in the following line:
                //        noway_assert( dsc->lvTracked);
                // </BUGNUM>
                noway_assert(varDsc->lvRefCnt == 0  ||  // lvRefCnt may not have been set yet.
                             varDsc->lvRefCnt == 2      // Or, we assume this tmp should only be used here,
                                                        // and it only shows up twice.
                      );
                lvaTable[lclNum].lvRefCnt = 0;
                lvaTable[lclNum].lvaResetSortAgainFlag(this);
            }


            if (op1->OperIsCompare())
            {
                // Here we look for the following tree
                //
                //                        EQ/NE           ->      RELOP/!RELOP
                //                        /  \                       /    \
                //                     RELOP  CNS 0/1
                //                     /   \
                //
                // Note that we will remove/destroy the EQ/NE node and move 
                // the RELOP up into it's location.

                /* Here we reverse the RELOP if necessary */

                bool reverse = ((ival2 == 0) == (oper == GT_EQ));

                if (reverse)
                {
                    gtReverseCond(op1);
                }

                /* Propagate gtType of tree into op1 in case it is TYP_BYTE for setcc optimization */
                op1->gtType = tree->gtType;

                noway_assert((op1->gtFlags & GTF_RELOP_JMP_USED) == 0);
                op1->gtFlags |= tree->gtFlags & (GTF_RELOP_JMP_USED|GTF_RELOP_QMARK|GTF_DONT_CSE);

                DEBUG_DESTROY_NODE(tree);
                return op1;

            }

            //
            // Now we check for a compare with the result of an '&' operator
            //
            // Here we look for the following transformation:
            //
            //                        EQ/NE                  EQ/NE
            //                        /  \                   /  \
            //                      AND   CNS 0/1  ->      AND   CNS 0
            //                     /   \                  /   \
            //                RSZ/RSH   CNS 1            x     CNS (1 << y)
            //                  /  \
            //                 x   CNS_INT +y

            if (op1->gtOper == GT_AND)
            {
                GenTreePtr andOp    = op1;
                GenTreePtr rshiftOp = andOp->gtOp.gtOp1;

                if ((rshiftOp->gtOper != GT_RSZ) && (rshiftOp->gtOper != GT_RSH))
                    goto SKIP;

                if (!rshiftOp->gtOp.gtOp2->IsCnsIntOrI())
                    goto SKIP;

                ssize_t shiftAmount = rshiftOp->gtOp.gtOp2->gtIntCon.gtIconVal;

                if (shiftAmount < 0)
                    goto SKIP;

                if (andOp->gtType == TYP_INT)
                {
                    if (!andOp->gtOp.gtOp2->IsCnsIntOrI())
                        goto SKIP;

                    if (andOp->gtOp.gtOp2->gtIntCon.gtIconVal != 1)
                        goto SKIP;

                    if (shiftAmount > 31)
                        goto SKIP;

                    UINT32 newAndOperand = ((UINT32) 1) << shiftAmount;

                    andOp->gtOp.gtOp2->gtIntCon.gtIconVal = newAndOperand;

                    // Reverse the cond if necessary
                    if (ival2 == 1)
                    {
                        gtReverseCond(tree);
                        cns2->gtIntCon.gtIconVal = 0;
                        oper = tree->gtOper;
                    }

                }
                else if (andOp->gtType == TYP_LONG)
                {
                    if (andOp->gtOp.gtOp2->gtOper != GT_CNS_NATIVELONG)
                        goto SKIP;

                    if (andOp->gtOp.gtOp2->gtIntConCommon.LngValue() != 1)
                        goto SKIP;

                    if (shiftAmount > 63)
                        goto SKIP;

                    UINT64 newAndOperand = ((UINT64) 1) << shiftAmount;

                    andOp->gtOp.gtOp2->gtIntConCommon.SetLngValue(newAndOperand);

                    // Reverse the cond if necessary
                    if (ival2 == 1)
                    {
                        gtReverseCond(tree);
                        cns2->gtIntConCommon.SetLngValue(0);
                        oper = tree->gtOper;
                    }
                }

                andOp->gtOp.gtOp1 = rshiftOp->gtOp.gtOp1;

                DEBUG_DESTROY_NODE(rshiftOp->gtOp.gtOp2);
                DEBUG_DESTROY_NODE(rshiftOp);
            }
        } // END if (ival2 != INT_MAX)

SKIP:
        /* Now check for compares with small constant longs that can be cast to int */

        if (!cns2->OperIsConst())
            goto COMPARE;

        if (cns2->TypeGet() != TYP_LONG)
            goto COMPARE;

        /* Is the constant 31 bits or smaller? */

        if ((cns2->gtIntConCommon.LngValue() >> 31) != 0)
            goto COMPARE;

        /* Is the first comparand mask operation of type long ? */

        if  (op1->gtOper != GT_AND)
        {
            /* Another interesting case: cast from int */

            if  (op1->gtOper         == GT_CAST &&
                 op1->CastFromType() == TYP_INT &&
                 !gtIsActiveCSE_Candidate(op1)  &&  // op1 cannot be a CSE candidate
                 !op1->gtOverflow())                // cannot be an overflow checking cast
            {
                /* Simply make this into an integer comparison */

                tree->gtOp.gtOp1 = op1->gtCast.CastOp();
                tree->gtOp.gtOp2 = gtNewIconNode((int)cns2->gtIntConCommon.LngValue(), TYP_INT);
            }

            goto COMPARE;
        }

        noway_assert(op1->TypeGet() == TYP_LONG && op1->OperGet() == GT_AND);

        /* Is the result of the mask effectively an INT ? */

        GenTreePtr andMask; andMask = op1->gtOp.gtOp2;
        if  (andMask->gtOper != GT_CNS_NATIVELONG)
            goto COMPARE;
        if  ((andMask->gtIntConCommon.LngValue() >> 32) != 0)
            goto COMPARE;

        /* Now we know that we can cast gtOp.gtOp1 of AND to int */

        op1->gtOp.gtOp1 = gtNewCastNode(TYP_INT,
                                         op1->gtOp.gtOp1,
                                         TYP_INT);

        /* now replace the mask node (gtOp.gtOp2 of AND node) */

        noway_assert(andMask == op1->gtOp.gtOp2);

        ival1 = (int) andMask->gtIntConCommon.LngValue();
        andMask->SetOper(GT_CNS_INT);
        andMask->gtType             = TYP_INT;
        andMask->gtIntCon.gtIconVal = ival1;

        /* now change the type of the AND node */

        op1->gtType = TYP_INT;

        /* finally we replace the comparand */

        ival2 = (int) cns2->gtIntConCommon.LngValue();
        cns2->SetOper(GT_CNS_INT);
        cns2->gtType = TYP_INT;

        noway_assert(cns2 == op2);
        cns2->gtIntCon.gtIconVal = ival2;

        goto COMPARE;

    case GT_LT:
    case GT_LE:
    case GT_GE:
    case GT_GT:
 
        if ((tree->gtFlags & GTF_UNSIGNED) == 0)
        {
            if (op2->gtOper == GT_CNS_INT)
            {
                cns2 = op2;
                /* Check for "expr relop 1" */
                if (cns2->gtIntCon.gtIconVal == +1)
                {
                    /* Check for "expr >= 1" */
                    if (oper == GT_GE)
                    {
                        /* Change to "expr > 0" */
                        oper = GT_GT;
                        goto SET_OPER;
                    }
                    /* Check for "expr < 1" */
                    else if (oper == GT_LT)
                    {
                        /* Change to "expr <= 0" */
                        oper = GT_LE;
                        goto SET_OPER;
                    }
                }
                /* Check for "expr relop -1" */
                else if ((cns2->gtIntCon.gtIconVal == -1) && ((oper == GT_LE) || (oper == GT_GT)))
                {
                    /* Check for "expr <= -1" */
                    if (oper == GT_LE)
                    {
                        /* Change to "expr < 0" */
                        oper = GT_LT;
                        goto SET_OPER;
                    }
                    /* Check for "expr > -1" */
                    else if (oper == GT_GT)
                    {
                        /* Change to "expr >= 0" */
                        oper = GT_GE;

SET_OPER:
                        // IF we get here we should be changing 'oper' 
                        assert(tree->OperGet() != oper);

                        // Keep the old ValueNumber for 'tree' as the new expr
                        // will still compute the same value as before
                        tree->SetOper(oper, GenTree::PRESERVE_VN);
                        cns2->gtIntCon.gtIconVal = 0;

                        // vnStore is null before the ValueNumber phase has run
                        if (vnStore != nullptr)
                        {
                            // Update the ValueNumber for 'cns2', as we just changed it to 0
                            fgValueNumberTreeConst(cns2);
                        }
                     
                        op2 = tree->gtOp.gtOp2 = gtFoldExpr(op2);
                    }
                }
            }
        }

COMPARE:

        noway_assert(tree->OperKind() & GTK_RELOP);

        /* Check if the result of the comparison is used for a jump.
         * If not then only the int (i.e. 32 bit) case is handled in
         * the code generator through the (x86) "set" instructions.
         * For the rest of the cases, the simplest way is to
         * "simulate" the comparison with ?:
         *
         * On ARM, we previously used the IT instruction, but the IT instructions
         * have mostly been declared obsolete and off-limits, so all cases on ARM
         * get converted to ?: */

        if (!(tree->gtFlags & GTF_RELOP_JMP_USED) &&
            fgMorphRelopToQmark(op1))
        {
            /* We convert it to "(CMP_TRUE) ? (1):(0)" */

            op1  = tree;
            op1->gtFlags |= (GTF_RELOP_JMP_USED | GTF_RELOP_QMARK | GTF_DONT_CSE);
            op1->gtRequestSetFlags();

            op2  = new (this, GT_COLON) GenTreeColon(TYP_INT, gtNewIconNode(1), gtNewIconNode(0)
                                                     );
            op2  = fgMorphTree(op2);

            tree = gtNewQmarkNode(TYP_INT, op1, op2);

            fgMorphTreeDone(tree);

            return tree;
        }
        break;

   case GT_QMARK:

        /* If op1 is a comma throw node then we won't be keeping op2 */
        if (fgIsCommaThrow(op1))
            break;

        /* Get hold of the two branches */

        noway_assert(op2->OperGet() == GT_COLON);
        elseNode = op2->AsColon()->ElseNode();
        thenNode = op2->AsColon()->ThenNode();

        /* Try to hoist assignments out of qmark colon constructs.
           ie. replace (cond?(x=a):(x=b)) with (x=(cond?a:b)). */

        if (tree->TypeGet() == TYP_VOID &&
            thenNode->OperGet() == GT_ASG &&
            elseNode->OperGet() == GT_ASG &&
            thenNode->TypeGet() != TYP_LONG &&
            GenTree::Compare(thenNode->gtOp.gtOp1, elseNode->gtOp.gtOp1) &&
            thenNode->gtOp.gtOp2->TypeGet() == elseNode->gtOp.gtOp2->TypeGet())
        {
                noway_assert(thenNode->TypeGet() == elseNode->TypeGet());

                GenTreePtr asg = thenNode;
                GenTreePtr colon = op2;
                colon->gtOp.gtOp1 = thenNode->gtOp.gtOp2;
                colon->gtOp.gtOp2 = elseNode->gtOp.gtOp2;
                tree->gtType = colon->gtType = asg->gtOp.gtOp2->gtType;
                asg->gtOp.gtOp2 = tree;

                // Asg will have all the flags that the QMARK had
                asg->gtFlags       |= (tree->gtFlags & GTF_ALL_EFFECT);

                // Colon flag won't have the flags that x had.
                colon->gtFlags &= ~GTF_ALL_EFFECT;
                colon->gtFlags |= (colon->gtOp.gtOp1->gtFlags |
                                   colon->gtOp.gtOp2->gtFlags) & GTF_ALL_EFFECT;

                DEBUG_DESTROY_NODE(elseNode->gtOp.gtOp1);
                DEBUG_DESTROY_NODE(elseNode);

                return asg;
        }


        /* If the 'else' branch is empty swap the two branches and reverse the condition */

        if (elseNode->IsNothingNode())
        {
            /* This can only happen for VOID ?: */
            noway_assert(op2->gtType == TYP_VOID);

            /* If the thenNode and elseNode are both nop nodes then optimize away the QMARK */
            if (thenNode->IsNothingNode())
            {
                // We may be able to throw away op1 (unless it has side-effects)

                if ((op1->gtFlags & GTF_SIDE_EFFECT) == 0)
                {
                    /* Just return a a Nop Node */
                    return thenNode;
                }
                else
                {
                    /* Just return the relop, but clear the special flags.  Note
                       that we can't do that for longs and floats (see code under
                       COMPARE label above) */

                    if (!fgMorphRelopToQmark(op1->gtOp.gtOp1))
                    {
                        op1->gtFlags &= ~(GTF_RELOP_QMARK | GTF_RELOP_JMP_USED);
                        return op1;
                    }
                }
            }
            else
            {
                GenTreePtr tmp = elseNode;

                op2->AsColon()->ElseNode() = elseNode = thenNode;
                op2->AsColon()->ThenNode() = thenNode = tmp;
                gtReverseCond(op1);
            }
        }

#if !defined(_TARGET_ARM_)
        // If we have (cond)?0:1, then we just return "cond" for TYP_INTs
        //
        // Don't do this optimization for ARM: we always require assignment
        // to boolean to remain ?:, since we don't have any way to generate
        // this with straight-line code, like x86 does using setcc (at least
        // after the IT instruction is deprecated).

        if (genActualType(op1->gtOp.gtOp1->gtType) == TYP_INT    &&
            genActualType(typ)                     == TYP_INT    &&
            thenNode->gtOper                       == GT_CNS_INT &&
            elseNode->gtOper                       == GT_CNS_INT)
        {
            ival1 = thenNode->gtIntCon.gtIconVal;
            ival2 = elseNode->gtIntCon.gtIconVal;

            // Is one constant 0 and the other 1?
            if ((ival1 | ival2) == 1 && (ival1 & ival2) == 0)
            {
                // If the constants are {1, 0}, reverse the condition
                if (ival1 == 1)
                    gtReverseCond(op1);

                // Unmark GTF_RELOP_JMP_USED on the condition node so it knows that it
                // needs to materialize the result as a 0 or 1.
                noway_assert(op1->gtFlags & (GTF_RELOP_QMARK | GTF_RELOP_JMP_USED));
                op1->gtFlags &= ~(GTF_RELOP_QMARK | GTF_RELOP_JMP_USED);

                DEBUG_DESTROY_NODE(tree);
                DEBUG_DESTROY_NODE(op2);

                return op1;
            }
        }
#endif // !_TARGET_ARM_

        break; // end case GT_QMARK


    case GT_MUL:

#ifndef _TARGET_64BIT_
#if!LONG_MATH_REGPARAM
        if (typ == TYP_LONG)
        {
            // This must be GTF_MUL_64RSLT
            assert(tree->gtIsValid64RsltMul());
            return tree;
        }
#endif
#endif // _TARGET_64BIT_
        goto CM_OVF_OP;

    case GT_SUB:

        if (tree->gtOverflow())
            goto CM_OVF_OP;

        /* Check for "op1 - cns2" , we change it to "op1 + (-cns2)" */

        noway_assert(op2);
        if  (op2->IsCnsIntOrI())
        {
            /* Negate the constant and change the node to be "+" */

            op2->gtIntConCommon.SetIconValue(-op2->gtIntConCommon.IconValue());
            oper = GT_ADD;
            tree->ChangeOper(oper);
            goto CM_ADD_OP;
        }

        /* Check for "cns1 - op2" , we change it to "(cns1 + (-op2))" */

        noway_assert(op1);
        if  (op1->IsCnsIntOrI())
        {
            noway_assert(varTypeIsIntOrI(tree));

            tree->gtOp.gtOp2 = op2 = gtNewOperNode(GT_NEG, tree->gtType, op2); // The type of the new GT_NEG node should be the same
                                                                               // as the type of the tree, i.e. tree->gtType.
            fgMorphTreeDone(op2);

            oper = GT_ADD;
            tree->ChangeOper(oper);
            goto CM_ADD_OP;
        }

        /* No match - exit */

        break;

#ifdef _TARGET_ARM64_
    case GT_DIV:
        if (!varTypeIsFloating(tree->gtType))
        {
            // Codegen for this instruction needs to be able to throw two exceptions:
            fgAddCodeRef(compCurBB, bbThrowIndex(compCurBB), SCK_OVERFLOW, fgPtrArgCntCur);
            fgAddCodeRef(compCurBB, bbThrowIndex(compCurBB), SCK_DIV_BY_ZERO, fgPtrArgCntCur);
        }
        break;
    case GT_UDIV:
        // Codegen for this instruction needs to be able to throw one exception:
        fgAddCodeRef(compCurBB, bbThrowIndex(compCurBB), SCK_DIV_BY_ZERO, fgPtrArgCntCur);
        break;
#endif

    case GT_ADD:

CM_OVF_OP :
        if (tree->gtOverflow())
        {
            tree->gtRequestSetFlags();

            // Add the excptn-throwing basic block to jump to on overflow

            fgAddCodeRef(compCurBB, bbThrowIndex(compCurBB), SCK_OVERFLOW, fgPtrArgCntCur);

            // We can't do any commutative morphing for overflow instructions

            break;
        }

CM_ADD_OP:

    case GT_OR:
    case GT_XOR:
    case GT_AND:

        /* Commute any non-REF constants to the right */

        noway_assert(op1);
        if  (op1->OperIsConst() && (op1->gtType != TYP_REF))
        {
            // TODO-Review: We used to assert here that
            // noway_assert(!op2->OperIsConst() || !opts.OptEnabled(CLFLG_CONSTANTFOLD));
            // With modifications to AddrTaken==>AddrExposed, we did more assertion propagation,
            // and would sometimes hit this assertion.  This may indicate a missed "remorph".
            // Task is to re-enable this assertion and investigate.

            /* Swap the operands */
            tree->gtOp.gtOp1 = op2;
            tree->gtOp.gtOp2 = op1;

            op1 = op2;
            op2 = tree->gtOp.gtOp2;
        }

        /* See if we can fold GT_ADD nodes. */

        if (oper == GT_ADD)
        {
            /* Fold "((x+icon1)+(y+icon2)) to ((x+y)+(icon1+icon2))" */

            if (op1->gtOper             == GT_ADD     &&
                op2->gtOper             == GT_ADD     &&
                !gtIsActiveCSE_Candidate(op2)         &&
                op1->gtOp.gtOp2->gtOper == GT_CNS_INT &&
                op2->gtOp.gtOp2->gtOper == GT_CNS_INT &&
                !op1->gtOverflow()                    &&
                !op2->gtOverflow()                       )
            {
                cns1 = op1->gtOp.gtOp2;
                cns2 = op2->gtOp.gtOp2;
                cns1->gtIntCon.gtIconVal += cns2->gtIntCon.gtIconVal;
#ifdef _TARGET_64BIT_
                if (cns1->TypeGet() == TYP_INT)
                {
                    // we need to properly re-sign-extend or truncate after adding two int constants above
                    cns1->AsIntCon()->TruncateOrSignExtend32();
                }
#endif //_TARGET_64BIT_

                tree->gtOp.gtOp2    = cns1;
                DEBUG_DESTROY_NODE(cns2);

                op1->gtOp.gtOp2     = op2->gtOp.gtOp1;
                op1->gtFlags       |= (op1->gtOp.gtOp2->gtFlags & GTF_ALL_EFFECT);
                DEBUG_DESTROY_NODE(op2);
                op2 = tree->gtOp.gtOp2;
            }

            if (op2->IsCnsIntOrI() && varTypeIsIntegralOrI(typ))
            {
                /* Fold "((x+icon1)+icon2) to (x+(icon1+icon2))" */

                if (op1->gtOper == GT_ADD          &&
                    !gtIsActiveCSE_Candidate(op1)  &&
                    op1->gtOp.gtOp2->IsCnsIntOrI() &&
                    !op1->gtOverflow()             &&
                    op1->gtOp.gtOp2->OperGet() == op2->OperGet())
                {
                    cns1 = op1->gtOp.gtOp2;
                    op2->gtIntConCommon.SetIconValue(cns1->gtIntConCommon.IconValue() + op2->gtIntConCommon.IconValue());  
#ifdef _TARGET_64BIT_
                    if (op2->TypeGet() == TYP_INT)
                    {
                        // we need to properly re-sign-extend or truncate after adding two int constants above
                        op2->AsIntCon()->TruncateOrSignExtend32();
                    }
#endif //_TARGET_64BIT_

                    if (cns1->OperGet() == GT_CNS_INT)
                    {
                        op2->gtIntCon.gtFieldSeq = 
                            GetFieldSeqStore()->Append(cns1->gtIntCon.gtFieldSeq,
                                                       op2->gtIntCon.gtFieldSeq);
                    }
                    DEBUG_DESTROY_NODE(cns1);

                    tree->gtOp.gtOp1 = op1->gtOp.gtOp1;
                    DEBUG_DESTROY_NODE(op1);
                    op1 = tree->gtOp.gtOp1;
                }

                // Fold (x + 0).

                if ((op2->gtIntConCommon.IconValue() == 0) && !gtIsActiveCSE_Candidate(tree))
                {

                    // If this addition is adding an offset to a null pointer,
                    // avoid the work and yield the null pointer immediately.
                    // Dereferencing the pointer in either case will have the
                    // same effect.

                    if (!gtIsActiveCSE_Candidate(op1) && varTypeIsGC(op2->TypeGet()))
                    {
                        op2->gtType = tree->gtType;
                        DEBUG_DESTROY_NODE(op1);
                        DEBUG_DESTROY_NODE(tree);
                        return op2;
                    }

                    // Remove the addition iff it won't change the tree type
                    // to TYP_REF.

                    if (!gtIsActiveCSE_Candidate(op2) && 
                        ((op1->TypeGet() == tree->TypeGet()) ||
                        (op1->TypeGet() != TYP_REF)))
                    {
                        if (fgGlobalMorph &&
                            (op2->OperGet() == GT_CNS_INT)      &&
                            (op2->gtIntCon.gtFieldSeq != NULL)  &&
                            (op2->gtIntCon.gtFieldSeq != FieldSeqStore::NotAField()))
                        {
                            fgAddFieldSeqForZeroOffset(op1, op2->gtIntCon.gtFieldSeq);
                        }

                        DEBUG_DESTROY_NODE(op2);
                        DEBUG_DESTROY_NODE(tree);

                        return op1;
                    }
                }
            }
        }
             /* See if we can fold GT_MUL by const nodes */
        else if (oper == GT_MUL && op2->IsCnsIntOrI() && !optValnumCSE_phase)
        {
#ifndef _TARGET_64BIT_
            noway_assert(typ <= TYP_UINT);
#endif // _TARGET_64BIT_
            noway_assert(!tree->gtOverflow());

            ssize_t mult = op2->gtIntConCommon.IconValue();
            bool op2IsConstIndex = op2->OperGet() == GT_CNS_INT &&
                                   op2->gtIntCon.gtFieldSeq != nullptr &&
                                   op2->gtIntCon.gtFieldSeq->IsConstantIndexFieldSeq();

            assert(!op2IsConstIndex || op2->AsIntCon()->gtFieldSeq->m_next == nullptr);

            if (mult == 0)
            {
                // We may be able to throw away op1 (unless it has side-effects)

                if ((op1->gtFlags & GTF_SIDE_EFFECT) == 0)
                {
                    DEBUG_DESTROY_NODE(op1);
                    DEBUG_DESTROY_NODE(tree);
                    return op2; // Just return the "0" node
                }

                // We need to keep op1 for the side-effects. Hang it off
                // a GT_COMMA node

                tree->ChangeOper(GT_COMMA);
                return tree;
            }

            size_t abs_mult = (mult >= 0) ? mult : -mult;
            size_t lowestBit = genFindLowestBit(abs_mult);
            bool changeToShift = false;

            // is it a power of two? (positive or negative)
            if  (abs_mult == lowestBit)
            {
                    // if negative negate (min-int does not need negation)
                if (mult < 0 && mult != SSIZE_T_MIN)
                {
                    tree->gtOp.gtOp1 = op1 = gtNewOperNode(GT_NEG, op1->gtType, op1);
                    fgMorphTreeDone(op1);
                }

                // If "op2" is a constant array index, the other multiplicand must be a constant.
                // Transfer the annotation to the other one.
                if (op2->OperGet() == GT_CNS_INT &&
                    op2->gtIntCon.gtFieldSeq != nullptr &&
                    op2->gtIntCon.gtFieldSeq->IsConstantIndexFieldSeq())
                {
                    assert(op2->gtIntCon.gtFieldSeq->m_next == nullptr);
                    GenTreePtr otherOp = op1;
                    if (otherOp->OperGet() == GT_NEG)
                        otherOp = otherOp->gtOp.gtOp1;
                    assert(otherOp->OperGet() == GT_CNS_INT);
                    assert(otherOp->gtIntCon.gtFieldSeq == FieldSeqStore::NotAField());
                    otherOp->gtIntCon.gtFieldSeq = op2->gtIntCon.gtFieldSeq;
                }

                if (abs_mult == 1)
                {
                    DEBUG_DESTROY_NODE(op2);
                    DEBUG_DESTROY_NODE(tree);
                    return op1;
                }

                /* Change the multiplication into a shift by log2(val) bits */
                op2->gtIntConCommon.SetIconValue(genLog2(abs_mult));
                changeToShift = true;
            }
#if LEA_AVAILABLE
            else if ((lowestBit > 1) && jitIsScaleIndexMul(lowestBit) && optAvoidIntMult())
            {
                int     shift = genLog2(lowestBit);
                ssize_t factor = abs_mult >> shift;

                if (factor == 3 || factor == 5 || factor == 9)
                {
                    // if negative negate (min-int does not need negation)
                    if (mult < 0 && mult != SSIZE_T_MIN)
                    {
                        tree->gtOp.gtOp1 = op1 = gtNewOperNode(GT_NEG, op1->gtType, op1);
                        fgMorphTreeDone(op1);
                    }

                    GenTreePtr factorIcon = gtNewIconNode(factor, TYP_I_IMPL);
                    if (op2IsConstIndex)
                    {
                        factorIcon->AsIntCon()->gtFieldSeq = GetFieldSeqStore()->CreateSingleton(FieldSeqStore::ConstantIndexPseudoField);
                    }

                    // change the multiplication into a smaller multiplication (by 3, 5 or 9) and a shift
                    tree->gtOp.gtOp1 = op1 = gtNewOperNode(GT_MUL, tree->gtType, op1, factorIcon);
                    fgMorphTreeDone(op1);

                    op2->gtIntConCommon.SetIconValue(shift);
                    changeToShift = true;
                }
            }
#endif // LEA_AVAILABLE
            if (changeToShift)
            {
                // vnStore is null before the ValueNumber phase has run
                if (vnStore != nullptr)
                {
                    // Update the ValueNumber for 'op2', as we just changed the constant
                    fgValueNumberTreeConst(op2);
                }
                oper = GT_LSH;
                // Keep the old ValueNumber for 'tree' as the new expr
                // will still compute the same value as before
                tree->ChangeOper(oper, GenTree::PRESERVE_VN);

                goto DONE_MORPHING_CHILDREN;
            }
        }
        else if (fgOperIsBitwiseRotationRoot(oper))
        {
            tree = fgRecognizeAndMorphBitwiseRotation(tree);

            // fgRecognizeAndMorphBitwiseRotation may return a new tree
            oper = tree->OperGet();
            typ = tree->TypeGet();
            op1 = tree->gtOp.gtOp1;
            op2 = tree->gtOp.gtOp2;
        }

        break;

    case GT_CHS:
    case GT_NOT:
    case GT_NEG:

        /* Any constant cases should have been folded earlier */
        noway_assert(!op1->OperIsConst() || !opts.OptEnabled(CLFLG_CONSTANTFOLD) || optValnumCSE_phase);
        break;

    case GT_CKFINITE:

        noway_assert(varTypeIsFloating(op1->TypeGet()));

        fgAddCodeRef(compCurBB, bbThrowIndex(compCurBB), SCK_ARITH_EXCPN, fgPtrArgCntCur);
        break;

    case GT_IND:

        // Can not remove a GT_IND if it is currently a CSE candidate.
        if (gtIsActiveCSE_Candidate(tree))
            break;

        bool foldAndReturnTemp; foldAndReturnTemp = false;
        temp = nullptr;
        ival1 = 0;

        /* Try to Fold *(&X) into X */
        if (op1->gtOper == GT_ADDR) 
        {
            // Can not remove a GT_ADDR if it is currently a CSE candidate.
            if (gtIsActiveCSE_Candidate(op1))
                break;

            temp = op1->gtOp.gtOp1;         // X

            // In the test below, if they're both TYP_STRUCT, this of course does *not* mean that
            // they are the *same* struct type.  In fact, they almost certainly aren't.  If the
            // address has an associated field sequence, that identifies this case; go through
            // the "lcl_fld" path rather than this one.
            FieldSeqNode* addrFieldSeq = NULL;  // This is an unused out parameter below.
            if (   typ == temp->TypeGet()
                && !GetZeroOffsetFieldMap()->Lookup(op1, &addrFieldSeq))
            {
                foldAndReturnTemp = true;
            }
            else if (temp->OperIsLocal())
            {
                unsigned lclNum = temp->gtLclVarCommon.gtLclNum;
                LclVarDsc *  varDsc = &lvaTable[lclNum];

                // We will try to optimize when we have a promoted struct promoted with a zero lvFldOffset
                if (varDsc->lvPromoted && (varDsc->lvFldOffset == 0))
                {
                    noway_assert(varTypeIsStruct(varDsc));

                    // We will try to optimize when we have a single field struct that is being struct promoted
                    if (varDsc->lvFieldCnt == 1)
                    {
                        unsigned lclNumFld = varDsc->lvFieldLclStart;
                        // just grab the promoted field
                        LclVarDsc *  fieldVarDsc = &lvaTable[lclNumFld];

                        // Also make sure that the tree type matches the fieldVarType and that it's lvFldOffset is zero
                        if (fieldVarDsc->TypeGet() == tree->TypeGet() && (fieldVarDsc->lvFldOffset == 0))
                        {
                            // We can just use the existing promoted field LclNum
                            temp->gtLclVarCommon.SetLclNum(lclNumFld);
                            temp->gtType = fieldVarDsc->TypeGet();

                            foldAndReturnTemp = true;
                        }
                    }
                }
                // If the type of the IND (typ) is a "small int", and the type of the local has the
                // same width, then we can reduce to just the local variable -- it will be
                // correctly normalized, and signed/unsigned differences won't matter.
                //
                // The below transformation cannot be applied if the local var needs to be normalized on load.
                else if ( varTypeIsSmall(typ) && 
                         (genTypeSize(lvaTable[lclNum].lvType) == genTypeSize(typ)) && 
                         !lvaTable[lclNum].lvNormalizeOnLoad() )
                {
                    tree->gtType = temp->gtType;
                    foldAndReturnTemp = true;
                }
                else 
                {
                    // Assumes that when Lookup returns "false" it will leave "fieldSeq" unmodified (i.e. nullptr)
                    assert(fieldSeq == nullptr);
                    bool b = GetZeroOffsetFieldMap()->Lookup(op1, &fieldSeq);
                    assert(b || fieldSeq == nullptr);

                    if ((fieldSeq != nullptr) && (temp->OperGet() == GT_LCL_FLD))
                    {
                        // Append the field sequence, change the type.
                        temp->AsLclFld()->gtFieldSeq = GetFieldSeqStore()->Append(temp->AsLclFld()->gtFieldSeq, fieldSeq);
                        temp->gtType = tree->TypeGet();

                        foldAndReturnTemp = true;
                    }
                }
                // Otherwise will will fold this into a GT_LCL_FLD below
                //   where we check (temp != nullptr)
            }
            else // !temp->OperIsLocal()
            {
                // We don't try to fold away the GT_IND/GT_ADDR for this case
                temp = nullptr;
            }
        }
        else  if (op1->OperGet() == GT_ADD)
        {
            /* Try to change *(&lcl + cns) into lcl[cns] to prevent materialization of &lcl */

            if (op1->gtOp.gtOp1->OperGet() == GT_ADDR &&
                op1->gtOp.gtOp2->OperGet() == GT_CNS_INT
                && (!(opts.MinOpts() || opts.compDbgCode)))
            {
                // No overflow arithmetic with pointers
                noway_assert(!op1->gtOverflow());

                temp = op1->gtOp.gtOp1->gtOp.gtOp1;
                if (!temp->OperIsLocal())
                {
                    temp = nullptr;
                    break;
                }

                // Can not remove the GT_ADDR if it is currently a CSE candidate.
                if (gtIsActiveCSE_Candidate(op1->gtOp.gtOp1))
                    break;

                ival1 = op1->gtOp.gtOp2->gtIntCon.gtIconVal;
                fieldSeq = op1->gtOp.gtOp2->gtIntCon.gtFieldSeq;

                // Does the address have an associated zero-offset field sequence?
                FieldSeqNode* addrFieldSeq = NULL;
                if (GetZeroOffsetFieldMap()->Lookup(op1->gtOp.gtOp1, &addrFieldSeq))
                {
                    fieldSeq = GetFieldSeqStore()->Append(addrFieldSeq, fieldSeq);
                }

                if (ival1 == 0 &&
                    typ == temp->TypeGet() &&
                    temp->TypeGet() != TYP_STRUCT)
                {
                    noway_assert(!varTypeIsGC(temp->TypeGet()));
                    foldAndReturnTemp = true;
                }
                else
                {
                    // The emitter can't handle large offsets
                    if (ival1 != (unsigned short)ival1)
                        break;

                    // The emitter can get confused by invalid offsets
                    if (ival1 >= Compiler::lvaLclSize(temp->gtLclVarCommon.gtLclNum))
                        break;

#ifdef _TARGET_ARM_
                    // Check for a LclVar TYP_STRUCT with misalignment on a Floating Point field
                    //
                    if (varTypeIsFloating(tree->TypeGet()))
                    {
                        if ((ival1 % emitTypeSize(tree->TypeGet())) != 0)
                        {
                            tree->gtFlags |= GTF_IND_UNALIGNED;
                            break;
                        }
                    }
#endif
                }
                // Now we can fold this into a GT_LCL_FLD below
                //   where we check (temp != nullptr)
            }
        }

#ifdef DEBUG
        // If we have decided to fold, then temp cannot be nullptr
        if (foldAndReturnTemp)
        {
            assert(temp != nullptr);
        }
#endif

        if (temp != nullptr)
        {
            noway_assert(op1->gtOper == GT_ADD || op1->gtOper == GT_ADDR);

            // If we haven't already decided to fold this expression
            //
            if (!foldAndReturnTemp)
            {
                noway_assert(temp->OperIsLocal());
                LclVarDsc* varDsc = &(lvaTable[temp->AsLclVarCommon()->gtLclNum]);
                // Make sure we don't separately promote the fields of this struct.
                if (varDsc->lvRegStruct)
                {
                    // We can enregister, but can't promote.
                    varDsc->lvPromoted = false;
                }
                else
                {
                    lvaSetVarDoNotEnregister(temp->gtLclVarCommon.gtLclNum DEBUGARG(DNER_LocalField));
                }

                // We will turn a GT_LCL_VAR into a GT_LCL_FLD with an gtLclOffs of 'ival'
                // or if we already have a GT_LCL_FLD we will adjust the gtLclOffs by adding 'ival'
                // Then we change the type of the GT_LCL_FLD to match the orginal GT_IND type.
                //
                if (temp->OperGet() == GT_LCL_FLD)
                {
                    temp->AsLclFld()->gtLclOffs += (unsigned short)ival1;
                    temp->AsLclFld()->gtFieldSeq =
                        GetFieldSeqStore()->Append(temp->AsLclFld()->gtFieldSeq, fieldSeq);
                }
                else
                {
                    temp->ChangeOper(GT_LCL_FLD);  // Note that this makes the gtFieldSeq "NotAField"...
                    temp->AsLclFld()->gtLclOffs = (unsigned short)ival1;
                    if (fieldSeq != NULL)          // If it does represent a field, note that.
                        temp->AsLclFld()->gtFieldSeq = fieldSeq;
                }
                temp->gtType = tree->gtType;
                foldAndReturnTemp = true;
            }

            assert(foldAndReturnTemp == true);

            // Keep the DONT_CSE flag in sync
            // (i.e keep the original value of this flag from tree)
            // as it can be set for 'temp' because a GT_ADDR always marks it for it's op1
            //
            temp->gtFlags &= ~GTF_DONT_CSE;
            temp->gtFlags |= (tree->gtFlags & GTF_DONT_CSE);

            noway_assert(op1->gtOper == GT_ADD || op1->gtOper == GT_ADDR);
            noway_assert(temp->gtType == tree->gtType);

            if (op1->OperGet() == GT_ADD)
            {
                DEBUG_DESTROY_NODE(op1->gtOp.gtOp1);    // GT_ADDR
                DEBUG_DESTROY_NODE(op1->gtOp.gtOp2);    // GT_CNS_INT
            }
            DEBUG_DESTROY_NODE(op1);                    // GT_ADD or GT_ADDR
            DEBUG_DESTROY_NODE(tree);                   // GT_IND

            return temp;
        }

        // Only do this optimization when we are in the global optimizer. Doing this after value numbering
        // could result in an invalid value number for the newly generated GT_IND node.
        if ((op1->OperGet() == GT_COMMA) && fgGlobalMorph)
        {
            // Perform the transform IND(COMMA(x, ..., z)) == COMMA(x, ..., IND(z)).
            // TBD: this transformation is currently necessary for correctness -- it might
            // be good to analyze the failures that result if we don't do this, and fix them
            // in other ways.  Ideally, this should be optional.
            GenTreePtr commaNode = op1;
            unsigned treeFlags = tree->gtFlags;
            commaNode->gtType = typ;
            commaNode->gtFlags = (treeFlags & ~GTF_REVERSE_OPS); // Bashing the GT_COMMA flags here is dangerous, clear the GTF_REVERSE_OPS at least.
#ifdef DEBUG
            commaNode->gtFlags |= GTF_MORPHED;
#endif
            while (commaNode->gtOp.gtOp2->gtOper == GT_COMMA)
            {
                commaNode = commaNode->gtOp.gtOp2;
                commaNode->gtType = typ;
                commaNode->gtFlags = (treeFlags & ~GTF_REVERSE_OPS); // Bashing the GT_COMMA flags here is dangerous, clear the GTF_REVERSE_OPS at least.
#ifdef DEBUG
                commaNode->gtFlags |= GTF_MORPHED;
#endif
            }
            bool wasArrIndex = (tree->gtFlags & GTF_IND_ARR_INDEX) != 0;
            ArrayInfo arrInfo;
            if (wasArrIndex)
            {
                bool b = GetArrayInfoMap()->Lookup(tree, &arrInfo);
                assert(b);
                GetArrayInfoMap()->Remove(tree);
            }
            tree = op1;
            op1 = gtNewOperNode(GT_IND, typ, commaNode->gtOp.gtOp2);
            op1->gtFlags = treeFlags;
            if (wasArrIndex)
            {
                GetArrayInfoMap()->Set(op1, arrInfo);
            }
#ifdef DEBUG
            op1->gtFlags |= GTF_MORPHED;
#endif
            commaNode->gtOp.gtOp2 = op1;
            return tree;
        }

        break;

    case GT_ADDR:

        // Can not remove op1 if it is currently a CSE candidate.
        if (gtIsActiveCSE_Candidate(op1))
            break;

        if (op1->OperGet() == GT_IND)
        {
            if ((op1->gtFlags & GTF_IND_ARR_INDEX) == 0)
            {
                // Can not remove a GT_ADDR if it is currently a CSE candidate.
                if (gtIsActiveCSE_Candidate(tree))
                    break;

                // Perform the transform ADDR(IND(...)) == (...).  
                GenTreePtr addr = op1->gtOp.gtOp1;

                noway_assert(varTypeIsGC(addr->gtType) || addr->gtType == TYP_I_IMPL);

                DEBUG_DESTROY_NODE(op1);
                DEBUG_DESTROY_NODE(tree);

                return addr;
            }
        }
        else if (op1->gtOper == GT_CAST)
        {
            GenTreePtr casting = op1->gtCast.CastOp();
            if (casting->gtOper == GT_LCL_VAR || casting->gtOper == GT_CLS_VAR)
            {
                DEBUG_DESTROY_NODE(op1);
                tree->gtOp.gtOp1 = op1 = casting;
            }
        }
        else if ((op1->gtOper == GT_COMMA) && !optValnumCSE_phase)
        {
            // Perform the transform ADDR(COMMA(x, ..., z)) == COMMA(x, ..., ADDR(z)).
            // (Be sure to mark "z" as an l-value...)
            GenTreePtr commaNode = op1;
            while (commaNode->gtOp.gtOp2->gtOper == GT_COMMA)
            {
                commaNode = commaNode->gtOp.gtOp2;
            }
            // The top-level addr might be annotated with a zeroOffset field.
            FieldSeqNode* zeroFieldSeq = nullptr;
            bool isZeroOffset = GetZeroOffsetFieldMap()->Lookup(tree, &zeroFieldSeq);
            tree = op1;
            commaNode->gtOp.gtOp2->gtFlags |= GTF_DONT_CSE;

            // If the node we're about to put under a GT_ADDR is a GT_IND, the indirection
            // doesn't need to be materialized, since we only want the addressing mode. Because 
            // of this, this GT_IND is not a faulting indirection and we don't have to extract it
            // as a side effect.
            GenTree* commaOp2 = commaNode->gtOp.gtOp2;
            if (commaOp2->gtOper == GT_IND)
            {
                commaOp2->gtFlags |= GTF_IND_NONFAULTING;
            }

            op1 = gtNewOperNode(GT_ADDR, TYP_BYREF, commaOp2);

            if (isZeroOffset)
            {
                // Transfer the annotation to the new GT_ADDR node.
                GetZeroOffsetFieldMap()->Set(op1, zeroFieldSeq);
            }
            commaNode->gtOp.gtOp2 = op1;
            // Originally, I gave all the comma nodes type "byref".  But the ADDR(IND(x)) == x transform
            // might give op1 a type different from byref (like, say, native int).  So now go back and give
            // all the comma nodes the type of op1.
            commaNode = tree;
            while (commaNode->gtOper == GT_COMMA)
            {
                commaNode->gtType = op1->gtType; commaNode->gtFlags |= op1->gtFlags;
#ifdef DEBUG
                commaNode->gtFlags |= GTF_MORPHED;
#endif
                commaNode = commaNode->gtOp.gtOp2;
            }

            return tree;
        }

        /* op1 of a GT_ADDR is an l-value. Only r-values can be CSEed */
        op1->gtFlags |= GTF_DONT_CSE;
        break;

    case GT_COLON:
        if (fgGlobalMorph)
        {
            /* Mark the nodes that are conditionally executed */
            fgWalkTreePre(&tree, gtMarkColonCond);
        }
        /* Since we're doing this postorder we clear this if it got set by a child */
        fgRemoveRestOfBlock = false;
        break;

    case GT_COMMA:

        /* Special case: trees that don't produce a value */
        if  ((op2->OperKind() & GTK_ASGOP) ||
             (op2->OperGet() == GT_COMMA && op2->TypeGet() == TYP_VOID) ||
             fgIsThrow(op2))
        {
            typ = tree->gtType = TYP_VOID;
        }

        // If we are in the Valuenum CSE phase then don't morph away anything as these
        // nodes may have CSE defs/uses in them.
        //
        if (!optValnumCSE_phase)
        {
            //Extract the side effects from the left side of the comma.  Since they don't "go" anywhere, this is
            //all we need.

            GenTreePtr op1SideEffects = NULL;
            // The addition of "GTF_MAKE_CSE" below prevents us from throwing away (for example)
            // hoisted expressions in loops.
            gtExtractSideEffList(op1, &op1SideEffects, (GTF_SIDE_EFFECT | GTF_MAKE_CSE));
            if (op1SideEffects)
            {
                //Replace the left hand side with the side effect list.
                tree->gtOp.gtOp1 = op1SideEffects;
                tree->gtFlags |= (op1SideEffects->gtFlags & GTF_ALL_EFFECT);
            }
            else
            {
                /* The left operand is worthless, throw it away */
                if (lvaLocalVarRefCounted)
                {
                    lvaRecursiveDecRefCounts(op1);
                }
                op2->gtFlags |= (tree->gtFlags & (GTF_DONT_CSE | GTF_LATE_ARG));
                DEBUG_DESTROY_NODE(tree);
                DEBUG_DESTROY_NODE(op1);
                return op2;
            }

            /* If the right operand is just a void nop node, throw it away */
            if  (op2->IsNothingNode() && op1->gtType == TYP_VOID)
            {
                op1->gtFlags |= (tree->gtFlags & (GTF_DONT_CSE | GTF_LATE_ARG));
                DEBUG_DESTROY_NODE(tree);
                DEBUG_DESTROY_NODE(op2);
                return op1;
            }
        }

        break;

    case GT_JTRUE:

        /* Special case if fgRemoveRestOfBlock is set to true */
        if (fgRemoveRestOfBlock)
        {
            if (fgIsCommaThrow(op1, true))
            {
                GenTreePtr throwNode = op1->gtOp.gtOp1;
                noway_assert(throwNode->gtType == TYP_VOID);

                return throwNode;
            }

            noway_assert(op1->OperKind() & GTK_RELOP);
            noway_assert(op1->gtFlags    & GTF_EXCEPT);

            // We need to keep op1 for the side-effects. Hang it off
            // a GT_COMMA node

            tree->ChangeOper(GT_COMMA);
            tree->gtOp.gtOp2 = op2 = gtNewNothingNode();

            // Additionally since we're eliminating the JTRUE
            // codegen won't like it if op1 is a RELOP of longs, floats or doubles.
            // So we change it into a GT_COMMA as well.
            op1->ChangeOper(GT_COMMA);
            op1->gtType = op1->gtOp.gtOp1->gtType;

            return tree;
        }

    default:
        break;
    }

    noway_assert(oper == tree->gtOper);

    // If we are in the Valuenum CSE phase then don't morph away anything as these
    // nodes may have CSE defs/uses in them.
    //
    if (!optValnumCSE_phase && (oper != GT_ASG) && (oper != GT_COLON) && !tree->IsList())
    {
        /* Check for op1 as a GT_COMMA with a unconditional throw node */
        if (op1 && fgIsCommaThrow(op1, true))
        {
            if ((op1->gtFlags & GTF_COLON_COND) == 0)
            {
                /* We can safely throw out the rest of the statements */
                fgRemoveRestOfBlock = true;
            }

            GenTreePtr throwNode = op1->gtOp.gtOp1;
            noway_assert(throwNode->gtType == TYP_VOID);

            if (oper == GT_COMMA)
            {
                /* Both tree and op1 are GT_COMMA nodes */
                /* Change the tree's op1 to the throw node: op1->gtOp.gtOp1 */
                tree->gtOp.gtOp1 = throwNode;
                return tree;
            }
            else if (oper != GT_NOP)
            {
                if (genActualType(typ) == genActualType(op1->gtType))
                {
                    /* The types match so, return the comma throw node as the new tree */
                    return op1;
                }
                else
                {
                    if (typ == TYP_VOID)
                    {
                        // Return the throw node
                        return throwNode;
                    }
                    else
                    {
                        GenTreePtr commaOp2 = op1->gtOp.gtOp2;

                        // need type of oper to be same as tree
                        if (typ == TYP_LONG)
                        {
                            commaOp2->ChangeOperConst(GT_CNS_NATIVELONG);
                            commaOp2->gtIntConCommon.SetLngValue(0);
                            /* Change the types of oper and commaOp2 to TYP_LONG */
                            op1->gtType = commaOp2->gtType = TYP_LONG;
                        }
                        else if (varTypeIsFloating(typ))
                        {
                            commaOp2->ChangeOperConst(GT_CNS_DBL);
                            commaOp2->gtDblCon.gtDconVal = 0.0;
                            /* Change the types of oper and commaOp2 to TYP_DOUBLE */
                            op1->gtType = commaOp2->gtType = TYP_DOUBLE;
                        }
                        else
                        {
                            commaOp2->ChangeOperConst(GT_CNS_INT);
                            commaOp2->gtIntConCommon.SetIconValue(0);
                            /* Change the types of oper and commaOp2 to TYP_INT */
                            op1->gtType = commaOp2->gtType = TYP_INT;
                        }

                        /* Return the GT_COMMA node as the new tree */
                        return op1;
                    }
                }
            }
        }

        /* Check for op2 as a GT_COMMA with a unconditional throw */

        if (op2 && fgIsCommaThrow(op2, true))
        {
            if ((op2->gtFlags & GTF_COLON_COND) == 0)
            {
                /* We can safely throw out the rest of the statements */
                fgRemoveRestOfBlock = true;
            }

            // If op1 has no side-effects
            if ((op1->gtFlags & GTF_ALL_EFFECT) == 0)
            {
                // If tree is an asg node
                if (tree->OperIsAssignment())
                {
                    /* Return the throw node as the new tree */
                    return op2->gtOp.gtOp1;
                }

                if (tree->OperGet() == GT_ARR_BOUNDS_CHECK)
                {
                    /* Return the throw node as the new tree */
                    return op2->gtOp.gtOp1;
                }

                // If tree is a comma node
                if (tree->OperGet() == GT_COMMA)
                {
                    /* Return the throw node as the new tree */
                     return op2->gtOp.gtOp1;
                }

                /* for the shift nodes the type of op2 can differ from the tree type */
                if ((typ == TYP_LONG) && (genActualType(op2->gtType) == TYP_INT))
                {
                    noway_assert(GenTree::OperIsShiftOrRotate(oper));

                    GenTreePtr commaOp2 = op2->gtOp.gtOp2;

                    commaOp2->ChangeOperConst(GT_CNS_NATIVELONG);
                    commaOp2->gtIntConCommon.SetLngValue(0);

                    /* Change the types of oper and commaOp2 to TYP_LONG */
                    op2->gtType = commaOp2->gtType = TYP_LONG;
                }

                if ((genActualType(typ) == TYP_INT) && (genActualType(op2->gtType) == TYP_LONG ||
                                                        varTypeIsFloating(op2->TypeGet())))
                {
                    // An example case is comparison (say GT_GT) of two longs or floating point values.

                    GenTreePtr commaOp2 = op2->gtOp.gtOp2;

                    commaOp2->ChangeOperConst(GT_CNS_INT);
                    commaOp2->gtIntCon.gtIconVal = 0;
                    /* Change the types of oper and commaOp2 to TYP_INT */
                    op2->gtType = commaOp2->gtType = TYP_INT;
                }

                if ((typ == TYP_BYREF) && (genActualType(op2->gtType) == TYP_I_IMPL))
                {
                    noway_assert(tree->OperGet() == GT_ADD);

                    GenTreePtr commaOp2 = op2->gtOp.gtOp2;

                    commaOp2->ChangeOperConst(GT_CNS_INT);
                    commaOp2->gtIntCon.gtIconVal = 0;
                    /* Change the types of oper and commaOp2 to TYP_BYREF */
                    op2->gtType = commaOp2->gtType = TYP_BYREF;
                }

                /* types should now match */
                noway_assert( (genActualType(typ) == genActualType(op2->gtType)));

                /* Return the GT_COMMA node as the new tree */
                return op2;
            }
        }
    }

    /*-------------------------------------------------------------------------
     * Optional morphing is done if tree transformations is permitted
     */

    if  ((opts.compFlags & CLFLG_TREETRANS) == 0)
        return tree;

    tree = fgMorphSmpOpOptional(tree->AsOp());

    } // extra scope for gcc workaround
    return tree;
}
#ifdef _PREFAST_
#pragma warning(pop)
#endif


GenTree* Compiler::fgMorphSmpOpOptional(GenTreeOp* tree)
{
    genTreeOps oper = tree->gtOper;
    GenTree* op1 = tree->gtOp1;
    GenTree* op2 = tree->gtOp2;
    var_types       typ     = tree->TypeGet();

    if  (GenTree::OperIsCommutative(oper))
    {
        /* Swap the operands so that the more expensive one is 'op1' */

        if  (tree->gtFlags & GTF_REVERSE_OPS)
        {
            tree->gtOp1 = op2;
            tree->gtOp2 = op1;

            op2 = op1;
            op1 = tree->gtOp1;

            tree->gtFlags &= ~GTF_REVERSE_OPS;
        }

        if (oper == op2->gtOper)
        {
            /*  Reorder nested operators at the same precedence level to be
                left-recursive. For example, change "(a+(b+c))" to the
                equivalent expression "((a+b)+c)".
             */

            /* Things are handled differently for floating-point operators */

            if  (!varTypeIsFloating(tree->TypeGet()))
            {
                fgMoveOpsLeft(tree);
                op1 = tree->gtOp1;
                op2 = tree->gtOp2;
            }
        }

    }

#if REARRANGE_ADDS

    /* Change "((x+icon)+y)" to "((x+y)+icon)"
       Don't reorder floating-point operations */

    if  ((oper        == GT_ADD) && !tree->gtOverflow() &&
         (op1->gtOper == GT_ADD) && ! op1->gtOverflow() && varTypeIsIntegralOrI(typ))
    {
        GenTreePtr      ad2 = op1->gtOp.gtOp2;

        if  (op2->OperIsConst() == 0 &&
             ad2->OperIsConst() != 0)
        {
            //This takes
            //       + (tree)
            //      / \
            //     /   \
            //    /     \
            //   + (op1) op2
            //  / \
            //     \
            //     ad2
            //
            // And it swaps ad2 and op2.  If (op2) is varTypeIsGC, then this implies that (tree) is
            // varTypeIsGC.  If (op1) is not, then when we swap (ad2) and (op2), then we have a TYP_INT node
            // (op1) with a child that is varTypeIsGC.  If we encounter that situation, make (op1) the same
            // type as (tree).
            //
            // Also, if (ad2) is varTypeIsGC then (tree) must also be (since op1 is), so no fixing is
            // necessary

            if (varTypeIsGC(op2->TypeGet()))
            {
                noway_assert(varTypeIsGC(typ));
                op1->gtType = typ;
            }
            tree->gtOp2 = ad2;

            op1 ->gtOp.gtOp2 = op2;
            op1->gtFlags    |= op2->gtFlags & GTF_ALL_EFFECT;

            op2 = tree->gtOp2;
        }
    }

#endif

    /*-------------------------------------------------------------------------
     * Perform optional oper-specific postorder morphing
     */

    switch (oper)
    {
        genTreeOps      cmop;
        bool            dstIsSafeLclVar;

    case GT_ASG:

        /* We'll convert "a = a <op> x" into "a <op>= x"                     */
        /*     and also  "a = x <op> a" into "a <op>= x" for communative ops */

#if !LONG_ASG_OPS
        if  (typ == TYP_LONG)
            break;
#endif

        /* Make sure we're allowed to do this */

        if (optValnumCSE_phase)
        {
            // It is not safe to reorder/delete CSE's
            break;
        }

        /* Are we assigning to a GT_LCL_VAR ? */

        dstIsSafeLclVar = (op1->gtOper == GT_LCL_VAR);

        /* If we have a GT_LCL_VAR, then is the address taken? */
        if (dstIsSafeLclVar)
        {
            unsigned     lclNum = op1->gtLclVarCommon.gtLclNum;
            LclVarDsc *  varDsc = lvaTable + lclNum;

            noway_assert(lclNum < lvaCount);

            /* Is the address taken? */
            if  (varDsc->lvAddrExposed)
            {
                dstIsSafeLclVar = false;
            }
            else if (op2->gtFlags & GTF_ASG)
            {
                break;
            }
        }

        if (!dstIsSafeLclVar)
        {
            if (op2->gtFlags & GTF_ASG)
                break;

            if  ((op2->gtFlags & GTF_CALL) && (op1->gtFlags & GTF_ALL_EFFECT))
                break;
        }

        /* Special case: a cast that can be thrown away */

        if  (op1->gtOper == GT_IND  &&
             op2->gtOper == GT_CAST &&
             !op2->gtOverflow()      )
        {
            var_types       srct;
            var_types       cast;
            var_types       dstt;

            srct =             op2->gtCast.CastOp()->TypeGet();
            cast = (var_types) op2->CastToType();
            dstt =             op1->TypeGet();

            /* Make sure these are all ints and precision is not lost */

            if  (cast >= dstt && dstt <= TYP_INT && srct <= TYP_INT)
                op2 = tree->gtOp2 = op2->gtCast.CastOp();
        }

        /* Make sure we have the operator range right */

        noway_assert(GT_SUB == GT_ADD + 1);
        noway_assert(GT_MUL == GT_ADD + 2);
        noway_assert(GT_DIV == GT_ADD + 3);
        noway_assert(GT_MOD == GT_ADD + 4);
        noway_assert(GT_UDIV== GT_ADD + 5);
        noway_assert(GT_UMOD== GT_ADD + 6);

        noway_assert(GT_OR  == GT_ADD + 7);
        noway_assert(GT_XOR == GT_ADD + 8);
        noway_assert(GT_AND == GT_ADD + 9);

        noway_assert(GT_LSH == GT_ADD + 10);
        noway_assert(GT_RSH == GT_ADD + 11);
        noway_assert(GT_RSZ == GT_ADD + 12);

        /* Check for a suitable operator on the RHS */

        cmop = op2->OperGet();

        switch (cmop)
        {
        case GT_NEG:
            // GT_CHS only supported for integer types
            if  ( varTypeIsFloating(tree->TypeGet()))
                break;

            goto ASG_OP;

        case GT_MUL:
            // GT_ASG_MUL only supported for floating point types
            if  (!varTypeIsFloating(tree->TypeGet()))
                break;

            __fallthrough;

        case GT_ADD:
        case GT_SUB:
            if (op2->gtOverflow())
            {
                /* Disable folding into "<op>=" if the result can be
                   visible to anyone as <op> may throw an exception and
                   the assignment should not proceed
                   We are safe with an assignment to a local variables
                 */
                if (ehBlockHasExnFlowDsc(compCurBB))
                    break;
                if (!dstIsSafeLclVar)
                    break;
            }
#ifndef _TARGET_AMD64_
            // This is hard for byte-operations as we need to make
            // sure both operands are in RBM_BYTE_REGS.
            if (varTypeIsByte(op2->TypeGet()))
                break;
#endif // _TARGET_AMD64_
            goto ASG_OP;

        case GT_DIV:
        case GT_UDIV:
            // GT_ASG_DIV only supported for floating point types
            if  (!varTypeIsFloating(tree->TypeGet()))
                break;

        case GT_LSH:
        case GT_RSH:
        case GT_RSZ:

#if LONG_ASG_OPS

            if  (typ == TYP_LONG)
                break;
#endif

        case GT_OR:
        case GT_XOR:
        case GT_AND:

#if LONG_ASG_OPS

            /* TODO: allow non-const long assignment operators */

            if  (typ == TYP_LONG && op2->gtOp.gtOp2->gtOper != GT_CNS_LNG)
                break;
#endif

ASG_OP:
            {
                bool bReverse = false;
                bool bAsgOpFoldable = fgShouldCreateAssignOp(tree, &bReverse);
                if (bAsgOpFoldable)
                {
                    if (bReverse)
                    {
                        // We will transform this from "a = x <op> a" to "a <op>= x"
                        // so we can now destroy the duplicate "a"
                        DEBUG_DESTROY_NODE(op2->gtOp.gtOp2);
                        op2->gtOp.gtOp2 = op2->gtOp.gtOp1;
                    }

                    /* Special case: "x |= -1" and "x &= 0" */
                    if  (cmop == GT_AND || cmop == GT_OR)
                    {
                        if  (op2->gtOp.gtOp2->IsCnsIntOrI())
                        {
                            ssize_t     icon = op2->gtOp.gtOp2->gtIntCon.gtIconVal;

                            noway_assert(typ <= TYP_UINT);

                            if  ((cmop == GT_AND && icon == 0) ||
                                (cmop == GT_OR  && icon == -1))
                            {
                                /* Simply change to an assignment */
                                tree->gtOp2 = op2->gtOp.gtOp2;
                                break;
                            }
                        }
                    }

                    if  (cmop == GT_NEG)
                    {
                        /* This is "x = -x;", use the flipsign operator */

                        tree->ChangeOper  (GT_CHS);

                        if  (op1->gtOper == GT_LCL_VAR)
                            op1->gtFlags |= GTF_VAR_USEASG;

                        tree->gtOp2 = gtNewIconNode(0, op1->TypeGet());

                        break;
                    }

                    if (cmop == GT_RSH && varTypeIsSmall(op1->TypeGet()) && varTypeIsUnsigned(op1->TypeGet()))
                    {
                        // Changing from x = x op y to x op= y when x is a small integer type
                        // makes the op size smaller (originally the op size was 32 bits, after
                        // sign or zero extension of x, and there is an implicit truncation in the
                        // assignment).
                        // This is ok in most cases because the upper bits were
                        // lost when assigning the op result to a small type var,
                        // but it may not be ok for the right shift operation where the higher bits
                        // could be shifted into the lower bits and preserved.
                        // Signed right shift of signed x still works (i.e. (sbyte)((int)(sbyte)x >>signed y) == (sbyte)x >>signed y))
                        // as do unsigned right shift ((ubyte)((int)(ubyte)x >>unsigned y) == (ubyte)x >>unsigned y), but
                        // signed right shift of an unigned small type may give the wrong result:
                        // e.g. (ubyte)((int)(ubyte)0xf0 >>signed 4) == 0x0f,
                        // but  (ubyte)0xf0 >>signed 4 == 0xff which is incorrect.
                        // The result becomes correct if we use >>unsigned instead of >>signed.
                        noway_assert(op1->TypeGet() == op2->gtOp.gtOp1->TypeGet());
                        cmop = GT_RSZ;
                    }

                    /* Replace with an assignment operator */
                    noway_assert(GT_ADD - GT_ADD == GT_ASG_ADD - GT_ASG_ADD);
                    noway_assert(GT_SUB - GT_ADD == GT_ASG_SUB - GT_ASG_ADD);
                    noway_assert(GT_OR  - GT_ADD == GT_ASG_OR  - GT_ASG_ADD);
                    noway_assert(GT_XOR - GT_ADD == GT_ASG_XOR - GT_ASG_ADD);
                    noway_assert(GT_AND - GT_ADD == GT_ASG_AND - GT_ASG_ADD);
                    noway_assert(GT_LSH - GT_ADD == GT_ASG_LSH - GT_ASG_ADD);
                    noway_assert(GT_RSH - GT_ADD == GT_ASG_RSH - GT_ASG_ADD);
                    noway_assert(GT_RSZ - GT_ADD == GT_ASG_RSZ - GT_ASG_ADD);

                    tree->SetOper((genTreeOps)(cmop - GT_ADD + GT_ASG_ADD));
                    tree->gtOp2 = op2->gtOp.gtOp2;

                    /* Propagate GTF_OVERFLOW */

                    if (op2->gtOverflowEx())
                    {
                        tree->gtType   =  op2->gtType;
                        tree->gtFlags |= (op2->gtFlags &
                            (GTF_OVERFLOW|GTF_EXCEPT|GTF_UNSIGNED));
                    }

#if FEATURE_SET_FLAGS

                    /* Propagate GTF_SET_FLAGS */
                    if (op2->gtSetFlags())
                    {
                        tree->gtRequestSetFlags();
                    }

#endif // FEATURE_SET_FLAGS

                    DEBUG_DESTROY_NODE(op2);
                    op2 = tree->gtOp2;

                    /* The target is used as well as being defined */
                    if (op1->OperIsLocal())
                        op1->gtFlags |= GTF_VAR_USEASG;


#if CPU_HAS_FP_SUPPORT
                    /* Check for the special case "x += y * x;" */

                    // GT_ASG_MUL only supported for floating point types
                    if (cmop != GT_ADD && cmop != GT_SUB)
                        break;

                    if  (op2->gtOper == GT_MUL && varTypeIsFloating(tree->TypeGet()))
                    {
                        if      (GenTree::Compare(op1, op2->gtOp.gtOp1))
                        {
                            /* Change "x += x * y" into "x *= (y + 1)" */

                            op2 = op2->gtOp.gtOp2;
                        }
                        else if (GenTree::Compare(op1, op2->gtOp.gtOp2))
                        {
                            /* Change "x += y * x" into "x *= (y + 1)" */

                            op2 = op2->gtOp.gtOp1;
                        }
                        else
                            break;

                        op1 = gtNewDconNode(1.0);

                        /* Now make the "*=" node */

                        if (cmop == GT_ADD)
                        {
                            /* Change "x += x * y" into "x *= (y + 1)" */

                            tree->gtOp2 = op2 = gtNewOperNode(GT_ADD,
                                tree->TypeGet(),
                                op2,
                                op1);
                        }
                        else
                        {
                            /* Change "x -= x * y" into "x *= (1 - y)" */

                            noway_assert(cmop == GT_SUB);
                            tree->gtOp2 = op2 = gtNewOperNode(GT_SUB,
                                tree->TypeGet(),
                                op1,
                                op2);
                        }
                        tree->ChangeOper(GT_ASG_MUL);
                    }
#endif // CPU_HAS_FP_SUPPORT
                }
            }

            break;

        case GT_NOT:

            /* Is the destination identical to the first RHS sub-operand? */

            if  (GenTree::Compare(op1, op2->gtOp.gtOp1))
            {
                /* This is "x = ~x" which is the same as "x ^= -1"
                 * Transform the node into a GT_ASG_XOR */

                noway_assert(genActualType(typ) == TYP_INT ||
                       genActualType(typ) == TYP_LONG);

                op2->gtOp.gtOp2 = (genActualType(typ) == TYP_INT)
                                    ? gtNewIconNode(-1)
                                    : gtNewLconNode(-1);

                cmop = GT_XOR;
                goto ASG_OP;
            }

            break;
        default:
            break;
        }

        break;

    case GT_MUL:

        /* Check for the case "(val + icon) * icon" */

        if  (op2->gtOper == GT_CNS_INT &&
             op1->gtOper == GT_ADD)
        {
            GenTreePtr  add = op1->gtOp.gtOp2;

            if  (add->IsCnsIntOrI() && (op2->GetScaleIndexMul() != 0))
            {
                if (tree->gtOverflow() || op1->gtOverflow())
                {
                    break;
                }

                ssize_t     imul = op2->gtIntCon.gtIconVal;
                ssize_t     iadd = add->gtIntCon.gtIconVal;

                /* Change '(val + iadd) * imul' -> '(val * imul) + (iadd * imul)' */

                oper         = GT_ADD;
                tree->ChangeOper(oper);

                op2->gtIntCon.gtIconVal = iadd * imul;

                op1->ChangeOper(GT_MUL);

                add->gtIntCon.gtIconVal = imul;
#ifdef _TARGET_64BIT_
                if (add->gtType == TYP_INT)
                {
                    // we need to properly re-sign-extend or truncate after multiplying two int constants above
                    add->AsIntCon()->TruncateOrSignExtend32();
                }
#endif //_TARGET_64BIT_
            }
        }

        break;

    case GT_DIV:

        /* For "val / 1", just return "val" */

        if ((op2->gtOper == GT_CNS_INT) && (op2->gtIntConCommon.IconValue() == 1))
        {
            DEBUG_DESTROY_NODE(tree);
            return op1;
        }
        // Do this for "long" constants as well as ints.
        else if ((op2->gtOper == GT_CNS_LNG) && (op2->gtIntConCommon.LngValue() == 1))
        {
            DEBUG_DESTROY_NODE(tree);
            return op1;
        }

        break;

    case GT_LSH:

        /* Check for the case "(val + icon) << icon" */

        if  (op2->IsCnsIntOrI() &&
             op1->gtOper == GT_ADD && !op1->gtOverflow())
        {
            GenTreePtr  cns = op1->gtOp.gtOp2;

            if  (cns->IsCnsIntOrI() && (op2->GetScaleIndexShf() != 0))
            {
                ssize_t     ishf = op2->gtIntConCommon.IconValue();
                ssize_t     iadd = cns->gtIntConCommon.IconValue();

//                  printf("Changing '(val+icon1)<<icon2' into '(val<<icon2+icon1<<icon2)'\n");

                /* Change "(val + iadd) << ishf" into "(val<<ishf + iadd<<ishf)" */

                tree->ChangeOper(GT_ADD);
                ssize_t     result = iadd << ishf;
                op2->gtIntConCommon.SetIconValue(result);
#ifdef _TARGET_64BIT_
                if (op1->gtType == TYP_INT)
                {
                    op2->AsIntCon()->TruncateOrSignExtend32();
                }
#endif // _TARGET_64BIT_
                
                // we are reusing the shift amount node here, but the type we want is that of the shift result
                op2->gtType = op1->gtType;

                if (cns->gtOper == GT_CNS_INT &&
                    cns->gtIntCon.gtFieldSeq != nullptr &&
                    cns->gtIntCon.gtFieldSeq->IsConstantIndexFieldSeq())
                {
                    assert(cns->gtIntCon.gtFieldSeq->m_next == nullptr);
                    op2->gtIntCon.gtFieldSeq = cns->gtIntCon.gtFieldSeq;
                }

                op1->ChangeOper(GT_LSH);

                cns->gtIntConCommon.SetIconValue(ishf);
            }
        }

        break;

    case GT_XOR:

        if (!optValnumCSE_phase)
        {
            /* "x ^ -1" is "~x" */
            
            if ((op2->gtOper == GT_CNS_INT) && (op2->gtIntConCommon.IconValue() == -1))
            {
                tree->ChangeOper(GT_NOT);
                tree->gtOp2 = NULL;
                DEBUG_DESTROY_NODE(op2);
            }
            else if ((op2->gtOper == GT_CNS_LNG) && (op2->gtIntConCommon.LngValue() == -1))
            {
                tree->ChangeOper(GT_NOT);
                tree->gtOp2 = NULL;
                DEBUG_DESTROY_NODE(op2);
            }
            else if ((op2->gtOper == GT_CNS_INT) && (op2->gtIntConCommon.IconValue() == 1) &&
                     op1->OperIsCompare())
            {
                /* "binaryVal ^ 1" is "!binaryVal" */
                gtReverseCond(op1);
                DEBUG_DESTROY_NODE(op2);
                DEBUG_DESTROY_NODE(tree);
                return op1;
            }
        }

        break;

    case GT_INITBLK:
        return fgMorphInitBlock(tree);
        break;

    case GT_COPYOBJ:
    case GT_COPYBLK:
        return fgMorphCopyBlock(tree);
        break;

    default:
        break;
    }
    return tree;
}


// code to generate a magic number and shift amount for the magic number division 
// optimization.  This code is previously from UTC where it notes it was taken from
// _The_PowerPC_Compiler_Writer's_Guide_, pages 57-58.
// The paper it is based on is "Division by invariant integers using multiplication"
// by Torbjorn Granlund and Peter L. Montgomery in PLDI 94

template <typename T>
T GetSignedMagicNumberForDivide(T denom, int *shift /*out*/)
{
    // static SMAG smag;
    const int bits = sizeof(T) * 8;
    const int bits_minus_1 = bits - 1;

    typedef typename jitstd::make_unsigned<T>::type UT;

    const UT two_nminus1 = UT(1) << bits_minus_1;

    int p;
    UT absDenom;
    UT absNc;
    UT delta;
    UT q1;
    UT r1;
    UT r2;
    UT q2;
    UT t;
    T result_magic;
    int result_shift;
    int iters = 0;

    absDenom = abs(denom);
    t = two_nminus1 + ((unsigned int)denom >> 31);
    absNc = t - 1 - (t % absDenom);     // absolute value of nc
    p = bits_minus_1;                   // initialize p
    q1 = two_nminus1 / absNc;           // initialize q1 = 2^p / abs(nc)
    r1 = two_nminus1 - (q1 * absNc);    // initialize r1 = rem(2^p, abs(nc))
    q2 = two_nminus1 / absDenom;        // initialize q1 = 2^p / abs(denom)
    r2 = two_nminus1 - (q2 * absDenom); // initialize r1 = rem(2^p, abs(denom))

    do {
        iters++;
        p++;
        q1 *= 2;                        // update q1 = 2^p / abs(nc)
        r1 *= 2;                        // update r1 = rem(2^p / abs(nc))

        if (r1 >= absNc) {              // must be unsigned comparison
            q1++;
            r1 -= absNc;
        }

        q2 *= 2;                        // update q2 = 2^p / abs(denom)
        r2 *= 2;                        // update r2 = rem(2^p / abs(denom))

        if (r2 >= absDenom) {           // must be unsigned comparison
            q2++;
            r2 -= absDenom;
        }

        delta = absDenom - r2;
    } while (q1 < delta || (q1 == delta && r1 == 0));

    result_magic = q2 + 1;              // resulting magic number
    if (denom < 0) {
        result_magic = -result_magic;
    }
    *shift = p - bits;                  // resulting shift

    return result_magic;
}


bool Compiler::fgShouldUseMagicNumberDivide(GenTreeOp* tree)
{
#ifdef _TARGET_ARM64_
    // TODO-ARM64-NYI: We don't have a 'mulHi' implementation yet for ARM64
    return false;
#else

    // During the optOptimizeValnumCSEs phase we can call fgMorph and when we do,
    // if this method returns true we will introduce a new LclVar and
    // a couple of new GenTree nodes, including an assignment to the new LclVar.
    // None of these new GenTree nodes will have valid ValueNumbers. 
    // That is an invalid state for a GenTree node during the optOptimizeValnumCSEs phase.
    //
    // Also during optAssertionProp when extracting side effects we can assert 
    // during gtBuildCommaList if we have one tree that has Value Numbers
    //  and another one that does not.
    // 
    if (!fgGlobalMorph)
    {
        // We only perform the Magic Number Divide optimization during
        // the initial global morph phase
        return false;
    }

    if (tree->gtFlags & GTF_OVERFLOW)
        return false;

    if (tree->gtOp2->gtOper != GT_CNS_INT && tree->gtOp2->gtOper != GT_CNS_LNG)
        return false;

    ssize_t cons = tree->gtOp2->gtIntConCommon.IconValue();

    if (cons == 0 || cons == -1 || cons == 1)
        return false;

    // codegen will expand these
    if (isPow2(cons))
        return false;

    // someone else will fold this away, so don't make it complicated for them
    if (tree->gtOp1->IsCnsIntOrI())
        return false;

    // There is no technical barrier to handling unsigned, however it is quite rare
    // and more work to support and test
    if (tree->gtFlags & GTF_UNSIGNED)
        return false;

    return true;
#endif
}


// transform x%c -> x-((x/c)*c)

GenTree* Compiler::fgMorphModByConst(GenTreeOp* tree)
{
    assert(fgShouldUseMagicNumberDivide(tree));

    var_types type = tree->gtType;

    GenTree* cns = tree->gtOp2;

    GenTree* numerator = fgMakeMultiUse(&tree->gtOp1);

    tree->SetOper(GT_DIV);

    GenTree* mul = gtNewOperNode(GT_MUL, type, tree, gtCloneExpr(cns));

    GenTree* sub = gtNewOperNode(GT_SUB, type, numerator, mul);

#ifdef DEBUG
    sub->gtFlags |= GTF_MORPHED;
#endif

    return sub;
}

// For ARM64 we don't have a remainder instruction,
// The architecture manual suggests the following transformation to 
// generate code for such operator:
//
// a % b = a - (a / b) * b;
//
// This method will produce the above expression in 'a' and 'b' are
// leaf nodes, otherwise, if any of them is not a leaf it will spill
// its value into a temporary variable, an example:
// (x * 2 - 1) % (y + 1) ->  t1 - (t2 * ( comma(t1 = x * 2 - 1, t1) / comma(t2 = y + 1, t2) ) )
//
GenTree* Compiler::fgMorphModToSubMulDiv(GenTreeOp* tree)
{
#ifndef _TARGET_ARM64_
    assert(!"This should only be called for ARM64");
#endif

    if (tree->OperGet() == GT_MOD)
    {
        tree->SetOper(GT_DIV);
    }
    else  if (tree->OperGet() == GT_UMOD)
    {
        tree->SetOper(GT_UDIV);
    }
    else
    {
        noway_assert(!"Illegal gtOper in fgMorphModToSubMulDiv");
    }

    var_types type = tree->gtType;
    GenTree* denominator = tree->gtOp2;
    GenTree* numerator = tree->gtOp1;

    if (!numerator->OperIsLeaf())
    {
        numerator = fgMakeMultiUse(&tree->gtOp1);
    }

    if (!denominator->OperIsLeaf())
    {
        denominator = fgMakeMultiUse(&tree->gtOp2);
    }

    GenTree* mul = gtNewOperNode(GT_MUL, type, tree, gtCloneExpr(denominator));
    GenTree* sub = gtNewOperNode(GT_SUB, type, gtCloneExpr(numerator), mul);

#ifdef DEBUG
    sub->gtFlags |= GTF_MORPHED;
#endif

    return sub;
}

// Turn a division by a constant into a multiplication by constant + some adjustments
// see comments on GetSignedMagicNumberForDivide for source of this algorithm.
// returns: the transformed tree

GenTree* Compiler::fgMorphDivByConst(GenTreeOp* tree)
{
    assert(fgShouldUseMagicNumberDivide(tree));

    JITDUMP("doing magic number divide optimization\n");

    int64_t   denominator = tree->gtOp2->gtIntConCommon.IconValue();
    int64_t   magic;
    int       shift;
    var_types type = tree->gtType;

    if (tree->gtType == TYP_INT)
    {
        magic = GetSignedMagicNumberForDivide<int32_t>((int32_t) denominator, &shift);
    }
    else
    {
        magic = GetSignedMagicNumberForDivide<int64_t>((int64_t) denominator, &shift);
    }

    GenTree* numerator = nullptr;

    // If signs of the denominator and magic number don't match,
    // we will need to use the numerator again.
    if (signum(denominator) != signum(magic))
    {
        numerator = fgMakeMultiUse(&tree->gtOp1);
        tree->gtFlags |= GTF_ASG;
    }

    if (type == TYP_LONG)
        tree->gtOp2->gtIntConCommon.SetLngValue(magic);
    else
        tree->gtOp2->gtIntConCommon.SetIconValue((ssize_t)magic);

    tree->SetOper(GT_MULHI);
            
    GenTree* t = tree;
    GenTree* mulresult = tree;

    JITDUMP("Multiply Result:\n");
    DISPTREE(mulresult);
            
    GenTree *adjusted = mulresult;

    if (denominator > 0 && magic < 0) 
    {
        // add the numerator back in
        adjusted = gtNewOperNode(GT_ADD, type, mulresult, numerator);
    } 
    else if (denominator < 0 && magic > 0) 
    {
        // subtract the numerator off
        adjusted = gtNewOperNode(GT_SUB, type, mulresult, numerator);
    }
    else
    {
        adjusted = mulresult;
    }

    GenTree* result1 = adjusted;
    if (shift != 0)
    {
        result1 = gtNewOperNode(GT_RSH, type, adjusted, gtNewIconNode(shift, TYP_INT));
    }

    GenTree* secondClone = fgMakeMultiUse(&result1);

    GenTree* result2 = gtNewOperNode(GT_RSZ, type, secondClone, gtNewIconNode(genTypeSize(type) * 8 - 1, type));
            

    GenTree* result = gtNewOperNode(GT_ADD, type, result1, result2);
    JITDUMP("Final Magic Number divide:\n");
    DISPTREE(result);

#ifdef DEBUG
    result->gtFlags |= GTF_MORPHED;
#endif

    return result;
}

//------------------------------------------------------------------------------
// fgOperIsBitwiseRotationRoot : Check if the operation can be a root of a bitwise rotation tree.
//
//
// Arguments:
//    oper  - Operation to check
//
// Return Value:
//    True if the operation can be a root of a bitwise rotation tree; false otherwise.

bool Compiler::fgOperIsBitwiseRotationRoot(genTreeOps oper)
{
    return (oper == GT_OR) || (oper == GT_XOR);
}

//------------------------------------------------------------------------------
// fgRecognizeAndMorphBitwiseRotation : Check if the tree represents a left or right rotation. If so, return
//                                      an equivalent GT_ROL or GT_ROR tree; otherwise, return the original tree.
//
// Arguments:
//    tree  - tree to check for a rotation pattern
//
// Return Value:
//    An equivalent GT_ROL or GT_ROR tree if a pattern is found; original tree otherwise.
//
// Assumption:
//    The input is a GT_OR or a GT_XOR tree.

GenTreePtr Compiler::fgRecognizeAndMorphBitwiseRotation(GenTreePtr tree)
{
#ifndef LEGACY_BACKEND
    //
    // Check for a rotation pattern, e.g.,
    //
    //                         OR                      ROL
    //                      /      \                   / \
        //                    LSH      RSZ      ->        x   y
    //                    / \      / \
        //                   x  AND   x  AND
    //                      / \      / \
        //                     y  31   ADD  31
    //                             / \
        //                            NEG 32
    //                             |
    //                             y
    // The patterns recognized:
    // (x << (y & M)) op (x >>> ((-y + N) & M))
    // (x >>> ((-y + N) & M)) op (x << (y & M))
    //
    // (x << y) op (x >>> (-y + N))
    // (x >> > (-y + N)) op (x << y)
    //
    // (x >>> (y & M)) op (x << ((-y + N) & M))
    // (x << ((-y + N) & M)) op (x >>> (y & M))
    //
    // (x >>> y) op (x << (-y + N))
    // (x << (-y + N)) op (x >>> y)
    //
    // (x << c1) op (x >>> c2)
    // (x >>> c1) op (x << c2)
    //
    // where 
    // c1 and c2 are const
    // c1 + c2 == bitsize(x)
    // N == bitsize(x)
    // M is const
    // M & (N - 1) == N - 1
    // op is either | or ^

    if (((tree->gtFlags & GTF_PERSISTENT_SIDE_EFFECTS) != 0) ||
        ((tree->gtFlags & GTF_ORDER_SIDEEFF) != 0))
    {
        // We can't do anything if the tree has assignments, calls, or volatile
        // reads. Note that we allow GTF_EXCEPT side effect since any exceptions
        // thrown by the original tree will be thrown by the transformed tree as well.
        return tree;
    }

    genTreeOps      oper = tree->OperGet();
    assert(fgOperIsBitwiseRotationRoot(oper));

    // Check if we have an LSH on one side of the OR and an RSZ on the other side.
    GenTreePtr op1 = tree->gtGetOp1();
    GenTreePtr op2 = tree->gtGetOp2();
    GenTreePtr leftShiftTree = nullptr;
    GenTreePtr rightShiftTree = nullptr;
    if ((op1->OperGet() == GT_LSH) && (op2->OperGet() == GT_RSZ))
    {
        leftShiftTree = op1;
        rightShiftTree = op2;
    }
    else if ((op1->OperGet() == GT_RSZ) && (op2->OperGet() == GT_LSH))
    {
        leftShiftTree = op2;
        rightShiftTree = op1;
    }
    else
    {
        return tree;
    }

    // Check if the trees representing the value to shift are identical.
    // We already checked that there are no side effects above.
    if (GenTree::Compare(leftShiftTree->gtGetOp1(), rightShiftTree->gtGetOp1()))
    {
        GenTreePtr rotatedValue = leftShiftTree->gtGetOp1();
        var_types rotatedValueActualType = genActualType(rotatedValue->gtType);
        ssize_t rotatedValueBitSize = genTypeSize(rotatedValueActualType) * 8;
        noway_assert((rotatedValueBitSize == 32) || (rotatedValueBitSize == 64));
        GenTreePtr leftShiftIndex = leftShiftTree->gtGetOp2();
        GenTreePtr rightShiftIndex = rightShiftTree->gtGetOp2();

        // The shift index may be masked. At least (rotatedValueBitSize - 1) lower bits
        // shouldn't be masked for the transformation to be valid. If additional
        // higher bits are not masked, the transformation is still valid since the result
        // of MSIL shift instructions is unspecified if the shift amount is greater or equal
        // than the width of the value being shifted.
        ssize_t minimalMask = rotatedValueBitSize - 1;
        ssize_t leftShiftMask = -1;
        ssize_t rightShiftMask = -1;

        if ((leftShiftIndex->OperGet() == GT_AND))
        {
            if (leftShiftIndex->gtGetOp2()->IsCnsIntOrI())
            {
                leftShiftMask = leftShiftIndex->gtGetOp2()->gtIntCon.gtIconVal;
                leftShiftIndex = leftShiftIndex->gtGetOp1();
            }
            else
            {
                return tree;
            }
        }

        if ((rightShiftIndex->OperGet() == GT_AND))
        {
            if (rightShiftIndex->gtGetOp2()->IsCnsIntOrI())
            {
                rightShiftMask = rightShiftIndex->gtGetOp2()->gtIntCon.gtIconVal;
                rightShiftIndex = rightShiftIndex->gtGetOp1();
            }
            else
            {
                return tree;
            }
        }

        if (((minimalMask & leftShiftMask) != minimalMask) ||
            ((minimalMask & rightShiftMask) != minimalMask))
        {
            // The shift index is overmasked, e.g., we have
            // something like (x << y & 15) or
            // (x >> (32 - y) & 15 with 32 bit x.
            // The transformation is not valid.
            return tree;
        }

        GenTreePtr shiftIndexWithAdd = nullptr;
        GenTreePtr shiftIndexWithoutAdd = nullptr;
        genTreeOps rotateOp = GT_NONE;
        GenTreePtr rotateIndex = nullptr;

        if (leftShiftIndex->OperGet() == GT_ADD)
        {
            shiftIndexWithAdd = leftShiftIndex;
            shiftIndexWithoutAdd = rightShiftIndex;
            rotateOp = GT_ROR;
        }
        else if (rightShiftIndex->OperGet() == GT_ADD)
        {
            shiftIndexWithAdd = rightShiftIndex;
            shiftIndexWithoutAdd = leftShiftIndex;
            rotateOp = GT_ROL;
        }

        if (shiftIndexWithAdd != nullptr)
        {
            if (shiftIndexWithAdd->gtGetOp2()->IsCnsIntOrI())
            {
                if (shiftIndexWithAdd->gtGetOp2()->gtIntCon.gtIconVal == rotatedValueBitSize)
                {
                    if (shiftIndexWithAdd->gtGetOp1()->OperGet() == GT_NEG)
                    {
                        if (GenTree::Compare(shiftIndexWithAdd->gtGetOp1()->gtGetOp1(), shiftIndexWithoutAdd))
                        {
                            // We found one of these patterns:
                            // (x << (y & M)) | (x >>> ((-y + N) & M))
                            // (x << y) | (x >>> (-y + N))
                            // (x >>> (y & M)) | (x << ((-y + N) & M))
                            // (x >>> y) | (x << (-y + N))
                            // where N == bitsize(x), M is const, and
                            // M & (N - 1) == N - 1

#ifndef _TARGET_64BIT_
                            if (!shiftIndexWithoutAdd->IsCnsIntOrI() && (rotatedValueBitSize == 64))
                            {
                                // TODO: we need to handle variable-sized long shifts specially on x86.
                                // GT_LSH, GT_RSH, and GT_RSZ have helpers for this case. We may need
                                // to add helpers for GT_ROL and GT_ROR.
                                NYI("Rotation of a long value by variable amount");
                            }
#endif

                            rotateIndex = shiftIndexWithoutAdd;
                        }
                    }
                }
            }
        }
        else if ((leftShiftIndex->IsCnsIntOrI() &&
                  rightShiftIndex->IsCnsIntOrI()))
        {
            if (leftShiftIndex->gtIntCon.gtIconVal +
                rightShiftIndex->gtIntCon.gtIconVal == rotatedValueBitSize)
            {
                // We found this pattern:
                // (x << c1) | (x >>> c2)
                // where c1 and c2 are const and c1 + c2 == bitsize(x)
                rotateOp = GT_ROL;
                rotateIndex = leftShiftIndex;
            }
        }

        if (rotateIndex != nullptr)
        {
            noway_assert(GenTree::OperIsRotate(rotateOp));

            unsigned inputTreeEffects = tree->gtFlags & GTF_ALL_EFFECT;

            // We can use the same tree only during global morph; reusing the tree in a later morph
            // may invalidate value numbers.
            if (fgGlobalMorph)
            {
                tree->gtOp.gtOp1 = rotatedValue;
                tree->gtOp.gtOp2 = rotateIndex;
                tree->ChangeOper(rotateOp);
                noway_assert(inputTreeEffects == ((rotatedValue->gtFlags | rotateIndex->gtFlags) & GTF_ALL_EFFECT));
            }
            else
            {
                tree = gtNewOperNode(rotateOp, rotatedValueActualType, rotatedValue, rotateIndex);
                noway_assert(inputTreeEffects == (tree->gtFlags & GTF_ALL_EFFECT));
            }

            return tree;
        }
    }
#endif //LEGACY_BACKEND
    return tree;
}

#if !CPU_HAS_FP_SUPPORT
GenTreePtr Compiler::fgMorphToEmulatedFP(GenTreePtr tree)
{

    genTreeOps      oper    = tree->OperGet();
    var_types       typ     = tree->TypeGet();
    GenTreePtr      op1     = tree->gtOp.gtOp1;
    GenTreePtr      op2     = tree->gtGetOp2();

    /*
        We have to use helper calls for all FP operations:

            FP operators that operate on FP values
            casts to and from FP
            comparisons of FP values
     */

    if  (varTypeIsFloating(typ) || (op1 && varTypeIsFloating(op1->TypeGet())))
    {
        int         helper;
        GenTreePtr  args;
        size_t      argc = genTypeStSz(typ);

        /* Not all FP operations need helper calls */

        switch (oper)
        {
        case GT_ASG:
        case GT_IND:
        case GT_LIST:
        case GT_ADDR:
        case GT_COMMA:
            return tree;
        }

#ifdef DEBUG

        /* If the result isn't FP, it better be a compare or cast */

        if  (!(varTypeIsFloating(typ) ||
               tree->OperIsCompare()  || oper == GT_CAST))
            gtDispTree(tree);

        noway_assert(varTypeIsFloating(typ) ||
               tree->OperIsCompare()  || oper == GT_CAST);
#endif

        /* Keep track of how many arguments we're passing */

        fgPtrArgCntCur += argc;

        /* Is this a binary operator? */

        if  (op2)
        {
            /* Add the second operand to the argument count */

            fgPtrArgCntCur += argc; argc *= 2;

            /* What kind of an operator do we have? */

            switch (oper)
            {
            case GT_ADD: helper = CPX_R4_ADD; break;
            case GT_SUB: helper = CPX_R4_SUB; break;
            case GT_MUL: helper = CPX_R4_MUL; break;
            case GT_DIV: helper = CPX_R4_DIV; break;
//              case GT_MOD: helper = CPX_R4_REM; break;

            case GT_EQ : helper = CPX_R4_EQ ; break;
            case GT_NE : helper = CPX_R4_NE ; break;
            case GT_LT : helper = CPX_R4_LT ; break;
            case GT_LE : helper = CPX_R4_LE ; break;
            case GT_GE : helper = CPX_R4_GE ; break;
            case GT_GT : helper = CPX_R4_GT ; break;

            default:
#ifdef DEBUG
                gtDispTree(tree);
#endif
                noway_assert(!"unexpected FP binary op");
                break;
            }

            args = gtNewArgList(tree->gtOp.gtOp2, tree->gtOp.gtOp1);
        }
        else
        {
            switch (oper)
            {
            case GT_RETURN:
                return tree;

            case GT_CAST:
                noway_assert(!"FP cast");

            case GT_NEG: helper = CPX_R4_NEG; break;

            default:
#ifdef DEBUG
                gtDispTree(tree);
#endif
                noway_assert(!"unexpected FP unary op");
                break;
            }

            args = gtNewArgList(tree->gtOp.gtOp1);
        }

        /* If we have double result/operands, modify the helper */

        if  (typ == TYP_DOUBLE)
        {
            noway_assert(CPX_R4_NEG+1 == CPX_R8_NEG);
            noway_assert(CPX_R4_ADD+1 == CPX_R8_ADD);
            noway_assert(CPX_R4_SUB+1 == CPX_R8_SUB);
            noway_assert(CPX_R4_MUL+1 == CPX_R8_MUL);
            noway_assert(CPX_R4_DIV+1 == CPX_R8_DIV);

            helper++;
        }
        else
        {
            noway_assert(tree->OperIsCompare());

            noway_assert(CPX_R4_EQ+1 == CPX_R8_EQ);
            noway_assert(CPX_R4_NE+1 == CPX_R8_NE);
            noway_assert(CPX_R4_LT+1 == CPX_R8_LT);
            noway_assert(CPX_R4_LE+1 == CPX_R8_LE);
            noway_assert(CPX_R4_GE+1 == CPX_R8_GE);
            noway_assert(CPX_R4_GT+1 == CPX_R8_GT);
        }

        tree = fgMorphIntoHelperCall(tree, helper, args);

        if  (fgPtrArgCntMax < fgPtrArgCntCur)
            fgPtrArgCntMax = fgPtrArgCntCur;

        fgPtrArgCntCur -= argc;
        return tree;

    case GT_RETURN:

        if  (op1)
        {

            if  (compCurBB == genReturnBB)
            {
                /* This is the 'exitCrit' call at the exit label */

                noway_assert(op1->gtType == TYP_VOID);
                noway_assert(op2 == 0);

                tree->gtOp.gtOp1 = op1 = fgMorphTree(op1);

                return tree;
            }

            /* This is a (real) return value -- check its type */

#ifdef DEBUG
            if (genActualType(op1->TypeGet()) != genActualType(info.compRetType))
            {
                bool allowMismatch = false;

                // Allow TYP_BYREF to be returned as TYP_I_IMPL and vice versa
                if ((info.compRetType == TYP_BYREF &&
                     genActualType(op1->TypeGet()) == TYP_I_IMPL) ||
                    (op1->TypeGet() == TYP_BYREF &&
                     genActualType(info.compRetType) == TYP_I_IMPL))
                    allowMismatch = true;

                if (varTypeIsFloating(info.compRetType) && varTypeIsFloating(op1->TypeGet()))
                    allowMismatch = true;

                if (!allowMismatch)
                    NO_WAY("Return type mismatch");
            }
#endif
        }
        break;

    }
    return tree;
}
#endif

/*****************************************************************************
 *
 *  Transform the given tree for code generation and return an equivalent tree.
 */


GenTreePtr          Compiler::fgMorphTree(GenTreePtr tree, MorphAddrContext* mac)
{
    noway_assert(tree);
    noway_assert(tree->gtOper != GT_STMT);

#ifdef DEBUG
    if (verbose)
    {
        if ((unsigned)JitConfig.JitBreakMorphTree() == tree->gtTreeID)
        {
            noway_assert(!"JitBreakMorphTree hit");
        }
    }
#endif

#ifdef DEBUG
    int thisMorphNum = 0;
    if (verbose && treesBeforeAfterMorph)
    {
        thisMorphNum = morphNum++;
        printf("\nfgMorphTree (before %d):\n", thisMorphNum);
        gtDispTree(tree);
    }
#endif

    /*-------------------------------------------------------------------------
     * fgMorphTree() can potentially replace a tree with another, and the
     * caller has to store the return value correctly.
     * Turn this on to always make copy of "tree" here to shake out
     * hidden/unupdated references.
     */

#ifdef DEBUG

    if  (compStressCompile(STRESS_GENERIC_CHECK, 0))
    {
        GenTreePtr      copy;

#ifdef SMALL_TREE_NODES
        if  (GenTree::s_gtNodeSizes[tree->gtOper] == TREE_NODE_SZ_SMALL)
        {
            copy = gtNewLargeOperNode(GT_ADD, TYP_INT);
        }
        else
#endif
        {
            copy = new (this, GT_CALL) GenTreeCall(TYP_INT);
        }

        copy->CopyFrom(tree, this);

#if defined (LATE_DISASM)
        // GT_CNS_INT is considered small, so CopyFrom() won't copy all fields
        if  ((tree->gtOper == GT_CNS_INT) && tree->IsIconHandle())
        {
            copy->gtIntCon.gtIconHdl.gtIconHdl1 = tree->gtIntCon.gtIconHdl.gtIconHdl1;
            copy->gtIntCon.gtIconHdl.gtIconHdl2 = tree->gtIntCon.gtIconHdl.gtIconHdl2;
        }
#endif

        DEBUG_DESTROY_NODE(tree);
        tree = copy;
    }
#endif // DEBUG

    if (fgGlobalMorph)
    {
        /* Ensure that we haven't morphed this node already */
        assert(((tree->gtFlags & GTF_MORPHED) == 0) && "ERROR: Already morphed this node!");

#if LOCAL_ASSERTION_PROP
        /* Before morphing the tree, we try to propagate any active assertions */
        if (optLocalAssertionProp)
        {
            /* Do we have any active assertions? */

            if (optAssertionCount > 0)
            {
                GenTreePtr newTree = tree;
                while (newTree != NULL)
                {
                    tree = newTree;
                    /* newTree is non-Null if we propagated an assertion */
                    newTree = optAssertionProp(apFull, tree, NULL);
                }
                noway_assert(tree != NULL);
            }
        }
        PREFAST_ASSUME(tree != NULL);
#endif
    }

    /* Save the original un-morphed tree for fgMorphTreeDone */

    GenTreePtr oldTree = tree;

    /* Figure out what kind of a node we have */

    unsigned kind = tree->OperKind();

    /* Is this a constant node? */

    if  (kind & GTK_CONST)
    {
        tree = fgMorphConst(tree);
        goto DONE;
    }

    /* Is this a leaf node? */

    if  (kind & GTK_LEAF)
    {
        tree = fgMorphLeaf(tree);
        goto DONE;
    }

    /* Is it a 'simple' unary/binary operator? */

    if  (kind & GTK_SMPOP)
    {
        tree = fgMorphSmpOp(tree, mac);
        goto DONE;
    }

    /* See what kind of a special operator we have here */

    switch  (tree->OperGet())
    {
    case GT_FIELD:
        tree = fgMorphField(tree, mac);
        break;

    case GT_CALL:
        tree = fgMorphCall(tree->AsCall());
        break;

    case GT_ARR_BOUNDS_CHECK:
#ifdef FEATURE_SIMD
    case GT_SIMD_CHK:
#endif // FEATURE_SIMD
        {
            fgSetRngChkTarget(tree);

            GenTreeBoundsChk* bndsChk = tree->AsBoundsChk();
            bndsChk->gtArrLen = fgMorphTree(bndsChk->gtArrLen);
            bndsChk->gtIndex = fgMorphTree(bndsChk->gtIndex);
            // If the index is a comma(throw, x), just return that.
            if (!optValnumCSE_phase && fgIsCommaThrow(bndsChk->gtIndex))
            {
                tree = bndsChk->gtIndex;
            }

            // Propagate effects flags upwards
            bndsChk->gtFlags |= (bndsChk->gtArrLen->gtFlags & GTF_ALL_EFFECT);
            bndsChk->gtFlags |= (bndsChk->gtIndex->gtFlags  & GTF_ALL_EFFECT);

            // Otherwise, we don't change the tree.
        }
        break;

    case GT_ARR_ELEM:
        tree->gtArrElem.gtArrObj        = fgMorphTree(tree->gtArrElem.gtArrObj);
        tree->gtFlags |= tree->gtArrElem.gtArrObj->gtFlags & GTF_ALL_EFFECT;

        unsigned dim;
        for (dim = 0; dim < tree->gtArrElem.gtArrRank; dim++)
        {
            tree->gtArrElem.gtArrInds[dim] = fgMorphTree(tree->gtArrElem.gtArrInds[dim]);
            tree->gtFlags |= tree->gtArrElem.gtArrInds[dim]->gtFlags & GTF_ALL_EFFECT;
        }
        if (fgGlobalMorph)
            fgSetRngChkTarget(tree, false);
        break;

    case GT_ARR_OFFSET:
        tree->gtArrOffs.gtOffset   = fgMorphTree(tree->gtArrOffs.gtOffset);
        tree->gtFlags |= tree->gtArrOffs.gtOffset->gtFlags & GTF_ALL_EFFECT;
        tree->gtArrOffs.gtIndex        = fgMorphTree(tree->gtArrOffs.gtIndex);
        tree->gtFlags |= tree->gtArrOffs.gtIndex->gtFlags & GTF_ALL_EFFECT;
        tree->gtArrOffs.gtArrObj       = fgMorphTree(tree->gtArrOffs.gtArrObj);
        tree->gtFlags |= tree->gtArrOffs.gtArrObj->gtFlags & GTF_ALL_EFFECT;
        if (fgGlobalMorph)
            fgSetRngChkTarget(tree, false);
        break;

    case GT_CMPXCHG:
        tree->gtCmpXchg.gtOpLocation  = fgMorphTree(tree->gtCmpXchg.gtOpLocation);
        tree->gtCmpXchg.gtOpValue     = fgMorphTree(tree->gtCmpXchg.gtOpValue);
        tree->gtCmpXchg.gtOpComparand = fgMorphTree(tree->gtCmpXchg.gtOpComparand);
        break;

    default:
#ifdef DEBUG
        gtDispTree(tree);
#endif
        noway_assert(!"unexpected operator");
    }
DONE:

    fgMorphTreeDone(tree, oldTree DEBUGARG(thisMorphNum));

    return tree;
}


#if LOCAL_ASSERTION_PROP
/*****************************************************************************
 *
 *  Kill all dependent assertions with regard to lclNum.
 *
 */

void                Compiler::fgKillDependentAssertions(unsigned lclNum
                                                        DEBUGARG(GenTreePtr tree))
{
    LclVarDsc * varDsc = &lvaTable[lclNum];

    if (varDsc->lvPromoted)
    {
        noway_assert(varTypeIsStruct(varDsc));

        // Kill the field locals.
        for (unsigned i = varDsc->lvFieldLclStart; i < varDsc->lvFieldLclStart + varDsc->lvFieldCnt; ++i)
        {
            fgKillDependentAssertions(i DEBUGARG(tree));
        }

        // Fall through to kill the struct local itself.
    }

    /* All dependent assertions are killed here */

    ASSERT_TP killed = BitVecOps::MakeCopy(apTraits, GetAssertionDep(lclNum));

    if (killed)
    {
        AssertionIndex   index = optAssertionCount;
        while (killed && (index > 0))
        {
            if  (BitVecOps::IsMember(apTraits, killed, index - 1))
            {
#ifdef DEBUG
                AssertionDsc* curAssertion = optGetAssertion(index);
                noway_assert((curAssertion->op1.lcl.lclNum  == lclNum)     ||
                             ((curAssertion->op2.kind   == O2K_LCLVAR_COPY) &&
                              (curAssertion->op2.lcl.lclNum == lclNum)));
                if (verbose)
                {
                    printf("\nThe assignment ");
                    printTreeID(tree);
                    printf(" using V%02u removes: ", curAssertion->op1.lcl.lclNum);
                    optPrintAssertion(curAssertion);
                }
#endif
                // Remove this bit from the killed mask
                BitVecOps::RemoveElemD(apTraits, killed, index - 1);

                optAssertionRemove(index);
            }

            index--;
        }

        // killed mask should now be zero
        noway_assert(BitVecOps::IsEmpty(apTraits, killed));
    }
}
#endif // LOCAL_ASSERTION_PROP


/*****************************************************************************
 *
 *  This function is called to complete the morphing of a tree node
 *  It should only be called once for each node.
 *  If DEBUG is defined the flag GTF_MORPHED is checked and updated,
 *  to enforce the invariant that each node is only morphed once.
 *  If LOCAL_ASSERTION_PROP is enabled the result tree may be replaced
 *  by an equivalent tree.
 *
 */

void                Compiler::fgMorphTreeDone(GenTreePtr tree,
                                              GenTreePtr oldTree /* == NULL */
                                              DEBUGARG(int morphNum))
{
#ifdef DEBUG
    if (verbose && treesBeforeAfterMorph)
    {
        printf("\nfgMorphTree (after %d):\n", morphNum);
        gtDispTree(tree);
        printf("");         // in our logic this causes a flush
    }
#endif

    if (!fgGlobalMorph)
        return;

    if ((oldTree != NULL) && (oldTree != tree))
    {
        /* Ensure that we have morphed this node */
        assert((tree->gtFlags & GTF_MORPHED) && "ERROR: Did not morph this node!");

#ifdef DEBUG
        TransferTestDataToNode(oldTree, tree);
#endif
    }
    else
    {
        // Ensure that we haven't morphed this node already 
        assert(((tree->gtFlags & GTF_MORPHED) == 0) && "ERROR: Already morphed this node!");
    }

    if (tree->OperKind() & GTK_CONST)
        goto DONE;

#if LOCAL_ASSERTION_PROP

    if (!optLocalAssertionProp)
        goto DONE;

    /* Do we have any active assertions? */

    if (optAssertionCount > 0)
    {
        /* Is this an assignment to a local variable */

        if ((tree->OperKind() & GTK_ASGOP) &&
            (tree->gtOp.gtOp1->gtOper == GT_LCL_VAR || tree->gtOp.gtOp1->gtOper == GT_LCL_FLD))
        {
            unsigned op1LclNum = tree->gtOp.gtOp1->gtLclVarCommon.gtLclNum; noway_assert(op1LclNum  < lvaCount);
            fgKillDependentAssertions(op1LclNum DEBUGARG(tree));
        }
    }

    /* If this tree makes a new assertion - make it available */
    optAssertionGen(tree);

#endif // LOCAL_ASSERTION_PROP

DONE:;

#ifdef DEBUG
    /* Mark this node as being morphed */
    tree->gtFlags |= GTF_MORPHED;
#endif
}


/*****************************************************************************
 *
 *  Check and fold blocks of type BBJ_COND and BBJ_SWITCH on constants
 *  Returns true if we modified the flow graph
 */

bool                Compiler::fgFoldConditional(BasicBlock * block)
{
    bool result = false;

    // We don't want to make any code unreachable
    if (opts.compDbgCode || opts.MinOpts())
      return false;

    if (block->bbJumpKind == BBJ_COND)
    {
        noway_assert(block->bbTreeList && block->bbTreeList->gtPrev);

        GenTreePtr stmt = block->bbTreeList->gtPrev;

        noway_assert(stmt->gtNext == NULL);

        if (stmt->gtStmt.gtStmtExpr->gtOper == GT_CALL)
        {
            noway_assert(fgRemoveRestOfBlock);

            /* Unconditional throw - transform the basic block into a BBJ_THROW */
            fgConvertBBToThrowBB(block);

            /* Remove 'block' from the predecessor list of 'block->bbNext' */
            fgRemoveRefPred(block->bbNext, block);

            /* Remove 'block' from the predecessor list of 'block->bbJumpDest' */
            fgRemoveRefPred(block->bbJumpDest, block);

#ifdef DEBUG
            if  (verbose)
            {
                printf("\nConditional folded at BB%02u\n", block->bbNum);
                printf("BB%02u becomes a BBJ_THROW\n", block->bbNum);
            }
#endif
            goto DONE_COND;
        }

        noway_assert(stmt->gtStmt.gtStmtExpr->gtOper == GT_JTRUE);

        /* Did we fold the conditional */

        noway_assert(stmt->gtStmt.gtStmtExpr->gtOp.gtOp1);
        GenTreePtr  cond; cond = stmt->gtStmt.gtStmtExpr->gtOp.gtOp1;

        if (cond->OperKind() & GTK_CONST)
        {
            /* Yupee - we folded the conditional!
             * Remove the conditional statement */

            noway_assert(cond->gtOper == GT_CNS_INT);
            noway_assert((block->bbNext->countOfInEdges()     > 0) &&
                         (block->bbJumpDest->countOfInEdges() > 0));

            /* remove the statement from bbTreelist - No need to update
             * the reference counts since there are no lcl vars */
            fgRemoveStmt(block, stmt);

            // block is a BBJ_COND that we are folding the conditional for
            // bTaken is the path that will always be taken from block
            // bNotTaken is the path that will never be taken from block
            //
            BasicBlock * bTaken;
            BasicBlock * bNotTaken;

            if (cond->gtIntCon.gtIconVal != 0)
            {
                /* JTRUE 1 - transform the basic block into a BBJ_ALWAYS */
                block->bbJumpKind = BBJ_ALWAYS;
                bTaken    = block->bbJumpDest;
                bNotTaken = block->bbNext;
            }
            else
            {
                /* Unmark the loop if we are removing a backwards branch */
                /* dest block must also be marked as a loop head and     */
                /* We must be able to reach the backedge block           */
                if ((block->bbJumpDest->isLoopHead())          &&
                    (block->bbJumpDest->bbNum <= block->bbNum) &&
                    fgReachable(block->bbJumpDest, block))
                {
                    optUnmarkLoopBlocks(block->bbJumpDest, block);
                }

                /* JTRUE 0 - transform the basic block into a BBJ_NONE   */
                block->bbJumpKind = BBJ_NONE;
                noway_assert(!(block->bbFlags & BBF_NEEDS_GCPOLL));
                bTaken    = block->bbNext;
                bNotTaken = block->bbJumpDest;
            }

            if (fgHaveValidEdgeWeights)
            {
                // We are removing an edge from block to bNotTaken
                // and we have already computed the edge weights, so
                // we will try to adjust some of the weights
                //
                flowList *    edgeTaken = fgGetPredForBlock(bTaken, block);
                BasicBlock *  bUpdated  = NULL;  // non-NULL if we updated the weight of an internal block

                // We examine the taken edge (block -> bTaken)
                // if block has valid profile weight and bTaken does not we try to adjust bTaken's weight
                // else if bTaken has valid profile weight and block does not we try to adjust block's weight
                // We can only adjust the block weights when (the edge block -> bTaken) is the only edge into bTaken
                //
                if (block->bbFlags & BBF_PROF_WEIGHT)
                {
                    // The edge weights for (block -> bTaken) are 100% of block's weight
                    edgeTaken->flEdgeWeightMin = block->bbWeight;
                    edgeTaken->flEdgeWeightMax = block->bbWeight;

                    if ((bTaken->bbFlags & BBF_PROF_WEIGHT) == 0)
                    {
                        if ((bTaken->countOfInEdges() == 1) || (bTaken->bbWeight < block->bbWeight))
                        {
                            // Update the weight of bTaken
                            bTaken->inheritWeight(block);
                            bUpdated = bTaken;
                        }
                    }
                }
                else if (bTaken->bbFlags & BBF_PROF_WEIGHT)
                {
                    if (bTaken->countOfInEdges() == 1)
                    {
                        // There is only one in edge to bTaken
                        edgeTaken->flEdgeWeightMin = bTaken->bbWeight;
                        edgeTaken->flEdgeWeightMax = bTaken->bbWeight;

                        // Update the weight of block
                        block->inheritWeight(bTaken);
                        bUpdated = block;
                    }
                }

                if (bUpdated != NULL)
                {
                    flowList * edge;
                    // Now fix the weights of the edges out of 'bUpdated'
                    switch (bUpdated->bbJumpKind) {
                    case BBJ_NONE:
                        edge = fgGetPredForBlock(bUpdated->bbNext, bUpdated);
                        edge->flEdgeWeightMax = bUpdated->bbWeight;
                        break;
                    case BBJ_COND:
                        edge = fgGetPredForBlock(bUpdated->bbNext, bUpdated);
                        edge->flEdgeWeightMax = bUpdated->bbWeight;
                        __fallthrough;
                    case BBJ_ALWAYS:
                        edge = fgGetPredForBlock(bUpdated->bbJumpDest, bUpdated);
                        edge->flEdgeWeightMax = bUpdated->bbWeight;
                        break;
                    default:
                        // We don't handle BBJ_SWITCH
                        break;
                    }
                }

            }

            /* modify the flow graph */

            /* Remove 'block' from the predecessor list of 'bNotTaken' */
            fgRemoveRefPred(bNotTaken, block);

#ifdef DEBUG
            if  (verbose)
            {
                printf("\nConditional folded at BB%02u\n", block->bbNum);
                printf("BB%02u becomes a %s", block->bbNum,
                       block->bbJumpKind == BBJ_ALWAYS ? "BBJ_ALWAYS" : "BBJ_NONE");
                if  (block->bbJumpKind == BBJ_ALWAYS)
                    printf(" to BB%02u", block->bbJumpDest->bbNum);
                printf("\n");
            }
#endif

            /* if the block was a loop condition we may have to modify
             * the loop table */

            for (unsigned loopNum = 0; loopNum < optLoopCount; loopNum++)
            {
                /* Some loops may have been already removed by
                 * loop unrolling or conditional folding */

                if (optLoopTable[loopNum].lpFlags & LPFLG_REMOVED)
                    continue;

                /* We are only interested in the loop bottom */

                if  (optLoopTable[loopNum].lpBottom == block)
                {
                    if  (cond->gtIntCon.gtIconVal == 0)
                    {
                        /* This was a bogus loop (condition always false)
                         * Remove the loop from the table */

                        optLoopTable[loopNum].lpFlags |= LPFLG_REMOVED;
#ifdef DEBUG
                        if  (verbose)
                        {
                            printf("Removing loop L%02u (from BB%02u to BB%02u)\n\n",
                                   loopNum,
                                   optLoopTable[loopNum].lpFirst ->bbNum,
                                   optLoopTable[loopNum].lpBottom->bbNum);
                        }
#endif
                    }
                }
            }
DONE_COND:
            result = true;
        }
    }
    else if  (block->bbJumpKind == BBJ_SWITCH)
    {
        noway_assert(block->bbTreeList && block->bbTreeList->gtPrev);

        GenTreePtr stmt = block->bbTreeList->gtPrev;

        noway_assert(stmt->gtNext == NULL);

        if (stmt->gtStmt.gtStmtExpr->gtOper == GT_CALL)
        {
            noway_assert(fgRemoveRestOfBlock);

            /* Unconditional throw - transform the basic block into a BBJ_THROW */
            fgConvertBBToThrowBB(block);

            /* update the flow graph */

            unsigned        jumpCnt   = block->bbJumpSwt->bbsCount;
            BasicBlock * *  jumpTab   = block->bbJumpSwt->bbsDstTab;

            for (unsigned val = 0; val < jumpCnt; val++, jumpTab++)
            {
                BasicBlock *  curJump = *jumpTab;

                /* Remove 'block' from the predecessor list of 'curJump' */
                fgRemoveRefPred(curJump, block);
            }

#ifdef DEBUG
            if  (verbose)
            {
                printf("\nConditional folded at BB%02u\n", block->bbNum);
                printf("BB%02u becomes a BBJ_THROW\n", block->bbNum);

            }
#endif
            goto DONE_SWITCH;
        }

        noway_assert(stmt->gtStmt.gtStmtExpr->gtOper == GT_SWITCH);

        /* Did we fold the conditional */

        noway_assert(stmt->gtStmt.gtStmtExpr->gtOp.gtOp1);
        GenTreePtr  cond; cond = stmt->gtStmt.gtStmtExpr->gtOp.gtOp1;

        if (cond->OperKind() & GTK_CONST)
        {
            /* Yupee - we folded the conditional!
             * Remove the conditional statement */

            noway_assert(cond->gtOper == GT_CNS_INT);

            /* remove the statement from bbTreelist - No need to update
             * the reference counts since there are no lcl vars */
            fgRemoveStmt(block, stmt);

            /* modify the flow graph */

            /* Find the actual jump target */
            unsigned        switchVal; switchVal = (unsigned)cond->gtIntCon.gtIconVal;
            unsigned        jumpCnt;   jumpCnt   = block->bbJumpSwt->bbsCount;
            BasicBlock * *  jumpTab;   jumpTab   = block->bbJumpSwt->bbsDstTab;
            bool            foundVal;  foundVal  = false;

            for (unsigned val = 0; val < jumpCnt; val++, jumpTab++)
            {
                BasicBlock *  curJump = *jumpTab;

                assert (curJump->countOfInEdges() > 0);

                // If val matches switchVal or we are at the last entry and
                // we never found the switch value then set the new jump dest

                if ( (val == switchVal) || (!foundVal && (val == jumpCnt-1)))
                {
                    if (curJump != block->bbNext)
                    {
                        /* transform the basic block into a BBJ_ALWAYS */
                        block->bbJumpKind = BBJ_ALWAYS;
                        block->bbJumpDest = curJump;

                        //if we are jumping backwards, make sure we have a GC Poll.
                        if (curJump->bbNum > block->bbNum)
                            block->bbFlags &= ~BBF_NEEDS_GCPOLL;
                    }
                    else
                    {
                        /* transform the basic block into a BBJ_NONE */
                        block->bbJumpKind = BBJ_NONE;
                        block->bbFlags &= ~BBF_NEEDS_GCPOLL;
                    }
                    foundVal = true;
                }
                else
                {
                    /* Remove 'block' from the predecessor list of 'curJump' */
                    fgRemoveRefPred(curJump, block);
                }
            }
#ifdef DEBUG
            if  (verbose)
            {
                printf("\nConditional folded at BB%02u\n", block->bbNum);
                printf("BB%02u becomes a %s", block->bbNum,
                       block->bbJumpKind == BBJ_ALWAYS ? "BBJ_ALWAYS" : "BBJ_NONE");
                if  (block->bbJumpKind == BBJ_ALWAYS)
                    printf(" to BB%02u", block->bbJumpDest->bbNum);
                printf("\n");
            }
#endif
DONE_SWITCH:
            result = true;
        }
    }
    return result;
}


//*****************************************************************************
//
// Morphs a single statement in a block.
// Can be called anytime, unlike fgMorphStmts() which should only be called once.
//
// Returns true  if 'stmt' was removed from the block.
// Returns false if 'stmt' is still in the block (even if other statements were removed).
//

bool                Compiler::fgMorphBlockStmt(BasicBlock * block,
                                               GenTreePtr   stmt
                                      DEBUGARG(const char * msg)  )
{
    noway_assert(stmt->gtOper == GT_STMT);

    compCurBB = block;
    compCurStmt = stmt;

    GenTreePtr morph  = fgMorphTree(stmt->gtStmt.gtStmtExpr);

    // Bug 1106830 - During the CSE phase we can't just remove 
    // morph->gtOp.gtOp2 as it could contain CSE expressions.
    // This leads to a noway_assert in OptCSE.cpp when
    // searching for the removed CSE ref. (using gtFindLink)
    //
    if (!optValnumCSE_phase)
    {
        /* Check for morph as a GT_COMMA with an unconditional throw */
        if (fgIsCommaThrow(morph, true))
        {
#ifdef DEBUG
            if (verbose)
            {
                printf("Folding a top-level fgIsCommaThrow stmt\n");
                printf("Removing op2 as unreachable:\n");
                gtDispTree(morph->gtOp.gtOp2);
                printf("\n");
            }
#endif
            /* Use the call as the new stmt */
            morph = morph->gtOp.gtOp1;
            noway_assert(morph->gtOper == GT_CALL);
        }

        /* we can get a throw as a statement root*/
        if (fgIsThrow(morph))
        {
#ifdef DEBUG
            if (verbose)
            {
                printf("We have a top-level fgIsThrow stmt\n");
                printf("Removing the rest of block as unreachable:\n");
            }
#endif
            noway_assert((morph->gtFlags & GTF_COLON_COND) == 0);
            fgRemoveRestOfBlock = true;
        }
    }

    stmt->gtStmt.gtStmtExpr = morph;

    /* Can the entire tree be removed ? */

    bool removedStmt = fgCheckRemoveStmt(block, stmt);

    /* Or this is the last statement of a conditional branch that was just folded */

    if ((!removedStmt) && (stmt->gtNext == NULL) && !fgRemoveRestOfBlock)
    {
         if (fgFoldConditional(block))
         {
            if (block->bbJumpKind != BBJ_THROW)
                removedStmt = true;
         }
    }

    if (!removedStmt)
    {
        /* Have to re-do the evaluation order since for example
         * some later code does not expect constants as op1 */
        gtSetStmtInfo(stmt);

        /* Have to re-link the nodes for this statement */
        fgSetStmtSeq(stmt);
    }

#ifdef DEBUG
    if (verbose)
    {
        printf("%s %s tree:\n", msg, (removedStmt ? "removed" : "morphed"));
        gtDispTree(morph);
        printf("\n");
    }
#endif

    if (fgRemoveRestOfBlock)
    {
        /* Remove the rest of the stmts in the block */

        while (stmt->gtNext)
        {
            stmt = stmt->gtNext;
            noway_assert(stmt->gtOper == GT_STMT);

            fgRemoveStmt(block, stmt);
        }

        // The rest of block has been removed
        // and we will always throw an exception

        // Update succesors of block
        fgRemoveBlockAsPred(block);

        // For compDbgCode, we prepend an empty BB as the firstBB, it is BBJ_NONE.
        // We should not convert it to a ThrowBB.
        if ((block != fgFirstBB) || ((fgFirstBB->bbFlags & BBF_INTERNAL) == 0) ) {
            // Convert block to a throw bb
            fgConvertBBToThrowBB(block);
        }

#ifdef DEBUG
        if (verbose)
        {
            printf("\n%s Block BB%02u becomes a throw block.\n", msg, block->bbNum);
        }
#endif
        fgRemoveRestOfBlock = false;
    }

    return removedStmt;
}

/*****************************************************************************
 *
 *  Morph the statements of the given block.
 *  This function should be called just once for a block. Use fgMorphBlockStmt()
 *  for reentrant calls.
 */

void                Compiler::fgMorphStmts(BasicBlock * block,
                                           bool * mult, bool * lnot, bool * loadw)
{
    fgRemoveRestOfBlock = false;

    noway_assert(fgExpandInline == false);

    /* Make the current basic block address available globally */

    compCurBB = block;

    *mult = *lnot = *loadw = false;

    fgCurrentlyInUseArgTemps = hashBv::Create(this);

    GenTreePtr stmt, prev;
    for (stmt = block->bbTreeList, prev = NULL;
         stmt;
         prev = stmt->gtStmt.gtStmtExpr,
         stmt = stmt->gtNext)
    {
        noway_assert(stmt->gtOper == GT_STMT);

        if (fgRemoveRestOfBlock)
        {
            fgRemoveStmt(block, stmt);
            continue;
        }
#ifdef FEATURE_SIMD
        if (!opts.MinOpts()                                 &&
            stmt->gtStmt.gtStmtExpr->TypeGet() == TYP_FLOAT &&
            stmt->gtStmt.gtStmtExpr->OperGet() == GT_ASG)
        {
            fgMorphCombineSIMDFieldAssignments(block, stmt);
        }
#endif

        fgMorphStmt      = stmt;
        compCurStmt      = stmt;
        GenTreePtr  tree = stmt->gtStmt.gtStmtExpr;

#ifdef DEBUG
        compCurStmtNum++;
        if (stmt == block->bbTreeList)
            block->bbStmtNum = compCurStmtNum;  // Set the block->bbStmtNum

        unsigned oldHash = verbose ? gtHashValue(tree) : DUMMY_INIT(~0);

        if (verbose)
        {
            printf("\nfgMorphTree BB%02u, stmt %d (before)\n", block->bbNum, compCurStmtNum);
            gtDispTree(tree);
        }
#endif

        /* Morph this statement tree */

        GenTreePtr  morph = fgMorphTree(tree);

        // mark any outgoing arg temps as free so we can reuse them in the next statement.
        
        fgCurrentlyInUseArgTemps->ZeroAll();

        // Has fgMorphStmt been sneakily changed ?

        if (stmt->gtStmt.gtStmtExpr != tree)
        {
            /* This must be tailcall. Ignore 'morph' and carry on with
               the tail-call node */

            morph = stmt->gtStmt.gtStmtExpr;
            noway_assert(compTailCallUsed);
            noway_assert((morph->gtOper == GT_CALL) && morph->AsCall()->IsTailCall());
            noway_assert(stmt->gtNext == NULL);

            GenTreeCall* call = morph->AsCall();
            // Could either be 
            //   - a tail call dispatched via helper in which case block will be ending with BBJ_THROW or
            //   - a fast call made as jmp in which case block will be ending with BBJ_RETURN and marked as containing a jmp.
            noway_assert((call->IsTailCallViaHelper() && (compCurBB->bbJumpKind == BBJ_THROW)) || 
                         (call->IsFastTailCall() && (compCurBB->bbJumpKind == BBJ_RETURN) && (compCurBB->bbFlags &  BBF_HAS_JMP)));
        }
        else if (block != compCurBB)
        {
            /* This must be a tail call that caused a GCPoll to get
               injected.  We haven't actually morphed the call yet
               but the flag still got set, clear it here...  */

#ifdef DEBUG
            tree->gtFlags &= ~GTF_MORPHED;
#endif
            noway_assert(compTailCallUsed);
            noway_assert((tree->gtOper == GT_CALL) && tree->AsCall()->IsTailCall());
            noway_assert(stmt->gtNext == NULL);

            GenTreeCall* call = morph->AsCall();

            // Could either be 
            //   - a tail call dispatched via helper in which case block will be ending with BBJ_THROW or
            //   - a fast call made as jmp in which case block will be ending with BBJ_RETURN and marked as containing a jmp.
            noway_assert((call->IsTailCallViaHelper() && (compCurBB->bbJumpKind == BBJ_THROW)) || 
                         (call->IsFastTailCall() && (compCurBB->bbJumpKind == BBJ_RETURN) && (compCurBB->bbFlags &  BBF_HAS_JMP)));
        }

#ifdef DEBUG
        if (compStressCompile(STRESS_CLONE_EXPR, 30))
        {
            // Clone all the trees to stress gtCloneExpr()

            if (verbose)
            {
                printf("\nfgMorphTree (stressClone from):\n");
                gtDispTree(morph);
            }

            morph = gtCloneExpr(morph);
            noway_assert(morph);

            if (verbose)
            {
                printf("\nfgMorphTree (stressClone to):\n");
                gtDispTree(morph);
            }
        }

        /* If the hash value changes. we modified the tree during morphing */
        if (verbose)
        {
            unsigned newHash = gtHashValue(morph);
            if (newHash != oldHash)
            {
                printf("\nfgMorphTree BB%02u, stmt %d (after)\n", block->bbNum, compCurStmtNum);
                gtDispTree(morph);
            }
        }
#endif

        /* Check for morph as a GT_COMMA with an unconditional throw */
        if (!gtIsActiveCSE_Candidate(morph) && fgIsCommaThrow(morph, true))
        {
            /* Use the call as the new stmt */
            morph = morph->gtOp.gtOp1;
            noway_assert(morph->gtOper == GT_CALL);
            noway_assert((morph->gtFlags & GTF_COLON_COND) == 0);

            fgRemoveRestOfBlock = true;
        }

        stmt->gtStmt.gtStmtExpr = tree = morph;

        noway_assert(fgPtrArgCntCur == 0);

        if (fgRemoveRestOfBlock)
            continue;

        /* Has the statement been optimized away */

        if (fgCheckRemoveStmt(block, stmt))
            continue;

        /* Check if this block ends with a conditional branch that can be folded */

        if (fgFoldConditional(block))
            continue;

        if  (ehBlockHasExnFlowDsc(block))
            continue;

#if OPT_MULT_ADDSUB

        /* Note whether we have two or more +=/-= operators in a row */

        if  (tree->gtOper == GT_ASG_ADD ||
             tree->gtOper == GT_ASG_SUB)
        {
            if  (prev && prev->gtOper == tree->gtOper)
                *mult = true;
        }

#endif

        /* Note "x = a[i] & icon" followed by "x |= a[i] << 8" */

        if  (tree->gtOper == GT_ASG_OR &&
             prev &&
             prev->gtOper == GT_ASG)
        {
            *loadw = true;
        }
    }

    if (fgRemoveRestOfBlock)
    {
        if ((block->bbJumpKind == BBJ_COND) || (block->bbJumpKind == BBJ_SWITCH))
        {
            GenTreePtr first = block->bbTreeList; noway_assert(first);
            GenTreePtr last  = first->gtPrev;     noway_assert(last && last->gtNext == NULL);
            GenTreePtr lastStmt = last->gtStmt.gtStmtExpr;

            if (((block->bbJumpKind == BBJ_COND  ) && (lastStmt->gtOper == GT_JTRUE )) ||
                ((block->bbJumpKind == BBJ_SWITCH) && (lastStmt->gtOper == GT_SWITCH))   )
            {
                GenTreePtr op1  = lastStmt->gtOp.gtOp1;

                if (op1->OperKind() & GTK_RELOP)
                {
                    /* Unmark the comparison node with GTF_RELOP_JMP_USED */
                    op1->gtFlags &= ~GTF_RELOP_JMP_USED;
                }

                last->gtStmt.gtStmtExpr = fgMorphTree(op1);
            }
        }

        /* Mark block as a BBJ_THROW block */
        fgConvertBBToThrowBB(block);
    }

    noway_assert(fgExpandInline == false);

#if FEATURE_FASTTAILCALL
    GenTreePtr recursiveTailCall = nullptr;
    if (block->endsWithTailCallConvertibleToLoop(this, &recursiveTailCall))
    {
        fgMorphRecursiveFastTailCallIntoLoop(block, recursiveTailCall->AsCall());
    }
#endif

#ifdef DEBUG
    compCurBB = (BasicBlock*)INVALID_POINTER_VALUE;
#endif

    // Reset this back so that it doesn't leak out impacting other blocks
    fgRemoveRestOfBlock = false;
}

/*****************************************************************************
 *
 *  Morph the blocks of the method.
 *  Returns true if the basic block list is modified.
 *  This function should be called just once.
 */

void                Compiler::fgMorphBlocks()
{
#ifdef DEBUG
    if  (verbose)
        printf("\n*************** In fgMorphBlocks()\n");
#endif

    /* Since fgMorphTree can be called after various optimizations to re-arrange
     * the nodes we need a global flag to signal if we are during the one-pass
     * global morphing */

    fgGlobalMorph   = true;

#if LOCAL_ASSERTION_PROP
    //
    // Local assertion prop is enabled if we are optimized
    //
    optLocalAssertionProp = (!opts.compDbgCode && !opts.MinOpts());

    if (optLocalAssertionProp)
    {
        //
        // Initialize for local assertion prop
        //
        optAssertionInit(true);
    }
#elif ASSERTION_PROP
    //
    // If LOCAL_ASSERTION_PROP is not set
    // and we have global assertion prop
    // then local assertion prop is always off
    //
    optLocalAssertionProp = false;

#endif

    /*-------------------------------------------------------------------------
     * Process all basic blocks in the function
     */

    BasicBlock *    block       = fgFirstBB; noway_assert(block);

#ifdef DEBUG
    compCurStmtNum = 0;
#endif

    do
    {
#if OPT_MULT_ADDSUB
        bool            mult  = false;
#endif

#if OPT_BOOL_OPS
        bool            lnot  = false;
#endif

        bool            loadw = false;

#ifdef DEBUG
        if (verbose)
            printf("\nMorphing BB%02u of '%s'\n", block->bbNum, info.compFullName);
#endif

#if LOCAL_ASSERTION_PROP
        if (optLocalAssertionProp)
        {
            //
            // Clear out any currently recorded assertion candidates
            // before processing each basic block,
            // also we must  handle QMARK-COLON specially
            //
            optAssertionReset(0);
        }
#endif

        /* Process all statement trees in the basic block */

        GenTreePtr      tree;

        fgMorphStmts(block, &mult, &lnot, &loadw);

#if OPT_MULT_ADDSUB

        if  (mult && (opts.compFlags & CLFLG_TREETRANS) &&
             !opts.compDbgCode && !opts.MinOpts())
        {
            for (tree = block->bbTreeList; tree; tree = tree->gtNext)
            {
                noway_assert(tree->gtOper == GT_STMT);
                GenTreePtr last = tree->gtStmt.gtStmtExpr;

                if  (last->gtOper == GT_ASG_ADD ||
                     last->gtOper == GT_ASG_SUB)
                {
                    GenTreePtr      temp;
                    GenTreePtr      next;

                    GenTreePtr      dst1 = last->gtOp.gtOp1;
                    GenTreePtr      src1 = last->gtOp.gtOp2;

                    if  (!last->IsCnsIntOrI())
                        goto NOT_CAFFE;

                    if  (dst1->gtOper != GT_LCL_VAR)
                        goto NOT_CAFFE;
                    if  (!src1->IsCnsIntOrI())
                        goto NOT_CAFFE;

                    for (;;)
                    {
                        GenTreePtr      dst2;
                        GenTreePtr      src2;

                        /* Look at the next statement */

                        temp = tree->gtNext;
                        if  (!temp)
                            goto NOT_CAFFE;

                        noway_assert(temp->gtOper == GT_STMT);
                        next = temp->gtStmt.gtStmtExpr;

                        if  (next->gtOper != last->gtOper)
                            goto NOT_CAFFE;
                        if  (next->gtType != last->gtType)
                            goto NOT_CAFFE;

                        dst2 = next->gtOp.gtOp1;
                        src2 = next->gtOp.gtOp2;

                        if  (dst2->gtOper != GT_LCL_VAR)
                            goto NOT_CAFFE;
                        if  (dst2->gtLclVarCommon.gtLclNum != dst1->gtLclVarCommon.gtLclNum)
                            goto NOT_CAFFE;

                        if  (!src2->IsCnsIntOrI())
                            goto NOT_CAFFE;

                        if  (last->gtOverflow() != next->gtOverflow())
                            goto NOT_CAFFE;

                        const ssize_t i1 = src1->gtIntCon.gtIconVal;
                        const ssize_t i2 = src2->gtIntCon.gtIconVal;
                        const ssize_t itemp = i1 + i2;

                        /* if the operators are checking for overflow, check for overflow of the operands */

                        if  (next->gtOverflow())
                        {
                            if (next->TypeGet() == TYP_LONG)
                            {
                                if (next->gtFlags & GTF_UNSIGNED)
                                {
                                    ClrSafeInt<UINT64> si1(i1);
                                    if ((si1 + ClrSafeInt<UINT64>(i2)).IsOverflow())
                                        goto NOT_CAFFE;
                                }
                                else
                                {
                                    ClrSafeInt<INT64> si1(i1);
                                    if ((si1 + ClrSafeInt<INT64>(i2)).IsOverflow())
                                        goto NOT_CAFFE;
                                }
                            }
                            else if (next->gtFlags & GTF_UNSIGNED)
                            {
                                ClrSafeInt<UINT32> si1(i1);
                                if ((si1 + ClrSafeInt<UINT32>(i2)).IsOverflow())
                                    goto NOT_CAFFE;
                            }
                            else
                            {
                                ClrSafeInt<INT32> si1(i1);
                                if ((si1 + ClrSafeInt<INT32>(i2)).IsOverflow())
                                    goto NOT_CAFFE;
                            }
                        }

                        /* Fold the two increments/decrements into one */

                        src1->gtIntCon.gtIconVal = itemp;
#ifdef _TARGET_64BIT_
                        if (src1->gtType == TYP_INT)
                        {
                            src1->AsIntCon()->TruncateOrSignExtend32();
                        }
#endif //_TARGET_64BIT_

                        /* Remove the second statement completely */

                        noway_assert(tree->gtNext == temp);
                        noway_assert(temp->gtPrev == tree);

                        if  (temp->gtNext)
                        {
                            noway_assert(temp->gtNext->gtPrev == temp);

                            temp->gtNext->gtPrev = tree;
                            tree->gtNext         = temp->gtNext;
                        }
                        else
                        {
                            tree->gtNext = 0;

                            noway_assert(block->bbTreeList->gtPrev == temp);

                            block->bbTreeList->gtPrev = tree;
                        }
                    }
                }

            NOT_CAFFE:;

            }

        }

#endif

        /* Are we using a single return block? */

        if (block->bbJumpKind == BBJ_RETURN)
        {
             if ((genReturnBB != nullptr)  &&
                 (genReturnBB != block) &&
                 ((block->bbFlags & BBF_HAS_JMP) == 0))
             {
                /* We'll jump to the genReturnBB */

#if !defined(_TARGET_X86_)
                if (info.compFlags & CORINFO_FLG_SYNCH)
                {
                    fgConvertSyncReturnToLeave(block);
                }
                else
#endif // !_TARGET_X86_
                {
                    block->bbJumpKind = BBJ_ALWAYS;
                    block->bbJumpDest = genReturnBB;
                    fgReturnCount--;
                }

                // Note 1: A block is not guaranteed to have a last stmt if its jump kind is BBJ_RETURN.
                // For example a method returning void could have an empty block with jump kind BBJ_RETURN.
                // Such blocks do materialize as part of in-lining.
                //
                // Note 2: A block with jump kind BBJ_RETURN does not necessarily need to end with GT_RETURN.
                // It could end with a tail call or rejected tail call or monitor.exit or a GT_INTRINSIC.
                // For now it is safe to explicitly check whether last stmt is GT_RETURN if genReturnLocal
                // is BAD_VAR_NUM.
                // 
                // TODO: Need to characterize the last top level stmt of a block ending with BBJ_RETURN.

                GenTreePtr last = (block->bbTreeList != nullptr) ? block->bbTreeList->gtPrev : nullptr;
                GenTreePtr ret = (last != nullptr) ? last->gtStmt.gtStmtExpr : nullptr;
                
                //replace the GT_RETURN node to be a GT_ASG that stores the return value into genReturnLocal.
                if (genReturnLocal != BAD_VAR_NUM)
                {
                    // Method must be returning a value other than TYP_VOID.
                    noway_assert(compMethodHasRetVal());

                    // This block must be ending with a GT_RETURN
                    noway_assert(last != nullptr);
                    noway_assert(last->gtOper == GT_STMT);
                    noway_assert(last->gtNext == nullptr);                    
                    noway_assert(ret != nullptr);

                    // GT_RETURN must have non-null operand as the method is returning the value assigned to genReturnLocal
                    noway_assert(ret->OperGet() == GT_RETURN);
                    noway_assert(ret->gtGetOp1() != nullptr);
                    noway_assert(ret->gtGetOp2() == nullptr);

                    last->gtStmt.gtStmtExpr = gtNewTempAssign(genReturnLocal, ret->gtGetOp1());

                    //make sure that copy-prop ignores this assignment.
                    last->gtStmt.gtStmtExpr->gtFlags |= GTF_DONT_CSE;
                }
                else if (ret != nullptr && ret->OperGet() == GT_RETURN)
                {
                    // This block ends with a GT_RETURN
                    noway_assert(last != nullptr);
                    noway_assert(last->gtOper == GT_STMT);
                    noway_assert(last->gtNext == nullptr);
                    
                    // Must be a void GT_RETURN with null operand; delete it as this block branches to oneReturn block
                    noway_assert(ret->TypeGet() == TYP_VOID);
                    noway_assert(ret->gtGetOp1() == nullptr);
                    noway_assert(ret->gtGetOp2() == nullptr);

                    fgRemoveStmt(block, last);
                }

#ifdef DEBUG
                if (verbose)
                {
                    printf("morph BB%02u to point at onereturn.  New block is\n",
                        block->bbNum);
                    fgTableDispBasicBlock(block);
                }
#endif
             }
        }

        block       = block->bbNext;
    }
    while (block);

    /* We are done with the global morphing phase */

    fgGlobalMorph   = false;


#ifdef DEBUG
    if  (verboseTrees)
        fgDispBasicBlocks(true);
#endif

}


/*****************************************************************************
 *
 *  Make some decisions about the kind of code to generate.
 */

void                Compiler::fgSetOptions()
{

    /* Should we force fully interruptible code ? */

#ifdef DEBUG
    if (JitConfig.JitFullyInt() ||
        compStressCompile(STRESS_GENERIC_VARN, 30))
    {
        noway_assert(!codeGen->isGCTypeFixed());
        genInterruptible = true;
    }
#endif

#ifdef DEBUGGING_SUPPORT
    if (opts.compDbgCode)
    {
        assert(!codeGen->isGCTypeFixed());
        genInterruptible = true;        // debugging is easier this way ...
    }
#endif

    /* Assume we won't need an explicit stack frame if this is allowed */


    // CORINFO_HELP_TAILCALL won't work with localloc because of the restoring of
    // the callee-saved registers.
    noway_assert(!compTailCallUsed || !compLocallocUsed);

    if (compLocallocUsed)
        codeGen->setFramePointerRequired(true);

#ifdef _TARGET_X86_

    if (compTailCallUsed)
        codeGen->setFramePointerRequired(true);

#endif // _TARGET_X86_

    if (!opts.genFPopt)
        codeGen->setFramePointerRequired(true);

    // Assert that the EH table has been initialized by now. Note that
    // compHndBBtabAllocCount never decreases; it is a high-water mark
    // of table allocation. In contrast, compHndBBtabCount does shrink
    // if we delete a dead EH region, and if it shrinks to zero, the
    // table pointer compHndBBtab is unreliable.
    assert(compHndBBtabAllocCount >= info.compXcptnsCount);

#ifdef _TARGET_X86_

    // Note: this case, and the !X86 case below, should both use the
    // !X86 path. This would require a few more changes for X86 to use
    // compHndBBtabCount (the current number of EH clauses) instead of
    // info.compXcptnsCount (the number of EH clauses in IL), such as
    // in ehNeedsShadowSPslots(). This is because sometimes the IL has
    // an EH clause that we delete as statically dead code before we
    // get here, leaving no EH clauses left, and thus no requirement
    // to use a frame pointer because of EH. But until all the code uses
    // the same test, leave info.compXcptnsCount here.
    if (info.compXcptnsCount > 0)
        codeGen->setFramePointerRequiredEH(true);

#else // !_TARGET_X86_

    if (compHndBBtabCount > 0)
        codeGen->setFramePointerRequiredEH(true);

#endif // _TARGET_X86_

    //  fpPtrArgCntMax records the maximum number of pushed arguments
    //  Depending upon this value of the maximum number of pushed arguments
    //  we may need to use an EBP frame or be partially interuptible
    //

    if (!compCanEncodePtrArgCntMax())
    {
#ifdef DEBUG
        if (verbose)
            printf("Too many pushed arguments for fully interruptible encoding, marking method as partially interruptible\n");
#endif
        genInterruptible = false;
    }
    if (fgPtrArgCntMax >= sizeof(unsigned))
    {
#ifdef DEBUG
        if (verbose)
            printf("Too many pushed arguments for an ESP based encoding, forcing an EBP frame\n");
#endif
        codeGen->setFramePointerRequiredGCInfo(true);
    }

#if INLINE_NDIRECT
    if (info.compCallUnmanaged)
    {
        codeGen->setFramePointerRequired(true);  // Setup of Pinvoke frame currently requires an EBP style frame
    }
#endif

    if (info.compPublishStubParam)
    {
        codeGen->setFramePointerRequiredGCInfo(true);
    }

    if  (opts.compNeedSecurityCheck)
    {
        codeGen->setFramePointerRequiredGCInfo(true);

#ifndef JIT32_GCENCODER

        // The decoder only reports objects in frames with exceptions if the frame
        // is fully interruptible.
        // Even if there is no catch or other way to resume execution in this frame
        // the VM requires the security object to remain alive until later, so
        // Frames with security objects must be fully interruptible.
        genInterruptible = true;

#endif // JIT32_GCENCODER
    }

    if (compIsProfilerHookNeeded())
    {
        codeGen->setFramePointerRequired(true);
    }

    if (info.compIsVarArgs)
    {
        // Code that initializes lvaVarargsBaseOfStkArgs requires this to be EBP relative.
        codeGen->setFramePointerRequiredGCInfo(true);
    }

    if (lvaReportParamTypeArg())
    {
        codeGen->setFramePointerRequiredGCInfo(true);
    }

//  printf("method will %s be fully interruptible\n", genInterruptible ? "   " : "not");
}


/*****************************************************************************/

GenTreePtr          Compiler::fgInitThisClass()
{
    noway_assert(!compIsForInlining());

    CORINFO_LOOKUP_KIND kind = info.compCompHnd->getLocationOfThisType(info.compMethodHnd);

    if (!kind.needsRuntimeLookup)
    {
        return fgGetSharedCCtor(info.compClassHnd);
    }
    else
    {
        // Collectible types requires that for shared generic code, if we use the generic context paramter
        // that we report it. (This is a conservative approach, we could detect some cases particularly when the
        // context parameter is this that we don't need the eager reporting logic.)
        lvaGenericsContextUsed = true;

        switch (kind.runtimeLookupKind)
        {
        case CORINFO_LOOKUP_THISOBJ :
        // This code takes a this pointer; but we need to pass the static method desc to get the right point in the hierarchy
        {
            GenTreePtr vtTree = gtNewLclvNode(info.compThisArg, TYP_REF);
            // Vtable pointer of this object
            vtTree = gtNewOperNode(GT_IND, TYP_I_IMPL, vtTree);
            vtTree->gtFlags |= GTF_EXCEPT; // Null-pointer exception
            GenTreePtr methodHnd = gtNewIconEmbMethHndNode(info.compMethodHnd);

            return gtNewHelperCallNode(CORINFO_HELP_INITINSTCLASS,
                                       TYP_VOID, 0,
                                       gtNewArgList(vtTree, methodHnd));

        }

        case CORINFO_LOOKUP_CLASSPARAM :
        {
            GenTreePtr vtTree = gtNewLclvNode(info.compTypeCtxtArg, TYP_I_IMPL);
            return gtNewHelperCallNode(CORINFO_HELP_INITCLASS,
                                       TYP_VOID, 0,
                                       gtNewArgList(vtTree));
        }

        case CORINFO_LOOKUP_METHODPARAM :
        {
            GenTreePtr methHndTree = gtNewLclvNode(info.compTypeCtxtArg, TYP_I_IMPL);
            return gtNewHelperCallNode(CORINFO_HELP_INITINSTCLASS,
                                       TYP_VOID, 0,
                                       gtNewArgList(gtNewIconNode(0),methHndTree));
        }
        }

    }

    noway_assert(!"Unknown LOOKUP_KIND");
    UNREACHABLE();
}


#ifdef DEBUG
/*****************************************************************************
 *
 *  Tree walk callback to make sure no GT_QMARK nodes are present in the tree,
 *  except for the allowed ? 1 : 0; pattern.
 */
Compiler::fgWalkResult Compiler::fgAssertNoQmark(GenTreePtr* tree, fgWalkData* data)
{
    if ((*tree)->OperGet() == GT_QMARK)
    {
        fgCheckQmarkAllowedForm(*tree);
    }
    return WALK_CONTINUE;
}

void Compiler::fgCheckQmarkAllowedForm(GenTree* tree)
{
    assert(tree->OperGet() == GT_QMARK);
#ifndef LEGACY_BACKEND
    assert(!"Qmarks beyond morph disallowed.");
#else // LEGACY_BACKEND
    GenTreePtr colon = tree->gtOp.gtOp2;

    assert(colon->gtOp.gtOp1->gtOper == GT_CNS_INT);
    assert(colon->gtOp.gtOp1->AsIntCon()->IconValue() == 0);

    assert(colon->gtOp.gtOp2->gtOper == GT_CNS_INT);
    assert(colon->gtOp.gtOp2->AsIntCon()->IconValue() == 1);
#endif // LEGACY_BACKEND
}

/*****************************************************************************
 *
 *  Verify that the importer has created GT_QMARK nodes in a way we can
 *  process them. The following is allowed:
 *
 *  1. A top level qmark. Top level qmark is of the form:
 *      a) (bool) ? (void) : (void) OR
 *      b) V0N = (bool) ? (type) : (type)
 *
 *  2. Recursion is allowed at the top level, i.e., a GT_QMARK can be a child
 *     of either op1 of colon or op2 of colon but not a child of any other
 *     operator.
 */
void Compiler::fgPreExpandQmarkChecks(GenTreePtr expr)
{
    GenTreePtr topQmark = fgGetTopLevelQmark(expr);

    // If the top level Qmark is null, then scan the tree to make sure
    // there are no qmarks within it.
    if (topQmark == NULL)
    {
        fgWalkTreePre(&expr, Compiler::fgAssertNoQmark, NULL);
    }
    else
    {
        // We could probably expand the cond node also, but don't think the extra effort is necessary,
        // so let's just assert the cond node of a top level qmark doesn't have further top level qmarks.
        fgWalkTreePre(&topQmark->gtOp.gtOp1, Compiler::fgAssertNoQmark, NULL);

        fgPreExpandQmarkChecks(topQmark->gtOp.gtOp2->gtOp.gtOp1);
        fgPreExpandQmarkChecks(topQmark->gtOp.gtOp2->gtOp.gtOp2);
    }
}
#endif // DEBUG

/*****************************************************************************
 *
 *  Get the top level GT_QMARK node in a given "expr", return NULL if such a
 *  node is not present. If the top level GT_QMARK node is assigned to a
 *  GT_LCL_VAR, then return the lcl node in ppDst.
 *
 */
GenTreePtr Compiler::fgGetTopLevelQmark(GenTreePtr expr, GenTreePtr* ppDst /* = NULL */)
{
    if (ppDst != NULL)
    {
        *ppDst = NULL;
    }

    GenTreePtr topQmark = NULL;
    if (expr->gtOper == GT_QMARK)
    {
        topQmark = expr;
    }
    else if (expr->gtOper == GT_ASG &&
             expr->gtOp.gtOp2->gtOper == GT_QMARK &&
             expr->gtOp.gtOp1->gtOper == GT_LCL_VAR)
    {
        topQmark = expr->gtOp.gtOp2;
        if (ppDst != NULL)
        {
            *ppDst = expr->gtOp.gtOp1;
        }
    }
    return topQmark;
}


/*********************************************************************************
 *
 *  For a castclass helper call,
 *  Importer creates the following tree:
 *      tmp = (op1 == null) ? op1 : ((*op1 == (cse = op2, cse)) ? op1 : helper());
 *
 *  This method splits the qmark expression created by the importer into the
 *  following blocks: (block, asg, cond1, cond2, helper, remainder)
 *  Notice that op1 is the result for both the conditions. So we coalesce these
 *  assignments into a single block instead of two blocks resulting a nested diamond.
 *
 *                       +---------->-----------+
 *                       |          |           |
 *                       ^          ^           v
 *                       |          |           |
 *  block-->asg-->cond1--+-->cond2--+-->helper--+-->remainder
 *
 *  We expect to achieve the following codegen:
 *     mov      rsi, rdx                           tmp = op1                  // asgBlock
 *     test     rsi, rsi                           goto skip if tmp == null ? // cond1Block
 *     je       SKIP
 *     mov      rcx, 0x76543210                    cns = op2                  // cond2Block
 *     cmp      qword ptr [rsi], rcx               goto skip if *tmp == op2
 *     je       SKIP
 *     call     CORINFO_HELP_CHKCASTCLASS_SPECIAL  tmp = helper(cns, tmp)     // helperBlock
 *     mov      rsi, rax
 *  SKIP:                                                                     // remainderBlock
 *     tmp has the result.
 *
 */
void Compiler::fgExpandQmarkForCastInstOf(BasicBlock* block, GenTreePtr stmt)
{
#ifdef DEBUG
    if (verbose)
    {
        printf("\nExpanding CastInstOf qmark in BB%02u (before)\n", block->bbNum);
        fgDispBasicBlocks(block, block, true);
    }
#endif // DEBUG

    GenTreePtr expr = stmt->gtStmt.gtStmtExpr;

    GenTreePtr dst = nullptr;
    GenTreePtr qmark = fgGetTopLevelQmark(expr, &dst);
    noway_assert(dst != nullptr);

    assert(qmark->gtFlags & GTF_QMARK_CAST_INSTOF);

    // Get cond, true, false exprs for the qmark.
    GenTreePtr condExpr  = qmark->gtGetOp1();
    GenTreePtr trueExpr  = qmark->gtGetOp2()->AsColon()->ThenNode();
    GenTreePtr falseExpr = qmark->gtGetOp2()->AsColon()->ElseNode();

    // Get cond, true, false exprs for the nested qmark.
    GenTreePtr nestedQmark = falseExpr;
    GenTreePtr cond2Expr;
    GenTreePtr true2Expr;
    GenTreePtr false2Expr;

    if (nestedQmark->gtOper == GT_QMARK)
    {
        cond2Expr  = nestedQmark->gtGetOp1();
        true2Expr  = nestedQmark->gtGetOp2()->AsColon()->ThenNode();
        false2Expr = nestedQmark->gtGetOp2()->AsColon()->ElseNode();

        assert(cond2Expr->gtFlags & GTF_RELOP_QMARK);
        cond2Expr->gtFlags &= ~GTF_RELOP_QMARK;
    }
    else
    {
        // This is a rare case that arises when we are doing minopts and encounter isinst of null
        // gtFoldExpr was still is able to optimize away part of the tree (but not all).
        // That means it does not match our pattern.
        
        // Rather than write code to handle this case, just fake up some nodes to make it match the common 
        // case.  Synthesize a comparison that is always true, and for the result-on-true, use the
        // entire subtree we expected to be the nested question op.

        cond2Expr  = gtNewOperNode(GT_EQ, TYP_INT, gtNewIconNode(0, TYP_I_IMPL), gtNewIconNode(0, TYP_I_IMPL));
        true2Expr  = nestedQmark;
        false2Expr = gtNewIconNode(0, TYP_I_IMPL);
    }
    assert(false2Expr->OperGet() == trueExpr->OperGet());

    // Clear flags as they are now going to be part of JTRUE.
    assert(condExpr->gtFlags  & GTF_RELOP_QMARK);
    condExpr->gtFlags  &= ~GTF_RELOP_QMARK;

    // Create the chain of blocks. See method header comment.
    // The order of blocks after this is the following:
    //     block ... asgBlock ... cond1Block ... cond2Block ... helperBlock ... remainderBlock
    //
    // We need to remember flags that exist on 'block' that we want to propagate to 'remainderBlock',
    // if they are going to be cleared by fgSplitBlockAfterStatement(). We currently only do this only
    // for the GC safe point bit, the logic being that if 'block' was marked gcsafe, then surely
    // remainderBlock will still be GC safe.
    unsigned propagateFlags = block->bbFlags & BBF_GC_SAFE_POINT;
    BasicBlock* remainderBlock = fgSplitBlockAfterStatement(block, stmt);
    fgRemoveRefPred(remainderBlock, block); // We're going to put more blocks between block and remainderBlock.

    BasicBlock* helperBlock    = fgNewBBafter(BBJ_NONE, block, true);
    BasicBlock* cond2Block     = fgNewBBafter(BBJ_COND, block, true);
    BasicBlock* cond1Block     = fgNewBBafter(BBJ_COND, block, true);
    BasicBlock* asgBlock       = fgNewBBafter(BBJ_NONE, block, true);

    remainderBlock->bbFlags |= BBF_JMP_TARGET | BBF_HAS_LABEL | propagateFlags;

    // These blocks are only internal if 'block' is (but they've been set as internal by fgNewBBafter).
    // If they're not internal, mark them as imported to avoid asserts about un-imported blocks.
    if ((block->bbFlags & BBF_INTERNAL) == 0)
    {
        helperBlock->bbFlags &= ~BBF_INTERNAL;
        cond2Block->bbFlags  &= ~BBF_INTERNAL;
        cond1Block->bbFlags  &= ~BBF_INTERNAL;
        asgBlock->bbFlags    &= ~BBF_INTERNAL;
        helperBlock->bbFlags |=  BBF_IMPORTED;
        cond2Block->bbFlags  |=  BBF_IMPORTED;
        cond1Block->bbFlags  |=  BBF_IMPORTED;
        asgBlock->bbFlags    |=  BBF_IMPORTED;
    }

    // Chain the flow correctly.
    fgAddRefPred(asgBlock, block);
    fgAddRefPred(cond1Block, asgBlock);
    fgAddRefPred(cond2Block, cond1Block);
    fgAddRefPred(helperBlock, cond2Block);
    fgAddRefPred(remainderBlock, helperBlock);
    fgAddRefPred(remainderBlock, cond1Block);
    fgAddRefPred(remainderBlock, cond2Block);

    cond1Block->bbJumpDest = remainderBlock;
    cond2Block->bbJumpDest = remainderBlock;

    // Set the weights; some are guesses.
    asgBlock->inheritWeight(block);
    cond1Block->inheritWeight(block);
    cond2Block->inheritWeightPercentage(cond1Block, 50);
    helperBlock->inheritWeightPercentage(cond2Block, 50);

    // Append cond1 as JTRUE to cond1Block
    GenTreePtr jmpTree = gtNewOperNode(GT_JTRUE, TYP_VOID, condExpr);
    GenTreePtr jmpStmt = fgNewStmtFromTree(jmpTree, stmt->gtStmt.gtStmtILoffsx);
    fgInsertStmtAtEnd(cond1Block, jmpStmt);

    // Append cond2 as JTRUE to cond2Block
    jmpTree = gtNewOperNode(GT_JTRUE, TYP_VOID, cond2Expr);
    jmpStmt = fgNewStmtFromTree(jmpTree, stmt->gtStmt.gtStmtILoffsx);
    fgInsertStmtAtEnd(cond2Block, jmpStmt);

    // AsgBlock should get tmp = op1 assignment.
    trueExpr = gtNewTempAssign(dst->AsLclVarCommon()->GetLclNum(), trueExpr);
    GenTreePtr trueStmt = fgNewStmtFromTree(trueExpr, stmt->gtStmt.gtStmtILoffsx);
    fgInsertStmtAtEnd(asgBlock, trueStmt);

    // Since we are adding helper in the JTRUE false path, reverse the cond2 and add the helper.
    gtReverseCond(cond2Expr);
    GenTreePtr helperExpr = gtNewTempAssign(dst->AsLclVarCommon()->GetLclNum(), true2Expr);
    GenTreePtr helperStmt = fgNewStmtFromTree(helperExpr, stmt->gtStmt.gtStmtILoffsx);
    fgInsertStmtAtEnd(helperBlock, helperStmt);

    // Finally remove the nested qmark stmt.
    fgRemoveStmt(block, stmt);

#ifdef DEBUG
    if (verbose)
    {
        printf("\nExpanding CastInstOf qmark in BB%02u (after)\n", block->bbNum);
        fgDispBasicBlocks(block, remainderBlock, true);
    }
#endif // DEBUG
}

/*****************************************************************************
 *
 *  Expand a statement with a top level qmark node. There are three cases, based
 *  on whether the qmark has both "true" and "false" arms, or just one of them.
 *
 *     S0;
 *     C ? T : F;
 *     S1;
 *
 *     Generates ===>
 *
 *                       bbj_always
 *                       +---->------+
 *                 false |           |
 *     S0 -->-- ~C -->-- T   F -->-- S1
 *              |            |
 *              +--->--------+
 *              bbj_cond(true)
 *
 *     -----------------------------------------
 *
 *     S0;
 *     C ? T : NOP;
 *     S1;
 *
 *     Generates ===>
 *
 *                 false
 *     S0 -->-- ~C -->-- T -->-- S1
 *              |                |
 *              +-->-------------+
 *              bbj_cond(true)
 *
 *     -----------------------------------------
 *
 *     S0;
 *     C ? NOP : F;
 *     S1;
 *
 *     Generates ===>
 *
 *                false
 *     S0 -->-- C -->-- F -->-- S1
 *              |               |
 *              +-->------------+
 *              bbj_cond(true)
 *
 *  If the qmark assigns to a variable, then create tmps for "then"
 *  and "else" results and assign the temp to the variable as a writeback step.
 */
void Compiler::fgExpandQmarkStmt(BasicBlock* block, GenTreePtr stmt)
{
    GenTreePtr expr = stmt->gtStmt.gtStmtExpr;

    // Retrieve the Qmark node to be expanded.
    GenTreePtr dst = nullptr;
    GenTreePtr qmark = fgGetTopLevelQmark(expr, &dst);
    if (qmark == nullptr)
    {
        return;
    }

    if (qmark->gtFlags & GTF_QMARK_CAST_INSTOF)
    {
        fgExpandQmarkForCastInstOf(block, stmt);
        return;
    }

#ifdef DEBUG
    if (verbose)
    {
        printf("\nExpanding top-level qmark in BB%02u (before)\n", block->bbNum);
        fgDispBasicBlocks(block, block, true);
    }
#endif // DEBUG

    // Retrieve the operands.
    GenTreePtr condExpr  = qmark->gtGetOp1();
    GenTreePtr trueExpr  = qmark->gtGetOp2()->AsColon()->ThenNode();
    GenTreePtr falseExpr = qmark->gtGetOp2()->AsColon()->ElseNode();

    assert(condExpr->gtFlags & GTF_RELOP_QMARK);
    condExpr->gtFlags &= ~GTF_RELOP_QMARK;

    assert(!varTypeIsFloating(condExpr->TypeGet()));

    bool hasTrueExpr  = (trueExpr->OperGet()  != GT_NOP);
    bool hasFalseExpr = (falseExpr->OperGet() != GT_NOP);
    assert(hasTrueExpr || hasFalseExpr); // We expect to have at least one arm of the qmark!

    // Create remainder, cond and "else" blocks. After this, the blocks are in this order:
    //     block ... condBlock ... elseBlock ... remainderBlock
    //
    // We need to remember flags that exist on 'block' that we want to propagate to 'remainderBlock',
    // if they are going to be cleared by fgSplitBlockAfterStatement(). We currently only do this only
    // for the GC safe point bit, the logic being that if 'block' was marked gcsafe, then surely
    // remainderBlock will still be GC safe.
    unsigned propagateFlags = block->bbFlags & BBF_GC_SAFE_POINT;
    BasicBlock* remainderBlock = fgSplitBlockAfterStatement(block, stmt);
    fgRemoveRefPred(remainderBlock, block); // We're going to put more blocks between block and remainderBlock.

    BasicBlock* condBlock      = fgNewBBafter(BBJ_COND, block, true);
    BasicBlock* elseBlock      = fgNewBBafter(BBJ_NONE, condBlock, true);

    // These blocks are only internal if 'block' is (but they've been set as internal by fgNewBBafter).
    // If they're not internal, mark them as imported to avoid asserts about un-imported blocks.
    if ((block->bbFlags & BBF_INTERNAL) == 0)
    {
        condBlock->bbFlags &= ~BBF_INTERNAL;
        elseBlock->bbFlags &= ~BBF_INTERNAL;
        condBlock->bbFlags |=  BBF_IMPORTED;
        elseBlock->bbFlags |=  BBF_IMPORTED;
    }

    remainderBlock->bbFlags |= BBF_JMP_TARGET | BBF_HAS_LABEL | propagateFlags;

    condBlock->inheritWeight(block);

    fgAddRefPred(condBlock, block);
    fgAddRefPred(elseBlock, condBlock);
    fgAddRefPred(remainderBlock, elseBlock);

    BasicBlock* thenBlock = nullptr;
    if (hasTrueExpr && hasFalseExpr)
    {
        //                       bbj_always
        //                       +---->------+
        //                 false |           |
        //     S0 -->-- ~C -->-- T   F -->-- S1
        //              |            |
        //              +--->--------+
        //              bbj_cond(true)
        //
        gtReverseCond(condExpr);
        condBlock->bbJumpDest = elseBlock;

        thenBlock = fgNewBBafter(BBJ_ALWAYS, condBlock, true);
        thenBlock->bbJumpDest = remainderBlock;
        if ((block->bbFlags & BBF_INTERNAL) == 0)
        {
            thenBlock->bbFlags &= ~BBF_INTERNAL;
            thenBlock->bbFlags |=  BBF_IMPORTED;
        }

        elseBlock->bbFlags |= (BBF_JMP_TARGET | BBF_HAS_LABEL);

        fgAddRefPred(thenBlock, condBlock);
        fgAddRefPred(remainderBlock, thenBlock);

        thenBlock->inheritWeightPercentage(condBlock, 50);
        elseBlock->inheritWeightPercentage(condBlock, 50);
    }
    else if (hasTrueExpr)
    {
        //                 false
        //     S0 -->-- ~C -->-- T -->-- S1
        //              |                |
        //              +-->-------------+
        //              bbj_cond(true)
        //
        gtReverseCond(condExpr);
        condBlock->bbJumpDest = remainderBlock;
        fgAddRefPred(remainderBlock, condBlock);
        // Since we have no false expr, use the one we'd already created.
        thenBlock = elseBlock;
        elseBlock = nullptr;

        thenBlock->inheritWeightPercentage(condBlock, 50);
    }
    else if (hasFalseExpr)
    {
        //                false
        //     S0 -->-- C -->-- F -->-- S1
        //              |               |
        //              +-->------------+
        //              bbj_cond(true)
        //
        condBlock->bbJumpDest = remainderBlock;
        fgAddRefPred(remainderBlock, condBlock);

        elseBlock->inheritWeightPercentage(condBlock, 50);
    }

    GenTreePtr jmpTree = gtNewOperNode(GT_JTRUE, TYP_VOID, qmark->gtGetOp1());
    GenTreePtr jmpStmt = fgNewStmtFromTree(jmpTree, stmt->gtStmt.gtStmtILoffsx);
    fgInsertStmtAtEnd(condBlock, jmpStmt);

    // Remove the original qmark statement.
    fgRemoveStmt(block, stmt);

    // Since we have top level qmarks, we either have a dst for it in which case
    // we need to create tmps for true and falseExprs, else just don't bother
    // assigning.
    unsigned lclNum = BAD_VAR_NUM;
    if (dst != nullptr)
    {
        assert(dst->gtOper == GT_LCL_VAR);
        lclNum = dst->gtLclVar.gtLclNum;
    }
    else
    {
        assert(qmark->TypeGet() == TYP_VOID);
    }

    if (hasTrueExpr)
    {
        if (dst != nullptr)
        {
            trueExpr = gtNewTempAssign(lclNum, trueExpr);
        }
        GenTreePtr trueStmt = fgNewStmtFromTree(trueExpr, stmt->gtStmt.gtStmtILoffsx);
        fgInsertStmtAtEnd(thenBlock, trueStmt);
    }

    // Assign the falseExpr into the dst or tmp, insert in elseBlock
    if (hasFalseExpr)
    {
        if (dst != nullptr)
        {
            falseExpr = gtNewTempAssign(lclNum, falseExpr);
        }
        GenTreePtr falseStmt = fgNewStmtFromTree(falseExpr, stmt->gtStmt.gtStmtILoffsx);
        fgInsertStmtAtEnd(elseBlock, falseStmt);
    }

#ifdef DEBUG
    if (verbose)
    {
        printf("\nExpanding top-level qmark in BB%02u (after)\n", block->bbNum);
        fgDispBasicBlocks(block, remainderBlock, true);
    }
#endif // DEBUG
}

/*****************************************************************************
 *
 *  Expand GT_QMARK nodes from the flow graph into basic blocks.
 *
 */

void Compiler::fgExpandQmarkNodes()
{
    if (compQmarkUsed)
    {
        for (BasicBlock* block = fgFirstBB; block; block = block->bbNext)
        {
            for (GenTreePtr stmt = block->bbTreeList; stmt; stmt = stmt->gtNext)
            {
                GenTreePtr expr = stmt->gtStmt.gtStmtExpr;
#ifdef DEBUG
                fgPreExpandQmarkChecks(expr);
#endif
                fgExpandQmarkStmt(block, stmt);
            }
        }
#ifdef DEBUG
        fgPostExpandQmarkChecks();
#endif
    }
    compQmarkRationalized = true;
}

#ifdef DEBUG
/*****************************************************************************
 *
 *  Make sure we don't have any more GT_QMARK nodes.
 *
 */
void Compiler::fgPostExpandQmarkChecks()
{
    for (BasicBlock* block = fgFirstBB; block; block = block->bbNext)
    {
        for (GenTreePtr stmt = block->bbTreeList; stmt; stmt = stmt->gtNext)
        {
            GenTreePtr expr = stmt->gtStmt.gtStmtExpr;
            fgWalkTreePre(&expr, Compiler::fgAssertNoQmark, NULL);
        }
    }
}
#endif

/*****************************************************************************
 *
 *  Transform all basic blocks for codegen.
 */

void                Compiler::fgMorph()
{
    noway_assert(!compIsForInlining()); // Inlinee's compiler should never reach here.

    fgOutgoingArgTemps = nullptr;

#ifdef DEBUG
    if  (verbose)
        printf("*************** In fgMorph()\n");
    if  (verboseTrees)
        fgDispBasicBlocks(true);
#endif // DEBUG

    // Insert call to class constructor as the first basic block if
    // we were asked to do so.
    if (info.compCompHnd->initClass(NULL /* field */, info.compMethodHnd /* method */,
            impTokenLookupContextHandle /* context */) & CORINFO_INITCLASS_USE_HELPER)
    {
        fgEnsureFirstBBisScratch();
        fgInsertStmtAtBeg(fgFirstBB, fgInitThisClass());
    }

#ifdef DEBUG
    if (opts.compGcChecks)
    {
        for (unsigned i = 0; i < info.compArgsCount; i++)
        {
            if (lvaTable[i].TypeGet() == TYP_REF)
            {
                // confirm that the argument is a GC pointer (for debugging (GC stress))
                GenTreePtr op = gtNewLclvNode(i, TYP_REF);
                GenTreeArgList* args = gtNewArgList(op);
                op = gtNewHelperCallNode(CORINFO_HELP_CHECK_OBJ, TYP_VOID, 0, args);

                fgEnsureFirstBBisScratch();
                fgInsertStmtAtEnd(fgFirstBB, op);
            }
        }
    }

    if (opts.compStackCheckOnRet)
    {
        lvaReturnEspCheck = lvaGrabTempWithImplicitUse(false DEBUGARG("ReturnEspCheck"));
        lvaTable[lvaReturnEspCheck].lvType = TYP_INT;
    }

    if (opts.compStackCheckOnCall)
    {
        lvaCallEspCheck = lvaGrabTempWithImplicitUse(false DEBUGARG("CallEspCheck"));
        lvaTable[lvaCallEspCheck].lvType = TYP_INT;
    }
#endif // DEBUG

    /* Filter out unimported BBs */

    fgRemoveEmptyBlocks();

    /* Add any internal blocks/trees we may need */

    fgAddInternal();

#if OPT_BOOL_OPS
    fgMultipleNots = false;
#endif

#ifdef DEBUG
    /* Inliner could add basic blocks. Check that the flowgraph data is up-to-date */
    fgDebugCheckBBlist(false, false);
#endif // DEBUG

    /* Inline */
    fgInline();
#if 0
    JITDUMP("trees after inlining\n");
    DBEXEC(VERBOSE, fgDispBasicBlocks(true));
#endif

    RecordStateAtEndOfInlining();  // Record "start" values for post-inlining cycles and elapsed time.

#ifdef DEBUG
    /* Inliner could add basic blocks. Check that the flowgraph data is up-to-date */
    fgDebugCheckBBlist(false, false);
#endif // DEBUG

    /* For x64 and ARM64 we need to mark irregular parameters early so that they don't get promoted */
    fgMarkImplicitByRefArgs();

    /* Promote struct locals if necessary */
    fgPromoteStructs();

    /* Now it is the time to figure out what locals have address-taken. */
    fgMarkAddressExposedLocals();

#ifdef DEBUG
    /* Now that locals have address-taken marked, we can safely apply stress. */
    lvaStressLclFld();
    fgStress64RsltMul();
#endif // DEBUG

    /* Morph the trees in all the blocks of the method */

    fgMorphBlocks();

#if 0
    JITDUMP("trees after fgMorphBlocks\n");
    DBEXEC(VERBOSE, fgDispBasicBlocks(true));
#endif

    /* Decide the kind of code we want to generate */

    fgSetOptions();

    fgExpandQmarkNodes();

#ifdef DEBUG
    compCurBB = 0;
#endif // DEBUG
}


/*****************************************************************************
 *
 *  Promoting struct locals
 */
void                Compiler::fgPromoteStructs()
{
#ifdef DEBUG
    if  (verbose)
        printf("*************** In fgPromoteStructs()\n");
#endif // DEBUG

    if (!opts.OptEnabled(CLFLG_STRUCTPROMOTE))
        return;

    if (fgNoStructPromotion)
        return;

#if 0
    // The code in this #if has been useful in debugging struct promotion issues, by
    // enabling selective enablement of the struct promotion optimization according to
    // method hash.
#ifdef DEBUG
    unsigned methHash = info.compMethodHash();
    char* lostr = getenv("structpromohashlo");
    unsigned methHashLo = 0;
    if (lostr != NULL)
    {
        sscanf_s(lostr, "%x", &methHashLo);
    }
    char* histr = getenv("structpromohashhi");
    unsigned methHashHi = UINT32_MAX;
    if (histr != NULL)
    {
        sscanf_s(histr, "%x", &methHashHi);
    }
    if (methHash < methHashLo || methHash > methHashHi)
    {
        return;
    }
    else
    {
        printf("Promoting structs for method %s, hash = 0x%x.\n",
               info.compFullName, info.compMethodHash());
        printf("");         // in our logic this causes a flush
    }
#endif // DEBUG
#endif // 0

    if (info.compIsVarArgs)
        return;

    if (getNeedsGSSecurityCookie())
        return;

    // The lvaTable might grow as we grab temps. Make a local copy here.

    unsigned        startLvaCount = lvaCount;

    //
    // Loop through the original lvaTable. Looking for struct locals to be promoted.
    //

    lvaStructPromotionInfo structPromotionInfo;
    bool tooManyLocals = false;

    for (unsigned lclNum = 0;
         lclNum < startLvaCount;
         lclNum++)
    {
        // Whether this var got promoted
        bool promotedVar = false;
        LclVarDsc*  varDsc = &lvaTable[lclNum];

#ifdef FEATURE_SIMD
        if (varDsc->lvSIMDType && varDsc->lvUsedInSIMDIntrinsic)
        {
            // If we have marked this as lvUsedInSIMDIntrinsic, then we do not want to promote
            // its fields.  Instead, we will attempt to enregister the entire struct.
            varDsc->lvRegStruct = true;
        }
        else
#endif //FEATURE_SIMD
        // Don't promote if we have reached the tracking limit.
        if (lvaHaveManyLocals())
        {
            // Print the message first time when we detected this condition
            if (!tooManyLocals)
            {
                JITDUMP("Stopped promoting struct fields, due to too many locals.\n");
            }
            tooManyLocals = true;
        }
#if !FEATURE_MULTIREG_STRUCT_PROMOTE
        else if (varDsc->lvIsMultiRegArgOrRet)
        {
            JITDUMP("Skipping V%02u: marked lvIsMultiRegArgOrRet.\n", lclNum);
        }
#endif // !FEATURE_MULTIREG_STRUCT_PROMOTE
        else if (varTypeIsStruct(varDsc))
        {
            lvaCanPromoteStructVar(lclNum, &structPromotionInfo);
            bool canPromote = structPromotionInfo.canPromote;            

            // We start off with shouldPromote same as canPromote.
            // Based on further profitablity checks done below, shouldPromote
            // could be set to false.
            bool shouldPromote = canPromote;

            if (canPromote)
            {
                
                // We *can* promote; *should* we promote?
                // We should only do so if promotion has potential savings.  One source of savings
                // is if a field of the struct is accessed, since this access will be turned into
                // an access of the corresponding promoted field variable.  Even if there are no
                // field accesses, but only block-level operations on the whole struct, if the struct
                // has only one or two fields, then doing those block operations field-wise is probably faster
                // than doing a whole-variable block operation (e.g., a hardware "copy loop" on x86).
                // So if no fields are accessed independently, and there are three or more fields, 
                // then do not promote.
                if (structPromotionInfo.fieldCnt > 2 && !varDsc->lvFieldAccessed)
                {
                    JITDUMP("Not promoting promotable struct local V%02u: #fields = %d, fieldAccessed = %d.\n",
                        lclNum, structPromotionInfo.fieldCnt, varDsc->lvFieldAccessed);
                    shouldPromote = false;
                }
#if defined(_TARGET_AMD64_) || defined(_TARGET_ARM64_)
                // TODO-PERF - Only do this when the LclVar is used in an argument context
                // TODO-ARM64 - HFA support should also eliminate the need for this.
                // TODO-LSRA - Currently doesn't support the passing of floating point LCL_VARS in the integer registers
                //
                // For now we currently don't promote structs with a single float field
                // Promoting it can cause us to shuffle it back and forth between the int and 
                //  the float regs when it is used as a argument, which is very expensive for XARCH
                //
                else if ((structPromotionInfo.fieldCnt == 1) &&
                          varTypeIsFloating(structPromotionInfo.fields[0].fldType))
                {
                    JITDUMP("Not promoting promotable struct local V%02u: #fields = %d because it is a struct with single float field.\n",
                            lclNum, structPromotionInfo.fieldCnt);
                    shouldPromote = false;
                }
#endif // _TARGET_AMD64_ || _TARGET_ARM64_

#if !FEATURE_MULTIREG_STRUCT_PROMOTE
#if defined(_TARGET_ARM64_)
                //
                // For now we currently don't promote structs that could be passed in registers
                //
                else if (varDsc->lvIsMultiregStruct())
                {
                    JITDUMP("Not promoting promotable struct local V%02u (size==%d): ",
                            lclNum, lvaLclExactSize(lclNum));
                    shouldPromote = false;
                }
#endif // _TARGET_ARM64_
#endif // !FEATURE_MULTIREG_STRUCT_PROMOTE
                else if (varDsc->lvIsParam)
                {
#if FEATURE_MULTIREG_STRUCT_PROMOTE                   
                    if (varDsc->lvIsMultiregStruct() &&         // Is this a variable holding a value that is passed in multiple registers?
                        (structPromotionInfo.fieldCnt != 2))    // Does it have exactly two fields
                    {
                        JITDUMP("Not promoting multireg struct local V%02u, because lvIsParam is true and #fields != 2\n",
                                lclNum);
                        shouldPromote = false;
                    }
                    else
#endif  // !FEATURE_MULTIREG_STRUCT_PROMOTE

                    // TODO-PERF - Implement struct promotion for incoming multireg structs
                    //             Currently it hits assert(lvFieldCnt==1) in lclvar.cpp line 4417  

                    if (structPromotionInfo.fieldCnt != 1)
                    {
                        JITDUMP("Not promoting promotable struct local V%02u, because lvIsParam is true and #fields = %d.\n",
                                lclNum, structPromotionInfo.fieldCnt);
                        shouldPromote = false;
                    }
                }

                // 
                // If the lvRefCnt is zero and we have a struct promoted parameter we can end up with an extra store of the the 
                // incoming register into the stack frame slot.
                // In that case, we would like to avoid promortion.
                // However we haven't yet computed the lvRefCnt values so we can't do that.
                // 

#if 0
                // Often-useful debugging code: if you've narrowed down a struct-promotion problem to a single
                // method, this allows you to select a subset of the vars to promote (by 1-based ordinal number).
                static int structPromoVarNum = 0;
                structPromoVarNum++;
                if (atoi(getenv("structpromovarnumlo")) <= structPromoVarNum && structPromoVarNum <= atoi(getenv("structpromovarnumhi")))
#endif // 0

                if (shouldPromote)
                {
                    assert(canPromote);

                    // Promote the this struct local var.
                    lvaPromoteStructVar(lclNum, &structPromotionInfo);
                    promotedVar = true;

#ifdef _TARGET_ARM_
                    if (structPromotionInfo.requiresScratchVar)
                    {
                        // Ensure that the scratch variable is allocated, in case we
                        // pass a promoted struct as an argument.
                        if (lvaPromotedStructAssemblyScratchVar == BAD_VAR_NUM)
                        {
                            lvaPromotedStructAssemblyScratchVar =
                                lvaGrabTempWithImplicitUse(false DEBUGARG("promoted struct assembly scratch var."));
                            lvaTable[lvaPromotedStructAssemblyScratchVar].lvType = TYP_I_IMPL;
                        }
                    }
#endif // _TARGET_ARM_
                }
            }
        }

#ifdef FEATURE_SIMD
        if (!promotedVar && varDsc->lvSIMDType && !varDsc->lvFieldAccessed)
        {
            // Even if we have not used this in a SIMD intrinsic, if it is not being promoted,
            // we will treat it as a reg struct.
            varDsc->lvRegStruct = true;
        }
#endif // FEATURE_SIMD

    }
}


Compiler::fgWalkResult      Compiler::fgMorphStructField(GenTreePtr tree, fgWalkData* fgWalkPre)
{
    noway_assert(tree->OperGet() == GT_FIELD);
    noway_assert(tree->gtFlags & GTF_GLOB_REF);

    GenTreePtr objRef    = tree->gtField.gtFldObj;

    /* Is this an instance data member? */

    if  (objRef)
    {
        if (objRef->gtOper == GT_ADDR)
        {
            GenTreePtr obj =  objRef->gtOp.gtOp1;

            if (obj->gtOper == GT_LCL_VAR)
            {
                unsigned    lclNum = obj->gtLclVarCommon.gtLclNum;
                LclVarDsc*  varDsc = &lvaTable[lclNum];

                if (varTypeIsStruct(obj))
                {
                    if (varDsc->lvPromoted)
                    {
                        // Promoted struct
                        unsigned fldOffset     = tree->gtField.gtFldOffset;
                        unsigned fieldLclIndex = lvaGetFieldLocal(varDsc, fldOffset);
                        noway_assert(fieldLclIndex != BAD_VAR_NUM);

                        tree->SetOper(GT_LCL_VAR);
                        tree->gtLclVarCommon.SetLclNum(fieldLclIndex);
                        tree->gtType   = lvaTable[fieldLclIndex].TypeGet();
                        tree->gtFlags &= GTF_NODE_MASK;
                        tree->gtFlags &= ~GTF_GLOB_REF;

                        GenTreePtr parent = fgWalkPre->parentStack->Index(1);
                        if ((parent->gtOper == GT_ASG) &&  (parent->gtOp.gtOp1 == tree))
                        {
                            tree->gtFlags |= GTF_VAR_DEF;
                            tree->gtFlags |= GTF_DONT_CSE;
                        }
#ifdef DEBUG
                        if (verbose)
                        {
                            printf("Replacing the field in promoted struct with a local var:\n");
                            fgWalkPre->printModified = true;
                        }
#endif // DEBUG
                        return WALK_SKIP_SUBTREES;
                    }
                }
                else
                {
                    // Normed struct
                    // A "normed struct" is a struct that the VM tells us is a basic type. This can only happen if
                    // the struct contains a single element, and that element is 4 bytes (on x64 it can also be 8 bytes).
                    // Normally, the type of the local var and the type of GT_FIELD are equivalent. However, there
                    // is one extremely rare case where that won't be true. An enum type is a special value type
                    // that contains exactly one element of a primitive integer type (that, for CLS programs is named "value__").
                    // The VM tells us that a local var of that enum type is the primitive type of the enum's single field.
                    // It turns out that it is legal for IL to access this field using ldflda or ldfld. For example:
                    //
                    //  .class public auto ansi sealed mynamespace.e_t extends [mscorlib]System.Enum
                    //  {
                    //    .field public specialname rtspecialname int16 value__
                    //    .field public static literal valuetype mynamespace.e_t one = int16(0x0000)
                    //  }
                    //  .method public hidebysig static void  Main() cil managed
                    //  {
                    //     .locals init (valuetype mynamespace.e_t V_0)
                    //     ...
                    //     ldloca.s   V_0
                    //     ldflda     int16 mynamespace.e_t::value__
                    //     ...
                    //  }
                    //
                    // Normally, compilers will not generate the ldflda, since it is superfluous.
                    //
                    // In the example, the lclVar is short, but the JIT promotes all trees using this local to the
                    // "actual type", that is, INT. But the GT_FIELD is still SHORT. So, in the case of a type
                    // mismatch like this, don't do this morphing. The local var may end up getting marked as
                    // address taken, and the appropriate SHORT load will be done from memory in that case.

                    if (tree->TypeGet() == obj->TypeGet())
                    {
                        tree->ChangeOper(GT_LCL_VAR);
                        tree->gtLclVarCommon.SetLclNum(lclNum);
                        tree->gtFlags &= GTF_NODE_MASK;

                        GenTreePtr parent = fgWalkPre->parentStack->Index(1);
                        if ((parent->gtOper == GT_ASG) && (parent->gtOp.gtOp1 == tree))
                        {
                            tree->gtFlags |= GTF_VAR_DEF;
                            tree->gtFlags |= GTF_DONT_CSE;
                        }
#ifdef DEBUG
                        if (verbose)
                        {
                            printf("Replacing the field in normed struct with the local var:\n");
                            fgWalkPre->printModified = true;
                        }
#endif // DEBUG
                        return WALK_SKIP_SUBTREES;
                    }
                }
            }
        }
    }

    return WALK_CONTINUE;
}

Compiler::fgWalkResult      Compiler::fgMorphLocalField(GenTreePtr tree, fgWalkData* fgWalkPre)
{
    noway_assert(tree->OperGet() == GT_LCL_FLD);

    unsigned    lclNum = tree->gtLclFld.gtLclNum;
    LclVarDsc*  varDsc = &lvaTable[lclNum];

    if (varTypeIsStruct(varDsc) && (varDsc->lvPromoted))
    {
        // Promoted struct
        unsigned    fldOffset = tree->gtLclFld.gtLclOffs;
        unsigned    fieldLclIndex = 0;
        LclVarDsc*  fldVarDsc = NULL;

        if (fldOffset != BAD_VAR_NUM)
        {
            fieldLclIndex = lvaGetFieldLocal(varDsc, fldOffset);
            noway_assert(fieldLclIndex != BAD_VAR_NUM);
            fldVarDsc = &lvaTable[fieldLclIndex];
        }

        if (fldOffset != BAD_VAR_NUM && genTypeSize(fldVarDsc->TypeGet()) == genTypeSize(tree->gtType)
#ifdef _TARGET_X86_
            && varTypeIsFloating(fldVarDsc->TypeGet()) == varTypeIsFloating(tree->gtType)
#endif
            )
        {
            // There is an existing sub-field we can use
            tree->gtLclFld.SetLclNum(fieldLclIndex);

            // We need to keep the types 'compatible'.  If we can switch back to a GT_LCL_VAR
            assert(varTypeIsIntegralOrI(tree->TypeGet()));
            if (varTypeCanReg(fldVarDsc->TypeGet()))
            {
                // If the type is integer-ish, then we can use it as-is
                tree->ChangeOper(GT_LCL_VAR);
                assert(tree->gtLclVarCommon.gtLclNum == fieldLclIndex);
                tree->gtType = fldVarDsc->TypeGet();
#ifdef DEBUG
                if (verbose)
                {
                    printf("Replacing the GT_LCL_FLD in promoted struct with a local var:\n");
                    fgWalkPre->printModified = true;
                }
#endif // DEBUG
            }

            GenTreePtr parent = fgWalkPre->parentStack->Index(1);
            if ((parent->gtOper == GT_ASG) &&  (parent->gtOp.gtOp1 == tree))
            {
                tree->gtFlags |= GTF_VAR_DEF;
                tree->gtFlags |= GTF_DONT_CSE;
            }
        }
        else
        {
            // There is no existing field that has all the parts that we need
            // So we must ensure that the struct lives in memory.
            lvaSetVarDoNotEnregister(lclNum DEBUGARG(DNER_LocalField));

#ifdef DEBUG
            // We can't convert this guy to a float because he really does have his
            // address taken..
            varDsc->lvKeepType = 1;
#endif // DEBUG
        }

        return WALK_SKIP_SUBTREES;
    }

    return WALK_CONTINUE;
}

/*****************************************************************************
 *
 *  Mark irregular parameters.  For x64 this is 3, 5, 6, 7, >8 byte structs that are passed by reference.
 *  For ARM64, this is structs larger than 16 bytes that are passed by reference.
 */
void                Compiler::fgMarkImplicitByRefArgs()
{
#if defined(_TARGET_AMD64_) || defined(_TARGET_ARM64_)
#ifdef DEBUG
    if  (verbose)
        printf("\n*************** In fgMarkImplicitByRefs()\n");
#endif // DEBUG

    for (unsigned lclNum = 0; lclNum < lvaCount; lclNum++)
    {
        LclVarDsc* varDsc = &lvaTable[lclNum];

        assert(!varDsc->lvPromoted);     // Called in the wrong order?

        if (varDsc->lvIsParam && varTypeIsStruct(varDsc))
        {
            size_t size;

            if (varDsc->lvSize() > REGSIZE_BYTES)
            {
                size = varDsc->lvSize();
            }
            else
            {
                CORINFO_CLASS_HANDLE typeHnd = varDsc->lvVerTypeInfo.GetClassHandle();
                size = info.compCompHnd->getClassSize(typeHnd);
            }


#if !defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
#if defined(_TARGET_AMD64_)
            if (size > REGSIZE_BYTES || (size & (size - 1)) != 0)
#elif defined(_TARGET_ARM64_)
            if (size > 16)
#endif
            {
                // Previously nobody was ever setting lvIsParam and lvIsTemp on the same local
                // So I am now using it to indicate that this is one of the weird implicit
                // by ref locals.
                // The address taken cleanup will look for references to locals marked like
                // this, and transform them appropriately.
                varDsc->lvIsTemp = 1;

                // Also marking them as BYREF will hide them from struct promotion.
                varDsc->lvType = TYP_BYREF;

                varDsc->lvRefCnt = 0;

                // Since this previously was a TYP_STRUCT and we have changed it to a TYP_BYREF
                // make sure that the following flag is not set as these will force SSA to
                // exclude tracking/enregistering these LclVars. (see fgExcludeFromSsa)
                //                
                varDsc->lvOverlappingFields = 0;    // This flag could have been set, clear it.

#ifdef DEBUG
                // This should not be converted to a double in stress mode,
                // because it is really a pointer
                varDsc->lvKeepType = 1;
#endif // DEBUG
            }
#endif // !FEATURE_UNIX_AMD64_STRUCT_PASSING
        }
    }

#endif // _TARGET_AMD64_ || _TARGET_ARM64_
}

/*****************************************************************************
 *
 *  Morph irregular parameters
 *    for x64 and ARM64 this means turning them into byrefs, adding extra indirs.
 */
bool Compiler::fgMorphImplicitByRefArgs(GenTreePtr tree, fgWalkData* fgWalkPre)
{
#if !defined(_TARGET_AMD64_) && !defined(_TARGET_ARM64_)

    return false;

#else // _TARGET_AMD64_ || _TARGET_ARM64_

    assert((tree->gtOper == GT_LCL_VAR) ||
           ((tree->gtOper == GT_ADDR) && (tree->gtOp.gtOp1->gtOper == GT_LCL_VAR)));

    bool        isAddr     = (tree->gtOper == GT_ADDR);
    GenTreePtr  lclVarTree = isAddr ? tree->gtOp.gtOp1 : tree;
    unsigned    lclNum     = lclVarTree->gtLclVarCommon.gtLclNum;
    LclVarDsc*  lclVarDsc  = &lvaTable[lclNum];

    if (!lvaIsImplicitByRefLocal(lclNum))
    {
        // We only need to tranform the 'marked' implicit by ref parameters
        return false;
    }

    // The SIMD transformation to coalesce contiguous references to SIMD vector fields will
    // re-invoke the traversal to mark address-taken locals.
    // So, we may encounter a tree that has already been transformed to TYP_BYREF.
    // If we do, leave it as-is.
    if (!varTypeIsStruct(lclVarTree))
    {
        assert(lclVarTree->TypeGet() == TYP_BYREF);
        return false;
    }

    // We are overloading the lvRefCnt field here because real ref counts have not been set.
    lclVarDsc->lvRefCnt++;

    if (isAddr)
    {
        // change &X into just plain X
        tree->CopyFrom(lclVarTree, this);
        tree->gtType = TYP_BYREF;

#ifdef DEBUG
        if (verbose)
        {
            printf("Replacing address of implicit by ref struct parameter with byref:\n");
            fgWalkPre->printModified = true;
        }
#endif // DEBUG
    }
    else
    {
        // Change X into *X
        // First, save the original type, then change the tree type to TYP_BYREF (otherwise we
        // will get an assert when we try to clone the lclVar node because the lclVar is now TYP_BYREF
        // and the types have to match). The reason we clone the lclVar is that we don't pass a
        // possible-modified tree back to the caller, so we modify the original lclVar node in-place
        // to the GT_IND.
        var_types structType = tree->gtType;
        lclVarTree = gtClone(tree);
        // Now, set the types appropriately.
        lclVarTree->gtType = TYP_BYREF;
        tree->gtType = structType;
        // Now, "insert" the GT_IND by changing the oper of the original node and setting its op1.
        tree->SetOper(GT_IND);
        tree->gtOp.gtOp1 = lclVarTree;
        // TODO-CQ: If the VM ever stops violating the ABI and passing heap references
        // we could remove TGTANYWHERE
        tree->gtFlags = ((tree->gtFlags & GTF_COMMON_MASK) | GTF_IND_TGTANYWHERE);

#ifdef DEBUG
        if (verbose)
        {
            printf("Replacing value of implicit by ref struct parameter with indir of parameter:\n");
            gtDispTree(tree, nullptr, nullptr, true);
            fgWalkPre->printModified = true;
        }
#endif // DEBUG
    }

    return true;

#endif // _TARGET_AMD64_ || _TARGET_ARM64_

}


// An "AddrExposedContext" expresses the calling context in which an address expression occurs.
enum AddrExposedContext
{
    AXC_None,     // None of the below seen yet.
    AXC_Ind,      // The address being computed is to be dereferenced.
    AXC_Addr,     // We're computing a raw address (not dereferenced, at least not immediately).
    AXC_IndWide,  // A block operation dereferenced an address referencing more bytes than the address
                  // addresses -- if the address addresses a field of a struct local, we need to consider
                  // the entire local address taken (not just the field).
    AXC_AddrWide, // The address being computed will be dereferenced by a block operation that operates
                  // on more bytes than the width of the storage location addressed.  If this is a
                  // field of a promoted struct local, declare the entire struct local address-taken.
    AXC_InitBlk,  // An GT_INITBLK is the immediate parent.  The first argument is in an IND context.
    AXC_CopyBlk,  // An GT_COPYBLK is the immediate parent.  The first argument is in a GT_LIST, whose
                  // args should be evaluated in an IND context.
    AXC_IndAdd,   // A GT_ADD is the immediate parent, and it was evaluated in an IND contxt.
                  // If one arg is a constant int, evaluate the other in an IND context.  Otherwise, none.
};

typedef ArrayStack<AddrExposedContext> AXCStack;

// We use pre-post to simulate passing an argument in a recursion, via a stack.
Compiler::fgWalkResult      Compiler::fgMarkAddrTakenLocalsPostCB(GenTreePtr* pTree,
                                                                  fgWalkData* fgWalkPre)
{
    AXCStack* axcStack = reinterpret_cast<AXCStack*>(fgWalkPre->pCallbackData);
    (void)axcStack->Pop();
    return WALK_CONTINUE;
}

Compiler::fgWalkResult      Compiler::fgMarkAddrTakenLocalsPreCB(GenTreePtr* pTree,
                                                                 fgWalkData* fgWalkPre)
{
    GenTreePtr tree = *pTree;
    Compiler*  comp = fgWalkPre->compiler;
    AXCStack*  axcStack = reinterpret_cast<AXCStack*>(fgWalkPre->pCallbackData);
    AddrExposedContext axc = axcStack->Top();

    // In some situations, we have to figure out what the effective context is in which to
    // evaluate the current tree, depending on which argument position it is in its parent.

    // If the parent was an initblock, and this is its first argument, we're in
    // and "ind" context.
    switch (axc)
    {
    case AXC_InitBlk:
    case AXC_CopyBlk:
        {
            // In both cases, the second argument is an integer struct size.  That should have a "none" context.
            // The first argument is a GT_LIST.  For GT_COPYBLK, both args of the list are addresses
            // that are dereferenced; for GT_INITBLK, the first is.  We pass "axc" to the GT_LIST;
            // which will pass it to its arguments; these will decide whether they're in an Ind context
            // depending on "axc" and which argument they are.
            // A GT_INITBLK's first argument is a GT_LIST, whose first argument is an address
            // that should be considered to be dereferenced, and whose second argument the integer
            // (byte) value to fill the block with.  The second argument of the GT_INITBLK is also
            // an integer, the block size.
            GenTreePtr parent = fgWalkPre->parentStack->Index(1);
            if (parent->gtOp.gtOp2 == tree &&
                parent->OperIsBlkOp())
            {
                axc = AXC_None;
            }
            else if (parent->OperGet() == GT_LIST)
            {
                genTreeOps axcOper = fgWalkPre->parentStack->Index(2)->OperGet();
                assert((axc == AXC_InitBlk && axcOper == GT_INITBLK) ||
                       (axc == AXC_CopyBlk && GenTree::OperIsCopyBlkOp(axcOper)));

                // The block operation will derefence its argument(s) -- usually.  If the size of the initblk
                // or copyblk exceeds the size of a storage location whose address is used as one of the
                // arguments, then we have to consider that storage location (indeed, it's underlying containing
                // location) to be address taken.  So get the width of the initblk or copyblk.
                GenTreePtr widthNode = fgWalkPre->parentStack->Index(2)->gtOp.gtOp2;
                unsigned width = UINT_MAX;  // If it's not a constant, assume it's maximally big.
                if (widthNode->IsCnsIntOrI())
                {
                    if (widthNode->IsIconHandle())
                    {
                        // If it's a handle, it must be a class handle.  We only create such block operations
                        // for initialization of struct types, so the type of the argument(s) will match this
                        // type, by construction.  Set the width to zero to make sure nothing fits in it.
                        assert(widthNode->IsIconHandle(GTF_ICON_CLASS_HDL));
                        width = 0;
                    }
                    else
                    {
                        ssize_t swidth = widthNode->gtIntConCommon.IconValue();
                        assert(swidth > 0); // Well-formedness of the block operation node...
                        width = unsigned(swidth);
                    }
                }

                if (parent->gtOp.gtOp1 == tree)
                {
                    // First argument is (potentially) dereferenced by both kinds of block operations.
                    if (tree->OperGet() == GT_ADDR && !comp->fgFitsInOrNotLoc(tree->gtOp.gtOp1, width))
                    {
                        axc = AXC_IndWide;
                    }
                    else
                    {
                        axc = AXC_Ind;
                    }
                }
                else if (axc == AXC_CopyBlk)
                {
                    assert(parent->gtOp.gtOp2 == tree);
                    if (tree->OperGet() == GT_ADDR && !comp->fgFitsInOrNotLoc(tree->gtOp.gtOp1, width))
                    {
                        axc = AXC_IndWide;
                    }
                    else
                    {
                        axc = AXC_Ind;
                    }
                }
                else
                {
                    axc = AXC_None;
                }
            }
        }
        break;

    case AXC_IndAdd:
        {
            GenTreePtr parent = fgWalkPre->parentStack->Index(1);
            assert(parent->OperGet() == GT_ADD);
            // Is one of the args a constant representing a field offset,
            // and is this the other?  If so, Ind context.
            if (parent->gtOp.gtOp1->IsCnsIntOrI() && parent->gtOp.gtOp2 == tree)
            {
                axc = AXC_Ind;
            }
            else if (parent->gtOp.gtOp2->IsCnsIntOrI() && parent->gtOp.gtOp1 == tree)
            {
                axc = AXC_Ind;
            }
            else
            {
                axc = AXC_None;
            }
        }
        break;

    default:
        break;
    }

    // Now recurse properly for the tree.
    switch (tree->gtOper)
    {
    case GT_IND:
    case GT_OBJ:
        if (axc != AXC_Addr)
        {
            axcStack->Push(AXC_Ind);
        }
        else
        {
            axcStack->Push(AXC_None);
        }
        return WALK_CONTINUE;

    case GT_INITBLK:
        axcStack->Push(AXC_InitBlk);
        return WALK_CONTINUE;

    case GT_COPYOBJ:
    case GT_COPYBLK:
        axcStack->Push(AXC_CopyBlk);
        return WALK_CONTINUE;

    case GT_LIST:
        if (axc == AXC_InitBlk || axc == AXC_CopyBlk)
        {
            axcStack->Push(axc);
        }
        else
        {
            axcStack->Push(AXC_None);
        }
        return WALK_CONTINUE;

    case GT_INDEX:
        // Taking the address of an array element never takes the address of a local.
        axcStack->Push(AXC_None);
        return WALK_CONTINUE;

    case GT_ADDR:
        // If we have ADDR(lcl), and "lcl" is an implicit byref parameter, fgMorphImplicitByRefArgs will
        // convert to just "lcl".  This is never an address-context use, since the local is already a
        // byref after this transformation.
        if (tree->gtOp.gtOp1->OperGet() == GT_LCL_VAR && comp->fgMorphImplicitByRefArgs(tree, fgWalkPre))
        {
            // Push something to keep the PostCB, which will pop it, happy.
            axcStack->Push(AXC_None);
            // In the first case, tree may no longer be a leaf, but we're done with it; is a leaf in the second case.
            return WALK_SKIP_SUBTREES;
        }
        // Otherwise...
#ifdef FEATURE_SIMD
        if (tree->gtOp.gtOp1->OperGet() == GT_SIMD)
        {
            axcStack->Push(AXC_None);
        }
        else
#endif // FEATURE_SIMD
        if (axc == AXC_Ind)
        {
            axcStack->Push(AXC_None);
        }
        else if (axc == AXC_IndWide)
        {
            axcStack->Push(AXC_AddrWide);
        }
        else
        {
            assert(axc == AXC_None);
            axcStack->Push(AXC_Addr);
        }
        return WALK_CONTINUE;

    case GT_FIELD:
        // First, handle a couple of special cases: field of promoted struct local, field
        // of "normed" struct.
        if (comp->fgMorphStructField(tree, fgWalkPre) == WALK_SKIP_SUBTREES)
        {
            // It (may have) replaced the field with a local var or local field.  If we're in an addr context,
            // label it addr-taken.
            if (tree->OperIsLocal() && (axc == AXC_Addr || axc == AXC_AddrWide))
            {
                unsigned lclNum = tree->gtLclVarCommon.gtLclNum;
                comp->lvaSetVarAddrExposed(lclNum);
                if (axc == AXC_AddrWide)
                {
                    LclVarDsc* varDsc = &comp->lvaTable[lclNum];
                    if (varDsc->lvIsStructField)
                    {
                        comp->lvaSetVarAddrExposed(varDsc->lvParentLcl);
                    }
                }
            }
            // Push something to keep the PostCB, which will pop it, happy.
            axcStack->Push(AXC_None);
            return WALK_SKIP_SUBTREES;
        }
        else
        {
            // GT_FIELD is an implicit deref.
            if (axc == AXC_Addr)
            {
                axcStack->Push(AXC_None);
            }
            else if (axc == AXC_AddrWide)
            {
                axcStack->Push(AXC_IndWide);
            }
            else
            {
                axcStack->Push(AXC_Ind);
            }
            return WALK_CONTINUE;
        }

    case GT_LCL_FLD:
        {
            assert(axc != AXC_Addr);
            // This recognizes certain forms, and does all the work.  In that case, returns WALK_SKIP_SUBTREES,
            // else WALK_CONTINUE.  We do the same here.
            fgWalkResult res = comp->fgMorphLocalField(tree, fgWalkPre);
            if (res == WALK_SKIP_SUBTREES && tree->OperGet() == GT_LCL_VAR && (axc == AXC_Addr || axc == AXC_AddrWide))
            {
                unsigned lclNum = tree->gtLclVarCommon.gtLclNum;
                comp->lvaSetVarAddrExposed(lclNum);
                if (axc == AXC_AddrWide)
                {
                    LclVarDsc* varDsc = &comp->lvaTable[lclNum];
                    if (varDsc->lvIsStructField)
                    {
                        comp->lvaSetVarAddrExposed(varDsc->lvParentLcl);
                    }
                }
            }
            // Must push something; if res is WALK_SKIP_SUBTREES, doesn't matter
            // what, but something to be popped by the post callback.  If we're going
            // to analyze children, the LCL_FLD creates an Ind context, so use that.
            axcStack->Push(AXC_Ind);
            return res;
        }

    case GT_LCL_VAR:
        // On some architectures, some arguments are passed implicitly by reference.
        // Modify the trees to reflect that, if this local is one of those.
        if (comp->fgMorphImplicitByRefArgs(tree, fgWalkPre))
        {
            // We can't be in an address context; the ADDR(lcl), where lcl is an implicit byref param, was
            // handled earlier.  (And we can't have added anything to this address, since it was implicit.)
            assert(axc != AXC_Addr);
        }
        else
        {
            if (axc == AXC_Addr || axc == AXC_AddrWide)
            {
                unsigned lclNum = tree->gtLclVarCommon.gtLclNum;
                comp->lvaSetVarAddrExposed(lclNum);
                if (axc == AXC_AddrWide)
                {
                    LclVarDsc* varDsc = &comp->lvaTable[lclNum];
                    if (varDsc->lvIsStructField)
                    {
                        comp->lvaSetVarAddrExposed(varDsc->lvParentLcl);
                    }
                }

                // We may need to Quirk the storage size for this LCL_VAR
                // some PInvoke signatures incorrectly specify a ByRef to an INT32
                // when they actually write a SIZE_T or INT64
                if (axc == AXC_Addr)
                {
                    comp->gtCheckQuirkAddrExposedLclVar(tree, fgWalkPre->parentStack); 
                }
            }
        }
        // Push something to keep the PostCB, which will pop it, happy.
        axcStack->Push(AXC_None);
        // In the first case, tree may no longer be a leaf, but we're done with it; is a leaf in the second case.
        return WALK_SKIP_SUBTREES;

    case GT_ADD:
        assert(axc != AXC_Addr);
        // See below about treating pointer operations as wider indirection.
        if (tree->gtOp.gtOp1->gtType == TYP_BYREF || tree->gtOp.gtOp2->gtType == TYP_BYREF)
        {
            axcStack->Push(AXC_IndWide);
        }
        else if (axc == AXC_Ind)
        {
            // Let the children know that the parent was a GT_ADD, to be evaluated in an IND context.
            // If it's an add of a constant and an address, and the constant represents a field,
            // then we'll evaluate the address argument in an Ind context; otherwise, the None context.
            axcStack->Push(AXC_IndAdd);
        }
        else
        {
            axcStack->Push(axc);
        }
        return WALK_CONTINUE;

    // !!! Treat Pointer Operations as Wider Indirection
    //
    // If we are performing pointer operations, make sure we treat that as equivalent to a wider
    // indirection. This is because the pointers could be pointing to the address of struct fields
    // and could be used to perform operations on the whole struct or passed to another method.
    // 
    // When visiting a node in this pre-order walk, we do not know if we would in the future
    // encounter a GT_ADDR of a GT_FIELD below.
    //
    // Note: GT_ADDR of a GT_FIELD is always a TYP_BYREF.
    // So let us be conservative and treat TYP_BYREF operations as AXC_IndWide and propagate a
    // wider indirection context down the expr tree.
    //
    // Example, in unsafe code,
    //
    //   IL_000e  12 00             ldloca.s     0x0
    //   IL_0010  7c 02 00 00 04    ldflda       0x4000002
    //   IL_0015  12 00             ldloca.s     0x0
    //   IL_0017  7c 01 00 00 04    ldflda       0x4000001
    //   IL_001c  59                sub
    //
    // When visiting the GT_SUB node, if the types of either of the GT_SUB's operand are BYREF, then
    // consider GT_SUB to be equivalent of an AXC_IndWide.
    //
    // Similarly for pointer comparisons and pointer escaping as integers through conversions, treat
    // them as AXC_IndWide.
    //
    
    // BINOP
    case GT_SUB:
    case GT_MUL:
    case GT_DIV:
    case GT_UDIV:
    case GT_OR:
    case GT_XOR:
    case GT_AND:
    case GT_LSH:
    case GT_RSH:
    case GT_RSZ:
    case GT_ROL:
    case GT_ROR:
    case GT_EQ:
    case GT_NE:
    case GT_LT:
    case GT_LE:
    case GT_GT:
    case GT_GE:
    // UNOP
    case GT_CAST:
        if ((tree->gtOp.gtOp1->gtType == TYP_BYREF) || (tree->OperIsBinary() && (tree->gtOp.gtOp2->gtType == TYP_BYREF)))
        {
            axcStack->Push(AXC_IndWide);
            return WALK_CONTINUE;
        }
        __fallthrough;

    default:
        // To be safe/conservative: pass Addr through, but not Ind -- otherwise, revert to "None".  We must
        // handle the "Ind" propogation explicitly above.
        if (axc == AXC_Addr || axc == AXC_AddrWide)
        {
            axcStack->Push(axc);
        }
        else
        {
            axcStack->Push(AXC_None);
        }
        return WALK_CONTINUE;
    }
}

bool Compiler::fgFitsInOrNotLoc(GenTreePtr tree, unsigned width)
{
    if (tree->TypeGet() != TYP_STRUCT)
    {
        return width <= genTypeSize(tree->TypeGet());
    }
    else if (tree->OperGet() == GT_LCL_VAR)
    {
        assert(tree->TypeGet() == TYP_STRUCT);
        unsigned lclNum = tree->gtLclVarCommon.gtLclNum;
        return width <= lvaTable[lclNum].lvExactSize;
    }
    else if (tree->OperGet() == GT_FIELD)
    {
        CORINFO_CLASS_HANDLE fldClass = info.compCompHnd->getFieldClass (tree->gtField.gtFldHnd);
        return width <= info.compCompHnd->getClassSize(fldClass);
    }
    else
    {
        return false;
    }
}


void Compiler::fgAddFieldSeqForZeroOffset(GenTreePtr op1, FieldSeqNode* fieldSeq)
{
    assert(op1->TypeGet() == TYP_BYREF || op1->TypeGet() == TYP_I_IMPL || op1->TypeGet() == TYP_REF);

    switch (op1->OperGet())
    {
    case GT_ADDR:
        if (op1->gtOp.gtOp1->OperGet() == GT_LCL_FLD)
        {
            GenTreeLclFld* lclFld = op1->gtOp.gtOp1->AsLclFld();
            lclFld->gtFieldSeq = GetFieldSeqStore()->Append(lclFld->gtFieldSeq, fieldSeq);
        }
        break;

    case GT_ADD:
        if (op1->gtOp.gtOp1->OperGet() == GT_CNS_INT)
        {
            FieldSeqNode* op1Fs = op1->gtOp.gtOp1->gtIntCon.gtFieldSeq;
            if (op1Fs != NULL)
            {
                op1Fs = GetFieldSeqStore()->Append(op1Fs, fieldSeq);
                op1->gtOp.gtOp1->gtIntCon.gtFieldSeq = op1Fs;
            }
        }
        else if (op1->gtOp.gtOp2->OperGet() == GT_CNS_INT)
        {
            FieldSeqNode* op2Fs = op1->gtOp.gtOp2->gtIntCon.gtFieldSeq;
            if (op2Fs != NULL)
            {
                op2Fs = GetFieldSeqStore()->Append(op2Fs, fieldSeq);
                op1->gtOp.gtOp2->gtIntCon.gtFieldSeq = op2Fs;
            }
        }
        break;

    case GT_CNS_INT:
        {
            FieldSeqNode* op1Fs = op1->gtIntCon.gtFieldSeq;
            if (op1Fs != NULL)
            {
                op1Fs = GetFieldSeqStore()->Append(op1Fs, fieldSeq);
                op1->gtIntCon.gtFieldSeq = op1Fs;
            }
        }
        break;

    default:
        // Record in the general zero-offset map.
        GetZeroOffsetFieldMap()->Set(op1, fieldSeq);
        break;
    }
}

/*****************************************************************************
 *
 *  Mark address-taken locals.
 */

void                Compiler::fgMarkAddressExposedLocals()
{
#ifdef DEBUG
    if  (verbose)
        printf("\n*************** In fgMarkAddressExposedLocals()\n");
#endif // DEBUG

    BasicBlock* block = fgFirstBB;
    noway_assert(block);

    do
    {
        /* Make the current basic block address available globally */

        compCurBB = block;

        GenTreePtr stmt;

        for (stmt = block->bbTreeList;
             stmt;
             stmt = stmt->gtNext)
        {
            // Call Compiler::fgMarkAddrTakenLocalsCB on each node
            AXCStack stk(this);
            stk.Push(AXC_None); // We start in neither an addr or ind context.
            fgWalkTree(&stmt->gtStmt.gtStmtExpr,
                       fgMarkAddrTakenLocalsPreCB,
                       fgMarkAddrTakenLocalsPostCB,
                       &stk);
        }

        block = block->bbNext;

    } while (block);
}


// fgNodesMayInterfere:
//   return true if moving nodes relative to each other can change the result of a computation
//
// args:
//   read: a node which reads
//   

bool Compiler::fgNodesMayInterfere(GenTree* write, GenTree* read)
{
    LclVarDsc* srcVar = nullptr;
    bool srcAliased = false;
    bool dstAliased = false;

    bool readIsIndir  = read->OperIsIndir()  || read->OperIsImplicitIndir();
    bool writeIsIndir = write->OperIsIndir() || write->OperIsImplicitIndir();

    if (read->OperIsLocal())
        srcVar = &lvaTable[read->gtLclVarCommon.gtLclNum];
    
    if (writeIsIndir)
    {
        if (srcVar && srcVar->lvAddrExposed)
            return true;
        else if (readIsIndir)
            return true;
        return false;
    }
    else if (write->OperIsLocal())
    {
        LclVarDsc* dstVar = &lvaTable[write->gtLclVarCommon.gtLclNum];
        if (readIsIndir)
        {
            return dstVar->lvAddrExposed;
        }
        else if (read->OperIsLocal())
        {
            if (read->gtLclVarCommon.gtLclNum == write->gtLclVarCommon.gtLclNum)
                return true;
            return false;
        }
        else
        {
            return false;
        }
    }
    else
    {
        return false;
    }
}

/** This predicate decides whether we will fold a tree with the structure:
 *  x = x <op> y where x could be any arbitrary expression into
 *  x <op>= y.
 *
 *  This modification is only performed when the target architecture supports
 *  complex addressing modes.  In the case of ARM for example, this transformation
 *  yields no benefit.
 *
 *  In case this functions decides we can proceed to fold into an assignment operator
 *  we need to inspect whether the operator is commutative to tell fgMorph whether we need to
 *  reverse the tree due to the fact we saw x = y <op> x and we want to fold that into
 *  x <op>= y because the operator property.
 */
bool                Compiler::fgShouldCreateAssignOp(GenTreePtr tree, bool* bReverse)
{
#if CPU_LOAD_STORE_ARCH
    /* In the case of a load/store architecture, there's no gain by doing any of this, we bail. */
    return false;
#elif !defined(LEGACY_BACKEND)
    return false;
#else // defined(LEGACY_BACKEND)


    GenTreePtr op1 = tree->gtOp.gtOp1;
    GenTreePtr op2 = tree->gtGetOp2();
    genTreeOps cmop = op2->OperGet();

    /* Is the destination identical to the first RHS sub-operand? */
    if  (GenTree::Compare(op1, op2->gtOp.gtOp1))
    {
        /*
        Do not transform the following tree

        [0024CFA4] -----------               const     int    1
        [0024CFDC] ----G------               |         int
        [0024CF5C] -----------               lclVar    ubyte  V01 tmp0
        [0024D05C] -A--G------               =         ubyte
        [0024D014] D------N---               lclVar    ubyte  V01 tmp0

        to

        [0024CFA4] -----------               const     int    1
        [0024D05C] -A--G------               |=        ubyte
        [0024D014] U------N---               lclVar    ubyte  V01 tmp0

        , when V01 is a struct field local.
        */

        if (op1->gtOper == GT_LCL_VAR       &&
            varTypeIsSmall(op1->TypeGet())  &&
            op1->TypeGet() != op2->gtOp.gtOp2->TypeGet())
        {
            unsigned     lclNum = op1->gtLclVarCommon.gtLclNum;
            LclVarDsc*   varDsc = lvaTable + lclNum;

            if (varDsc->lvIsStructField)
            {
                return false;
            }
        }

        *bReverse = false;
        return true;
    }
    else if (GenTree::OperIsCommutative(cmop))
    {
        /* For commutative ops only, check for "a = x <op> a" */

        /* Should we be doing this at all? */
        if  ((opts.compFlags & CLFLG_TREETRANS) == 0)
        {
            return false;
        }

        /* Can we swap the operands to cmop ... */
        if ((op2->gtOp.gtOp1->gtFlags & GTF_ALL_EFFECT) &&
            (op2->gtOp.gtOp2->gtFlags & GTF_ALL_EFFECT)    )
        {
            // Both sides must have side effects to prevent swap */
            return false;
        }

        /* Is the destination identical to the second RHS sub-operand? */
        if  (GenTree::Compare(op1, op2->gtOp.gtOp2))
        {
            *bReverse = true;
            return true;
        }
    }
    return false;
#endif // defined(LEGACY_BACKEND)
}

// Static variables.
Compiler::MorphAddrContext Compiler::s_CopyBlockMAC(Compiler::MACK_CopyBlock);

#ifdef FEATURE_SIMD

//-----------------------------------------------------------------------------------
// fgMorphCombineSIMDFieldAssignments:
//  If the RHS of the input stmt is a read for simd vector X Field, then this function
//  will keep reading next few stmts based on the vector size(2, 3, 4). 
//  If the next stmts LHS are located contiguous and RHS are also located 
//  contiguous, then we replace those statements with a copyblk.
//
// Argument:
//  block - BasicBlock*. block which stmt belongs to
//  stmt  - GenTreeStmt*. the stmt node we want to check
//
// return value:
//  if this funciton successfully optimized the stmts, then return true. Otherwise 
//  return false;

bool Compiler::fgMorphCombineSIMDFieldAssignments(BasicBlock* block, GenTreePtr stmt)
{

    noway_assert(stmt->gtOper == GT_STMT);
    GenTreePtr tree = stmt->gtStmt.gtStmtExpr;
    assert(tree->OperGet() == GT_ASG);

    GenTreePtr originalLHS = tree->gtOp.gtOp1;
    GenTreePtr prevLHS = tree->gtOp.gtOp1;
    GenTreePtr prevRHS = tree->gtOp.gtOp2;
    unsigned index = 0;
    var_types baseType = TYP_UNKNOWN;
    unsigned simdSize = 0;
    GenTreePtr simdStructNode = getSIMDStructFromField(prevRHS, &baseType, &index, &simdSize, true);

    if (simdStructNode == nullptr ||
        index != 0                ||
        baseType != TYP_FLOAT)
    {
        // if the RHS is not from a SIMD vector field X, then there is no need to check further.
        return false;
    }

    int assignmentsCount = simdSize / genTypeSize(baseType) - 1;
    int remainingAssignments = assignmentsCount;
    GenTreePtr curStmt = stmt->gtNext;
    GenTreePtr lastStmt = stmt;

    while (curStmt != nullptr && remainingAssignments > 0)
    {
        GenTreePtr exp = curStmt->gtStmt.gtStmtExpr;
        if (exp->OperGet() != GT_ASG)
        {
            break;
        }
        GenTreePtr curLHS = exp->gtGetOp1();
        GenTreePtr curRHS = exp->gtGetOp2();

        if (!areArgumentsContiguous(prevLHS, curLHS) ||
            !areArgumentsContiguous(prevRHS, curRHS))
        {
            break;
        }

        remainingAssignments--;
        prevLHS = curLHS;
        prevRHS = curRHS;

        lastStmt = curStmt;
        curStmt = curStmt->gtNext;
    }

    if (remainingAssignments > 0)
    {
        // if the left assignments number is bigger than zero, then this means 
        // that the assignments are not assgining to the contiguously memory 
        // locations from same vector. 
        return false; 
    }
#ifdef DEBUG
    if (verbose)
    {
        printf("\nFound contiguous assignments from a SIMD vector to memory.\n");
        printf("From BB%02u, stmt", block->bbNum);
        printTreeID(stmt);
        printf(" to stmt");
        printTreeID(lastStmt);
        printf("\n");
    }
#endif  


    for (int i = 0; i < assignmentsCount; i++)
    {
        fgRemoveStmt(block, stmt->gtNext);
    }
    
    GenTree* copyBlkDst = createAddressNodeForSIMDInit(originalLHS, simdSize);
    if (simdStructNode->OperIsLocal())
    {
        setLclRelatedToSIMDIntrinsic(simdStructNode);
    }
    GenTree* copyBlkAddr = copyBlkDst;
    if (copyBlkAddr->gtOper == GT_LEA)
    {
        copyBlkAddr = copyBlkAddr->AsAddrMode()->Base();
    }
    GenTreeLclVarCommon* localDst = nullptr;
    if (copyBlkAddr->IsLocalAddrExpr(this, &localDst, nullptr))
    {
        setLclRelatedToSIMDIntrinsic(localDst);
    }

    GenTree* simdStructAddr;
    if (simdStructNode->TypeGet() == TYP_BYREF)
    {
        assert(simdStructNode->OperIsLocal());
        assert(lvaIsImplicitByRefLocal(simdStructNode->AsLclVarCommon()->gtLclNum));
        simdStructAddr = simdStructNode;
    }
    else
    {
        assert(varTypeIsSIMD(simdStructNode));
        simdStructAddr = gtNewOperNode(GT_ADDR, TYP_BYREF, simdStructNode);
    }

#ifdef DEBUG
    if (verbose)
    {
        printf("\nBB%02u stmt", block->bbNum);
        printTreeID(stmt);
        printf("(before)\n");
        gtDispTree(stmt);
    }
#endif   

    tree = gtNewBlkOpNode(GT_COPYBLK,
                        copyBlkDst,
                        simdStructAddr,
                        gtNewIconNode(simdSize),
                        false);

    stmt->gtStmt.gtStmtExpr = tree;
    
    // Since we generated a new address node which didn't exist before,
    // we should expose this address manually here.
    AXCStack stk(this);
    stk.Push(AXC_None); 
    fgWalkTree(&stmt->gtStmt.gtStmtExpr,
        fgMarkAddrTakenLocalsPreCB,
        fgMarkAddrTakenLocalsPostCB,
        &stk);

#ifdef DEBUG
    if (verbose)
    {
        printf("\nReplaced BB%02u stmt", block->bbNum);
        printTreeID(stmt);
        printf("(after)\n");
        gtDispTree(stmt);
    }
#endif    
    return true;
}

#endif //FEATURE_SIMD