// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
-//
-// This is the LLVM loop vectorizer. This pass modifies 'vectorizable' loops
-// and generates target-independent LLVM-IR. Legalization of the IR is done
-// in the codegen. However, the vectorizes uses (will use) the codegen
-// interfaces to generate IR that is likely to result in an optimal binary.
-//
-// The loop vectorizer combines consecutive loop iteration into a single
-// 'wide' iteration. After this transformation the index is incremented
-// by the SIMD vector width, and not by one.
-//
-// This pass has three parts:
-// 1. The main loop pass that drives the different parts.
-// 2. LoopVectorizationLegality - A unit that checks for the legality
-// of the vectorization.
-// 3. InnerLoopVectorizer - A unit that performs the actual
-// widening of instructions.
-// 4. LoopVectorizationCostModel - A unit that checks for the profitability
-// of vectorization. It decides on the optimal vector width, which
-// can be one, if vectorization is not profitable.
-//
-//===----------------------------------------------------------------------===//
-//
-// The reduction-variable vectorization is based on the paper:
-// D. Nuzman and R. Henderson. Multi-platform Auto-vectorization.
-//
-// Variable uniformity checks are inspired by:
-// Karrenberg, R. and Hack, S. Whole Function Vectorization.
-//
-// Other ideas/concepts are from:
-// A. Zaks and D. Nuzman. Autovectorization in GCC-two years later.
-//
-// S. Maleki, Y. Gao, M. Garzaran, T. Wong and D. Padua. An Evaluation of
-// Vectorizing Compilers.
-//
-//===----------------------------------------------------------------------===//
-#define LV_NAME "loop-vectorize"
-#define DEBUG_TYPE LV_NAME
-#include "llvm/Transforms/Vectorize.h"
-#include "llvm/ADT/SmallVector.h"
+#include "LoopVectorize.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopIterator.h"
#include "llvm/Analysis/LoopPass.h"
-#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Vectorize.h"
#include "llvm/Type.h"
#include "llvm/Value.h"
-#include <algorithm>
-using namespace llvm;
static cl::opt<unsigned>
VectorizationFactor("force-vector-width", cl::init(0), cl::Hidden,
- cl::desc("Set the default vectorization width. Zero is autoselect."));
+ cl::desc("Sets the SIMD width. Zero is autoselect."));
static cl::opt<bool>
EnableIfConversion("enable-if-conversion", cl::init(true), cl::Hidden,
cl::desc("Enable if-conversion during vectorization."));
-/// We don't vectorize loops with a known constant trip count below this number.
-const unsigned TinyTripCountThreshold = 16;
-
-/// When performing a runtime memory check, do not check more than this
-/// number of pointers. Notice that the check is quadratic!
-const unsigned RuntimeMemoryCheckThreshold = 4;
-
-/// This is the highest vector width that we try to generate.
-const unsigned MaxVectorSize = 8;
-
namespace {
-// Forward declarations.
-class LoopVectorizationLegality;
-class LoopVectorizationCostModel;
-
-/// InnerLoopVectorizer vectorizes loops which contain only one basic
-/// block to a specified vectorization factor (VF).
-/// This class performs the widening of scalars into vectors, or multiple
-/// scalars. This class also implements the following features:
-/// * It inserts an epilogue loop for handling loops that don't have iteration
-/// counts that are known to be a multiple of the vectorization factor.
-/// * It handles the code generation for reduction variables.
-/// * Scalarization (implementation using scalars) of un-vectorizable
-/// instructions.
-/// InnerLoopVectorizer does not perform any vectorization-legality
-/// checks, and relies on the caller to check for the different legality
-/// aspects. The InnerLoopVectorizer relies on the
-/// LoopVectorizationLegality class to provide information about the induction
-/// and reduction variables that were found to a given vectorization factor.
-class InnerLoopVectorizer {
-public:
- /// Ctor.
- InnerLoopVectorizer(Loop *Orig, ScalarEvolution *Se, LoopInfo *Li,
- DominatorTree *Dt, DataLayout *Dl, unsigned VecWidth):
- OrigLoop(Orig), SE(Se), LI(Li), DT(Dt), DL(Dl), VF(VecWidth),
- Builder(Se->getContext()), Induction(0), OldInduction(0) { }
-
- // Perform the actual loop widening (vectorization).
- void vectorize(LoopVectorizationLegality *Legal) {
- // Create a new empty loop. Unlink the old loop and connect the new one.
- createEmptyLoop(Legal);
- // Widen each instruction in the old loop to a new one in the new loop.
- // Use the Legality module to find the induction and reduction variables.
- vectorizeLoop(Legal);
- // Register the new loop and update the analysis passes.
- updateAnalysis();
- }
-
-private:
- /// A small list of PHINodes.
- typedef SmallVector<PHINode*, 4> PhiVector;
-
- /// Add code that checks at runtime if the accessed arrays overlap.
- /// Returns the comparator value or NULL if no check is needed.
- Value *addRuntimeCheck(LoopVectorizationLegality *Legal,
- Instruction *Loc);
- /// Create an empty loop, based on the loop ranges of the old loop.
- void createEmptyLoop(LoopVectorizationLegality *Legal);
- /// Copy and widen the instructions from the old loop.
- void vectorizeLoop(LoopVectorizationLegality *Legal);
-
- /// A helper function that computes the predicate of the block BB, assuming
- /// that the header block of the loop is set to True. It returns the *entry*
- /// mask for the block BB.
- Value *createBlockInMask(BasicBlock *BB);
- /// A helper function that computes the predicate of the edge between SRC
- /// and DST.
- Value *createEdgeMask(BasicBlock *Src, BasicBlock *Dst);
-
- /// A helper function to vectorize a single BB within the innermost loop.
- void vectorizeBlockInLoop(LoopVectorizationLegality *Legal, BasicBlock *BB,
- PhiVector *PV);
-
- /// Insert the new loop to the loop hierarchy and pass manager
- /// and update the analysis passes.
- void updateAnalysis();
-
- /// This instruction is un-vectorizable. Implement it as a sequence
- /// of scalars.
- void scalarizeInstruction(Instruction *Instr);
-
- /// Create a broadcast instruction. This method generates a broadcast
- /// instruction (shuffle) for loop invariant values and for the induction
- /// value. If this is the induction variable then we extend it to N, N+1, ...
- /// this is needed because each iteration in the loop corresponds to a SIMD
- /// element.
- Value *getBroadcastInstrs(Value *V);
-
- /// This function adds 0, 1, 2 ... to each vector element, starting at zero.
- /// If Negate is set then negative numbers are added e.g. (0, -1, -2, ...).
- Value *getConsecutiveVector(Value* Val, bool Negate = false);
-
- /// When we go over instructions in the basic block we rely on previous
- /// values within the current basic block or on loop invariant values.
- /// When we widen (vectorize) values we place them in the map. If the values
- /// are not within the map, they have to be loop invariant, so we simply
- /// broadcast them into a vector.
- Value *getVectorValue(Value *V);
-
- /// Get a uniform vector of constant integers. We use this to get
- /// vectors of ones and zeros for the reduction code.
- Constant* getUniformVector(unsigned Val, Type* ScalarTy);
-
- typedef DenseMap<Value*, Value*> ValueMap;
-
- /// The original loop.
- Loop *OrigLoop;
- // Scev analysis to use.
- ScalarEvolution *SE;
- // Loop Info.
- LoopInfo *LI;
- // Dominator Tree.
- DominatorTree *DT;
- // Data Layout.
- DataLayout *DL;
- // The vectorization factor to use.
- unsigned VF;
-
- // The builder that we use
- IRBuilder<> Builder;
-
- // --- Vectorization state ---
-
- /// The vector-loop preheader.
- BasicBlock *LoopVectorPreHeader;
- /// The scalar-loop preheader.
- BasicBlock *LoopScalarPreHeader;
- /// Middle Block between the vector and the scalar.
- BasicBlock *LoopMiddleBlock;
- ///The ExitBlock of the scalar loop.
- BasicBlock *LoopExitBlock;
- ///The vector loop body.
- BasicBlock *LoopVectorBody;
- ///The scalar loop body.
- BasicBlock *LoopScalarBody;
- ///The first bypass block.
- BasicBlock *LoopBypassBlock;
-
- /// The new Induction variable which was added to the new block.
- PHINode *Induction;
- /// The induction variable of the old basic block.
- PHINode *OldInduction;
- // Maps scalars to widened vectors.
- ValueMap WidenMap;
-};
-
-/// LoopVectorizationLegality checks if it is legal to vectorize a loop, and
-/// to what vectorization factor.
-/// This class does not look at the profitability of vectorization, only the
-/// legality. This class has two main kinds of checks:
-/// * Memory checks - The code in canVectorizeMemory checks if vectorization
-/// will change the order of memory accesses in a way that will change the
-/// correctness of the program.
-/// * Scalars checks - The code in canVectorizeInstrs and canVectorizeMemory
-/// checks for a number of different conditions, such as the availability of a
-/// single induction variable, that all types are supported and vectorize-able,
-/// etc. This code reflects the capabilities of InnerLoopVectorizer.
-/// This class is also used by InnerLoopVectorizer for identifying
-/// induction variable and the different reduction variables.
-class LoopVectorizationLegality {
-public:
- LoopVectorizationLegality(Loop *Lp, ScalarEvolution *Se, DataLayout *Dl,
- DominatorTree *Dt):
- TheLoop(Lp), SE(Se), DL(Dl), DT(Dt), Induction(0) { }
-
- /// This enum represents the kinds of reductions that we support.
- enum ReductionKind {
- NoReduction, /// Not a reduction.
- IntegerAdd, /// Sum of numbers.
- IntegerMult, /// Product of numbers.
- IntegerOr, /// Bitwise or logical OR of numbers.
- IntegerAnd, /// Bitwise or logical AND of numbers.
- IntegerXor /// Bitwise or logical XOR of numbers.
- };
-
- /// This enum represents the kinds of inductions that we support.
- enum InductionKind {
- NoInduction, /// Not an induction variable.
- IntInduction, /// Integer induction variable. Step = 1.
- ReverseIntInduction, /// Reverse int induction variable. Step = -1.
- PtrInduction /// Pointer induction variable. Step = sizeof(elem).
- };
-
- /// This POD struct holds information about reduction variables.
- struct ReductionDescriptor {
- // Default C'tor
- ReductionDescriptor():
- StartValue(0), LoopExitInstr(0), Kind(NoReduction) {}
-
- // C'tor.
- ReductionDescriptor(Value *Start, Instruction *Exit, ReductionKind K):
- StartValue(Start), LoopExitInstr(Exit), Kind(K) {}
-
- // The starting value of the reduction.
- // It does not have to be zero!
- Value *StartValue;
- // The instruction who's value is used outside the loop.
- Instruction *LoopExitInstr;
- // The kind of the reduction.
- ReductionKind Kind;
- };
-
- // This POD struct holds information about the memory runtime legality
- // check that a group of pointers do not overlap.
- struct RuntimePointerCheck {
- RuntimePointerCheck(): Need(false) {}
-
- /// Reset the state of the pointer runtime information.
- void reset() {
- Need = false;
- Pointers.clear();
- Starts.clear();
- Ends.clear();
- }
-
- /// Insert a pointer and calculate the start and end SCEVs.
- void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr) {
- const SCEV *Sc = SE->getSCEV(Ptr);
- const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc);
- assert(AR && "Invalid addrec expression");
- const SCEV *Ex = SE->getExitCount(Lp, Lp->getLoopLatch());
- const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE);
- Pointers.push_back(Ptr);
- Starts.push_back(AR->getStart());
- Ends.push_back(ScEnd);
- }
-
- /// This flag indicates if we need to add the runtime check.
- bool Need;
- /// Holds the pointers that we need to check.
- SmallVector<Value*, 2> Pointers;
- /// Holds the pointer value at the beginning of the loop.
- SmallVector<const SCEV*, 2> Starts;
- /// Holds the pointer value at the end of the loop.
- SmallVector<const SCEV*, 2> Ends;
- };
-
- /// A POD for saving information about induction variables.
- struct InductionInfo {
- /// Ctors.
- InductionInfo(Value *Start, InductionKind K):
- StartValue(Start), IK(K) {};
- InductionInfo(): StartValue(0), IK(NoInduction) {};
- /// Start value.
- Value *StartValue;
- /// Induction kind.
- InductionKind IK;
- };
-
- /// ReductionList contains the reduction descriptors for all
- /// of the reductions that were found in the loop.
- typedef DenseMap<PHINode*, ReductionDescriptor> ReductionList;
-
- /// InductionList saves induction variables and maps them to the
- /// induction descriptor.
- typedef DenseMap<PHINode*, InductionInfo> InductionList;
-
- /// Returns true if it is legal to vectorize this loop.
- /// This does not mean that it is profitable to vectorize this
- /// loop, only that it is legal to do so.
- bool canVectorize();
-
- /// Returns the Induction variable.
- PHINode *getInduction() {return Induction;}
-
- /// Returns the reduction variables found in the loop.
- ReductionList *getReductionVars() { return &Reductions; }
-
- /// Returns the induction variables found in the loop.
- InductionList *getInductionVars() { return &Inductions; }
-
- /// Return true if the block BB needs to be predicated in order for the loop
- /// to be vectorized.
- bool blockNeedsPredication(BasicBlock *BB);
-
- /// Check if this pointer is consecutive when vectorizing. This happens
- /// when the last index of the GEP is the induction variable, or that the
- /// pointer itself is an induction variable.
- /// This check allows us to vectorize A[idx] into a wide load/store.
- bool isConsecutivePtr(Value *Ptr);
-
- /// Returns true if the value V is uniform within the loop.
- bool isUniform(Value *V);
-
- /// Returns true if this instruction will remain scalar after vectorization.
- bool isUniformAfterVectorization(Instruction* I) {return Uniforms.count(I);}
-
- /// Returns the information that we collected about runtime memory check.
- RuntimePointerCheck *getRuntimePointerCheck() {return &PtrRtCheck; }
-private:
- /// Check if a single basic block loop is vectorizable.
- /// At this point we know that this is a loop with a constant trip count
- /// and we only need to check individual instructions.
- bool canVectorizeInstrs();
-
- /// When we vectorize loops we may change the order in which
- /// we read and write from memory. This method checks if it is
- /// legal to vectorize the code, considering only memory constrains.
- /// Returns true if the loop is vectorizable
- bool canVectorizeMemory();
-
- /// Return true if we can vectorize this loop using the IF-conversion
- /// transformation.
- bool canVectorizeWithIfConvert();
-
- /// Collect the variables that need to stay uniform after vectorization.
- void collectLoopUniforms();
-
- /// Return true if all of the instructions in the block can be speculatively
- /// executed.
- bool blockCanBePredicated(BasicBlock *BB);
-
- /// Returns True, if 'Phi' is the kind of reduction variable for type
- /// 'Kind'. If this is a reduction variable, it adds it to ReductionList.
- bool AddReductionVar(PHINode *Phi, ReductionKind Kind);
- /// Returns true if the instruction I can be a reduction variable of type
- /// 'Kind'.
- bool isReductionInstr(Instruction *I, ReductionKind Kind);
- /// Returns the induction kind of Phi. This function may return NoInduction
- /// if the PHI is not an induction variable.
- InductionKind isInductionVariable(PHINode *Phi);
- /// Return true if can compute the address bounds of Ptr within the loop.
- bool hasComputableBounds(Value *Ptr);
-
- /// The loop that we evaluate.
- Loop *TheLoop;
- /// Scev analysis.
- ScalarEvolution *SE;
- /// DataLayout analysis.
- DataLayout *DL;
- // Dominators.
- DominatorTree *DT;
-
- // --- vectorization state --- //
-
- /// Holds the integer induction variable. This is the counter of the
- /// loop.
- PHINode *Induction;
- /// Holds the reduction variables.
- ReductionList Reductions;
- /// Holds all of the induction variables that we found in the loop.
- /// Notice that inductions don't need to start at zero and that induction
- /// variables can be pointers.
- InductionList Inductions;
-
- /// Allowed outside users. This holds the reduction
- /// vars which can be accessed from outside the loop.
- SmallPtrSet<Value*, 4> AllowedExit;
- /// This set holds the variables which are known to be uniform after
- /// vectorization.
- SmallPtrSet<Instruction*, 4> Uniforms;
- /// We need to check that all of the pointers in this list are disjoint
- /// at runtime.
- RuntimePointerCheck PtrRtCheck;
-};
-
-/// LoopVectorizationCostModel - estimates the expected speedups due to
-/// vectorization.
-/// In many cases vectorization is not profitable. This can happen because
-/// of a number of reasons. In this class we mainly attempt to predict
-/// the expected speedup/slowdowns due to the supported instruction set.
-/// We use the VectorTargetTransformInfo to query the different backends
-/// for the cost of different operations.
-class LoopVectorizationCostModel {
-public:
- /// C'tor.
- LoopVectorizationCostModel(Loop *Lp, ScalarEvolution *Se,
- LoopVectorizationLegality *Leg,
- const VectorTargetTransformInfo *Vtti):
- TheLoop(Lp), SE(Se), Legal(Leg), VTTI(Vtti) { }
-
- /// Returns the most profitable vectorization factor for the loop that is
- /// smaller or equal to the VF argument. This method checks every power
- /// of two up to VF.
- unsigned findBestVectorizationFactor(unsigned VF = MaxVectorSize);
-
-private:
- /// Returns the expected execution cost. The unit of the cost does
- /// not matter because we use the 'cost' units to compare different
- /// vector widths. The cost that is returned is *not* normalized by
- /// the factor width.
- unsigned expectedCost(unsigned VF);
-
- /// Returns the execution time cost of an instruction for a given vector
- /// width. Vector width of one means scalar.
- unsigned getInstructionCost(Instruction *I, unsigned VF);
-
- /// A helper function for converting Scalar types to vector types.
- /// If the incoming type is void, we return void. If the VF is 1, we return
- /// the scalar type.
- static Type* ToVectorTy(Type *Scalar, unsigned VF);
-
- /// The loop that we evaluate.
- Loop *TheLoop;
- /// Scev analysis.
- ScalarEvolution *SE;
-
- /// Vectorization legality.
- LoopVectorizationLegality *Legal;
- /// Vector target information.
- const VectorTargetTransformInfo *VTTI;
-};
-
+/// The LoopVectorize Pass.
struct LoopVectorize : public LoopPass {
static char ID; // Pass identification, replacement for typeid
};
+}// namespace
+
+//===----------------------------------------------------------------------===//
+// Implementation of LoopVectorizationLegality, InnerLoopVectorizer and
+// LoopVectorizationCostModel.
+//===----------------------------------------------------------------------===//
+
+void
+LoopVectorizationLegality::RuntimePointerCheck::insert(ScalarEvolution *SE,
+ Loop *Lp, Value *Ptr) {
+ const SCEV *Sc = SE->getSCEV(Ptr);
+ const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc);
+ assert(AR && "Invalid addrec expression");
+ const SCEV *Ex = SE->getExitCount(Lp, Lp->getLoopLatch());
+ const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE);
+ Pointers.push_back(Ptr);
+ Starts.push_back(AR->getStart());
+ Ends.push_back(ScEnd);
+}
+
Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) {
// Create the types.
LLVMContext &C = V->getContext();
Value *SingleElem = Builder.CreateInsertElement(UndefVal, V, Zero);
// Broadcast the scalar into all locations in the vector.
Value *Shuf = Builder.CreateShuffleVector(SingleElem, UndefVal, Zeros,
- "broadcast");
+ "broadcast");
// Restore the builder insertion point.
if (Invariant)
InnerLoopVectorizer::addRuntimeCheck(LoopVectorizationLegality *Legal,
Instruction *Loc) {
LoopVectorizationLegality::RuntimePointerCheck *PtrRtCheck =
- Legal->getRuntimePointerCheck();
+ Legal->getRuntimePointerCheck();
if (!PtrRtCheck->Need)
return NULL;
the vectorized instructions while the old loop will continue to run the
scalar remainder.
- [ ] <-- vector loop bypass.
- / |
- / v
-| [ ] <-- vector pre header.
-| |
-| v
-| [ ] \
-| [ ]_| <-- vector loop.
-| |
- \ v
+ [ ] <-- vector loop bypass.
+ / |
+ / v
+ | [ ] <-- vector pre header.
+ | |
+ | v
+ | [ ] \
+ | [ ]_| <-- vector loop.
+ | |
+ \ v
>[ ] <--- middle-block.
- / |
- / v
-| [ ] <--- new preheader.
-| |
-| v
-| [ ] \
-| [ ]_| <-- old scalar loop to handle remainder.
- \ |
- \ v
+ / |
+ / v
+ | [ ] <--- new preheader.
+ | |
+ | v
+ | [ ] \
+ | [ ]_| <-- old scalar loop to handle remainder.
+ \ |
+ \ v
>[ ] <-- exit block.
...
*/
// don't have a single induction variable.
OldInduction = Legal->getInduction();
Type *IdxTy = OldInduction ? OldInduction->getType() :
- DL->getIntPtrType(SE->getContext());
+ DL->getIntPtrType(SE->getContext());
// Find the loop boundaries.
const SCEV *ExitCount = SE->getExitCount(OrigLoop, OrigLoop->getLoopLatch());
// value from the induction PHI node. If we don't have an induction variable
// then we know that it starts at zero.
Value *StartIdx = OldInduction ?
- OldInduction->getIncomingValueForBlock(BypassBlock):
- ConstantInt::get(IdxTy, 0);
+ OldInduction->getIncomingValueForBlock(BypassBlock):
+ ConstantInt::get(IdxTy, 0);
assert(BypassBlock && "Invalid loop structure");
// Split the single block loop into the two loop structure described above.
BasicBlock *VectorPH =
- BypassBlock->splitBasicBlock(BypassBlock->getTerminator(), "vector.ph");
+ BypassBlock->splitBasicBlock(BypassBlock->getTerminator(), "vector.ph");
BasicBlock *VecBody =
- VectorPH->splitBasicBlock(VectorPH->getTerminator(), "vector.body");
+ VectorPH->splitBasicBlock(VectorPH->getTerminator(), "vector.body");
BasicBlock *MiddleBlock =
- VecBody->splitBasicBlock(VecBody->getTerminator(), "middle.block");
+ VecBody->splitBasicBlock(VecBody->getTerminator(), "middle.block");
BasicBlock *ScalarPH =
- MiddleBlock->splitBasicBlock(MiddleBlock->getTerminator(), "scalar.ph");
+ MiddleBlock->splitBasicBlock(MiddleBlock->getTerminator(), "scalar.ph");
// This is the location in which we add all of the logic for bypassing
// the new vector loop.
// PHIs that are left in the scalar version of the loop.
// The starting values of PHI nodes depend on the counter of the last
// iteration in the vectorized loop.
- // If we come from a bypass edge then we need to start from the original start
- // value.
+ // If we come from a bypass edge then we need to start from the original
+ // start value.
// This variable saves the new starting index for the scalar loop.
PHINode *ResumeIndex = 0;
PHINode *OrigPhi = I->first;
LoopVectorizationLegality::InductionInfo II = I->second;
PHINode *ResumeVal = PHINode::Create(OrigPhi->getType(), 2, "resume.val",
- MiddleBlock->getTerminator());
+ MiddleBlock->getTerminator());
Value *EndValue = 0;
switch (II.IK) {
case LoopVectorizationLegality::NoInduction:
//
//===------------------------------------------------===//
BasicBlock &BB = *OrigLoop->getHeader();
- Constant *Zero = ConstantInt::get(
- IntegerType::getInt32Ty(BB.getContext()), 0);
+ Constant *Zero =
+ ConstantInt::get(IntegerType::getInt32Ty(BB.getContext()), 0);
// In order to support reduction variables we need to be able to vectorize
// Phi nodes. Phi nodes have cycles, so we need to vectorize them in two
assert(Legal->getReductionVars()->count(RdxPhi) &&
"Unable to find the reduction variable");
LoopVectorizationLegality::ReductionDescriptor RdxDesc =
- (*Legal->getReductionVars())[RdxPhi];
+ (*Legal->getReductionVars())[RdxPhi];
// We need to generate a reduction vector from the incoming scalar.
// To do so, we need to generate the 'identity' vector and overide
// This vector is the Identity vector where the first element is the
// incoming scalar reduction.
Value *VectorStart = Builder.CreateInsertElement(Identity,
- RdxDesc.StartValue, Zero);
+ RdxDesc.StartValue, Zero);
// Fix the vector-loop phi.
// We created the induction variable so we know that the
// Extract the first scalar.
Value *Scalar0 =
- Builder.CreateExtractElement(NewPhi, Builder.getInt32(0));
+ Builder.CreateExtractElement(NewPhi, Builder.getInt32(0));
// Extract and reduce the remaining vector elements.
for (unsigned i=1; i < VF; ++i) {
Value *Scalar1 =
- Builder.CreateExtractElement(NewPhi, Builder.getInt32(i));
+ Builder.CreateExtractElement(NewPhi, Builder.getInt32(i));
switch (RdxDesc.Kind) {
- case LoopVectorizationLegality::IntegerAdd:
- Scalar0 = Builder.CreateAdd(Scalar0, Scalar1, "add.rdx");
- break;
- case LoopVectorizationLegality::IntegerMult:
- Scalar0 = Builder.CreateMul(Scalar0, Scalar1, "mul.rdx");
- break;
- case LoopVectorizationLegality::IntegerOr:
- Scalar0 = Builder.CreateOr(Scalar0, Scalar1, "or.rdx");
- break;
- case LoopVectorizationLegality::IntegerAnd:
- Scalar0 = Builder.CreateAnd(Scalar0, Scalar1, "and.rdx");
- break;
- case LoopVectorizationLegality::IntegerXor:
- Scalar0 = Builder.CreateXor(Scalar0, Scalar1, "xor.rdx");
- break;
- default:
- llvm_unreachable("Unknown reduction operation");
+ case LoopVectorizationLegality::IntegerAdd:
+ Scalar0 = Builder.CreateAdd(Scalar0, Scalar1, "add.rdx");
+ break;
+ case LoopVectorizationLegality::IntegerMult:
+ Scalar0 = Builder.CreateMul(Scalar0, Scalar1, "mul.rdx");
+ break;
+ case LoopVectorizationLegality::IntegerOr:
+ Scalar0 = Builder.CreateOr(Scalar0, Scalar1, "or.rdx");
+ break;
+ case LoopVectorizationLegality::IntegerAnd:
+ Scalar0 = Builder.CreateAnd(Scalar0, Scalar1, "and.rdx");
+ break;
+ case LoopVectorizationLegality::IntegerXor:
+ Scalar0 = Builder.CreateXor(Scalar0, Scalar1, "xor.rdx");
+ break;
+ default:
+ llvm_unreachable("Unknown reduction operation");
}
}
assert(OrigLoop->contains(BB) && "Block is not a part of a loop");
// Loop incoming mask is all-one.
- if (OrigLoop->getHeader() == BB)
- return getVectorValue(
- ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 1));
+ if (OrigLoop->getHeader() == BB) {
+ Value *C = ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 1);
+ return getVectorValue(C);
+ }
// This is the block mask. We OR all incoming edges, and with zero.
- Value *BlockMask = getVectorValue(
- ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 0));
+ Value *Zero = ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 0);
+ Value *BlockMask = getVectorValue(Zero);
// For each pred:
for (pred_iterator it = pred_begin(BB), e = pred_end(BB); it != e; ++it)
// For each instruction in the old loop.
for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) {
switch (it->getOpcode()) {
- case Instruction::Br:
- // Nothing to do for PHIs and BR, since we already took care of the
- // loop control flow instructions.
- continue;
- case Instruction::PHI:{
-
PHINode* P = cast<PHINode>(it);
- // Handle reduction variables:
- if (Legal->getReductionVars()->count(P)) {
- // This is phase one of vectorizing PHIs.
- Type *VecTy = VectorType::get(it->getType(), VF);
- WidenMap[it] =
+ case Instruction::Br:
+ // Nothing to do for PHIs and BR, since we already took care of the
+ // loop control flow instructions.
+ continue;
+ case Instruction::PHI:{
+ PHINode* P = cast<PHINode>(it);
+ // Handle reduction variables:
+ if (Legal->getReductionVars()->count(P)) {
+ // This is phase one of vectorizing PHIs.
+ Type *VecTy = VectorType::get(it->getType(), VF);
+ WidenMap[it] =
PHINode::Create(VecTy, 2, "vec.phi",
LoopVectorBody->getFirstInsertionPt());
- PV->push_back(P);
- continue;
- }
-
- // Check for PHI nodes that are lowered to vector selects.
- if (P->getParent() != OrigLoop->getHeader()) {
- // We know that all PHIs in non header blocks are converted into
- // selects, so we don't have to worry about the insertion order and we
- // can just use the builder.
-
- // At this point we generate the predication tree. There may be
- // duplications since this is a simple recursive scan, but future
- // optimizations will clean it up.
- Value *Cond = createBlockInMask(P->getIncomingBlock(0));
- WidenMap[P] =
- Builder.CreateSelect(Cond,
- getVectorValue(P->getIncomingValue(0)),
- getVectorValue(P->getIncomingValue(1)),
- "predphi");
- continue;
- }
-
- // This PHINode must be an induction variable.
- // Make sure that we know about it.
- assert(Legal->getInductionVars()->count(P) &&
- "Not an induction variable");
+ PV->push_back(P);
+ continue;
+ }
- LoopVectorizationLegality::InductionInfo II =
- Legal->getInductionVars()->lookup(P);
+ // Check for PHI nodes that are lowered to vector selects.
+ if (P->getParent() != OrigLoop->getHeader()) {
+ // We know that all PHIs in non header blocks are converted into
+ // selects, so we don't have to worry about the insertion order and we
+ // can just use the builder.
+
+ // At this point we generate the predication tree. There may be
+ // duplications since this is a simple recursive scan, but future
+ // optimizations will clean it up.
+ Value *Cond = createBlockInMask(P->getIncomingBlock(0));
+ WidenMap[P] =
+ Builder.CreateSelect(Cond,
+ getVectorValue(P->getIncomingValue(0)),
+ getVectorValue(P->getIncomingValue(1)),
+ "predphi");
+ continue;
+ }
- switch (II.IK) {
- case LoopVectorizationLegality::NoInduction:
- llvm_unreachable("Unknown induction");
- case LoopVectorizationLegality::IntInduction: {
- assert(P == OldInduction && "Unexpected PHI");
- Value *Broadcasted = getBroadcastInstrs(Induction);
+ // This PHINode must be an induction variable.
+ // Make sure that we know about it.
+ assert(Legal->getInductionVars()->count(P) &&
+ "Not an induction variable");
+
+ LoopVectorizationLegality::InductionInfo II =
+ Legal->getInductionVars()->lookup(P);
+
+ switch (II.IK) {
+ case LoopVectorizationLegality::NoInduction:
+ llvm_unreachable("Unknown induction");
+ case LoopVectorizationLegality::IntInduction: {
+ assert(P == OldInduction && "Unexpected PHI");
+ Value *Broadcasted = getBroadcastInstrs(Induction);
+ // After broadcasting the induction variable we need to make the
+ // vector consecutive by adding 0, 1, 2 ...
+ Value *ConsecutiveInduction = getConsecutiveVector(Broadcasted);
+ WidenMap[OldInduction] = ConsecutiveInduction;
+ continue;
+ }
+ case LoopVectorizationLegality::ReverseIntInduction:
+ case LoopVectorizationLegality::PtrInduction:
+ // Handle reverse integer and pointer inductions.
+ Value *StartIdx = 0;
+ // If we have a single integer induction variable then use it.
+ // Otherwise, start counting at zero.
+ if (OldInduction) {
+ LoopVectorizationLegality::InductionInfo OldII =
+ Legal->getInductionVars()->lookup(OldInduction);
+ StartIdx = OldII.StartValue;
+ } else {
+ StartIdx = ConstantInt::get(Induction->getType(), 0);
+ }
+ // This is the normalized GEP that starts counting at zero.
+ Value *NormalizedIdx = Builder.CreateSub(Induction, StartIdx,
+ "normalized.idx");
+
+ // Handle the reverse integer induction variable case.
+ if (LoopVectorizationLegality::ReverseIntInduction == II.IK) {
+ IntegerType *DstTy = cast<IntegerType>(II.StartValue->getType());
+ Value *CNI = Builder.CreateSExtOrTrunc(NormalizedIdx, DstTy,
+ "resize.norm.idx");
+ Value *ReverseInd = Builder.CreateSub(II.StartValue, CNI,
+ "reverse.idx");
+
+ // This is a new value so do not hoist it out.
+ Value *Broadcasted = getBroadcastInstrs(ReverseInd);
// After broadcasting the induction variable we need to make the
- // vector consecutive by adding 0, 1, 2 ...
- Value *ConsecutiveInduction = getConsecutiveVector(Broadcasted);
- WidenMap[OldInduction] = ConsecutiveInduction;
+ // vector consecutive by adding ... -3, -2, -1, 0.
+ Value *ConsecutiveInduction = getConsecutiveVector(Broadcasted,
+ true);
+ WidenMap[it] = ConsecutiveInduction;
continue;
}
- case LoopVectorizationLegality::ReverseIntInduction:
- case LoopVectorizationLegality::PtrInduction:
- // Handle reverse integer and pointer inductions.
- Value *StartIdx = 0;
- // If we have a single integer induction variable then use it.
- // Otherwise, start counting at zero.
- if (OldInduction) {
- LoopVectorizationLegality::InductionInfo OldII =
- Legal->getInductionVars()->lookup(OldInduction);
- StartIdx = OldII.StartValue;
- } else {
- StartIdx = ConstantInt::get(Induction->getType(), 0);
- }
- // This is the normalized GEP that starts counting at zero.
- Value *NormalizedIdx = Builder.CreateSub(Induction, StartIdx,
- "normalized.idx");
-
- // Handle the reverse integer induction variable case.
- if (LoopVectorizationLegality::ReverseIntInduction == II.IK) {
- IntegerType *DstTy = cast<IntegerType>(II.StartValue->getType());
- Value *CNI = Builder.CreateSExtOrTrunc(NormalizedIdx, DstTy,
- "resize.norm.idx");
- Value *ReverseInd = Builder.CreateSub(II.StartValue, CNI,
- "reverse.idx");
-
- // This is a new value so do not hoist it out.
- Value *Broadcasted = getBroadcastInstrs(ReverseInd);
- // After broadcasting the induction variable we need to make the
- // vector consecutive by adding ... -3, -2, -1, 0.
- Value *ConsecutiveInduction = getConsecutiveVector(Broadcasted,
- true);
- WidenMap[it] = ConsecutiveInduction;
- continue;
- }
-
- // Handle the pointer induction variable case.
- assert(P->getType()->isPointerTy() && "Unexpected type.");
-
- // This is the vector of results. Notice that we don't generate vector
- // geps because scalar geps result in better code.
- Value *VecVal = UndefValue::get(VectorType::get(P->getType(), VF));
- for (unsigned int i = 0; i < VF; ++i) {
- Constant *Idx = ConstantInt::get(Induction->getType(), i);
- Value *GlobalIdx = Builder.CreateAdd(NormalizedIdx, Idx, "gep.idx");
- Value *SclrGep = Builder.CreateGEP(II.StartValue, GlobalIdx, "next.gep");
- VecVal = Builder.CreateInsertElement(VecVal, SclrGep,
- Builder.getInt32(i),
- "insert.gep");
- }
- WidenMap[it] = VecVal;
- continue;
+ // Handle the pointer induction variable case.
+ assert(P->getType()->isPointerTy() && "Unexpected type.");
+
+ // This is the vector of results. Notice that we don't generate
+ // vector geps because scalar geps result in better code.
+ Value *VecVal = UndefValue::get(VectorType::get(P->getType(), VF));
+ for (unsigned int i = 0; i < VF; ++i) {
+ Constant *Idx = ConstantInt::get(Induction->getType(), i);
+ Value *GlobalIdx = Builder.CreateAdd(NormalizedIdx, Idx,
+ "gep.idx");
+ Value *SclrGep = Builder.CreateGEP(II.StartValue, GlobalIdx,
+ "next.gep");
+ VecVal = Builder.CreateInsertElement(VecVal, SclrGep,
+ Builder.getInt32(i),
+ "insert.gep");
}
- }// End of PHI.
-
- case Instruction::Add:
- case Instruction::FAdd:
- case Instruction::Sub:
- case Instruction::FSub:
- case Instruction::Mul:
- case Instruction::FMul:
- case Instruction::UDiv:
- case Instruction::SDiv:
- case Instruction::FDiv:
- case Instruction::URem:
- case Instruction::SRem:
- case Instruction::FRem:
- case Instruction::Shl:
- case Instruction::LShr:
- case Instruction::AShr:
- case Instruction::And:
- case Instruction::Or:
- case Instruction::Xor: {
- // Just widen binops.
- BinaryOperator *BinOp = dyn_cast<BinaryOperator>(it);
- Value *A = getVectorValue(it->getOperand(0));
- Value *B = getVectorValue(it->getOperand(1));
-
- // Use this vector value for all users of the original instruction.
- Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A, B);
- WidenMap[it] = V;
-
- // Update the NSW, NUW and Exact flags.
- BinaryOperator *VecOp = cast<BinaryOperator>(V);
- if (isa<OverflowingBinaryOperator>(BinOp)) {
- VecOp->setHasNoSignedWrap(BinOp->hasNoSignedWrap());
- VecOp->setHasNoUnsignedWrap(BinOp->hasNoUnsignedWrap());
- }
- if (isa<PossiblyExactOperator>(VecOp))
- VecOp->setIsExact(BinOp->isExact());
- break;
- }
- case Instruction::Select: {
- // Widen selects.
- // If the selector is loop invariant we can create a select
- // instruction with a scalar condition. Otherwise, use vector-select.
- Value *Cond = it->getOperand(0);
- bool InvariantCond = SE->isLoopInvariant(SE->getSCEV(Cond), OrigLoop);
-
- // The condition can be loop invariant but still defined inside the
- // loop. This means that we can't just use the original 'cond' value.
- // We have to take the 'vectorized' value and pick the first lane.
- // Instcombine will make this a no-op.
- Cond = getVectorValue(Cond);
- if (InvariantCond)
- Cond = Builder.CreateExtractElement(Cond, Builder.getInt32(0));
-
- Value *Op0 = getVectorValue(it->getOperand(1));
- Value *Op1 = getVectorValue(it->getOperand(2));
- WidenMap[it] = Builder.CreateSelect(Cond, Op0, Op1);
- break;
+ WidenMap[it] = VecVal;
+ continue;
}
- case Instruction::ICmp:
- case Instruction::FCmp: {
- // Widen compares. Generate vector compares.
- bool FCmp = (it->getOpcode() == Instruction::FCmp);
- CmpInst *Cmp = dyn_cast<CmpInst>(it);
- Value *A = getVectorValue(it->getOperand(0));
- Value *B = getVectorValue(it->getOperand(1));
- if (FCmp)
- WidenMap[it] = Builder.CreateFCmp(Cmp->getPredicate(), A, B);
- else
- WidenMap[it] = Builder.CreateICmp(Cmp->getPredicate(), A, B);
- break;
+ }// End of PHI.
+
+ case Instruction::Add:
+ case Instruction::FAdd:
+ case Instruction::Sub:
+ case Instruction::FSub:
+ case Instruction::Mul:
+ case Instruction::FMul:
+ case Instruction::UDiv:
+ case Instruction::SDiv:
+ case Instruction::FDiv:
+ case Instruction::URem:
+ case Instruction::SRem:
+ case Instruction::FRem:
+ case Instruction::Shl:
+ case Instruction::LShr:
+ case Instruction::AShr:
+ case Instruction::And:
+ case Instruction::Or:
+ case Instruction::Xor: {
+ // Just widen binops.
+ BinaryOperator *BinOp = dyn_cast<BinaryOperator>(it);
+ Value *A = getVectorValue(it->getOperand(0));
+ Value *B = getVectorValue(it->getOperand(1));
+
+ // Use this vector value for all users of the original instruction.
+ Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A, B);
+ WidenMap[it] = V;
+
+ // Update the NSW, NUW and Exact flags.
+ BinaryOperator *VecOp = cast<BinaryOperator>(V);
+ if (isa<OverflowingBinaryOperator>(BinOp)) {
+ VecOp->setHasNoSignedWrap(BinOp->hasNoSignedWrap());
+ VecOp->setHasNoUnsignedWrap(BinOp->hasNoUnsignedWrap());
}
+ if (isa<PossiblyExactOperator>(VecOp))
+ VecOp->setIsExact(BinOp->isExact());
+ break;
+ }
+ case Instruction::Select: {
+ // Widen selects.
+ // If the selector is loop invariant we can create a select
+ // instruction with a scalar condition. Otherwise, use vector-select.
+ Value *Cond = it->getOperand(0);
+ bool InvariantCond = SE->isLoopInvariant(SE->getSCEV(Cond), OrigLoop);
+
+ // The condition can be loop invariant but still defined inside the
+ // loop. This means that we can't just use the original 'cond' value.
+ // We have to take the 'vectorized' value and pick the first lane.
+ // Instcombine will make this a no-op.
+ Cond = getVectorValue(Cond);
+ if (InvariantCond)
+ Cond = Builder.CreateExtractElement(Cond, Builder.getInt32(0));
+
+ Value *Op0 = getVectorValue(it->getOperand(1));
+ Value *Op1 = getVectorValue(it->getOperand(2));
+ WidenMap[it] = Builder.CreateSelect(Cond, Op0, Op1);
+ break;
+ }
- case Instruction::Store: {
- // Attempt to issue a wide store.
- StoreInst *SI = dyn_cast<StoreInst>(it);
- Type *StTy = VectorType::get(SI->getValueOperand()->getType(), VF);
- Value *Ptr = SI->getPointerOperand();
- unsigned Alignment = SI->getAlignment();
+ case Instruction::ICmp:
+ case Instruction::FCmp: {
+ // Widen compares. Generate vector compares.
+ bool FCmp = (it->getOpcode() == Instruction::FCmp);
+ CmpInst *Cmp = dyn_cast<CmpInst>(it);
+ Value *A = getVectorValue(it->getOperand(0));
+ Value *B = getVectorValue(it->getOperand(1));
+ if (FCmp)
+ WidenMap[it] = Builder.CreateFCmp(Cmp->getPredicate(), A, B);
+ else
+ WidenMap[it] = Builder.CreateICmp(Cmp->getPredicate(), A, B);
+ break;
+ }
- assert(!Legal->isUniform(Ptr) &&
- "We do not allow storing to uniform addresses");
+ case Instruction::Store: {
+ // Attempt to issue a wide store.
+ StoreInst *SI = dyn_cast<StoreInst>(it);
+ Type *StTy = VectorType::get(SI->getValueOperand()->getType(), VF);
+ Value *Ptr = SI->getPointerOperand();
+ unsigned Alignment = SI->getAlignment();
- GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
+ assert(!Legal->isUniform(Ptr) &&
+ "We do not allow storing to uniform addresses");
- // This store does not use GEPs.
- if (!Legal->isConsecutivePtr(Ptr)) {
- scalarizeInstruction(it);
- break;
- }
+ GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
- if (Gep) {
- // The last index does not have to be the induction. It can be
- // consecutive and be a function of the index. For example A[I+1];
- unsigned NumOperands = Gep->getNumOperands();
- Value *LastIndex = getVectorValue(Gep->getOperand(NumOperands - 1));
- LastIndex = Builder.CreateExtractElement(LastIndex, Zero);
-
- // Create the new GEP with the new induction variable.
- GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
- Gep2->setOperand(NumOperands - 1, LastIndex);
- Ptr = Builder.Insert(Gep2);
- } else {
- // Use the induction element ptr.
- assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
- Ptr = Builder.CreateExtractElement(getVectorValue(Ptr), Zero);
- }
- Ptr = Builder.CreateBitCast(Ptr, StTy->getPointerTo());
- Value *Val = getVectorValue(SI->getValueOperand());
- Builder.CreateStore(Val, Ptr)->setAlignment(Alignment);
+ // This store does not use GEPs.
+ if (!Legal->isConsecutivePtr(Ptr)) {
+ scalarizeInstruction(it);
break;
}
- case Instruction::Load: {
- // Attempt to issue a wide load.
- LoadInst *LI = dyn_cast<LoadInst>(it);
- Type *RetTy = VectorType::get(LI->getType(), VF);
- Value *Ptr = LI->getPointerOperand();
- unsigned Alignment = LI->getAlignment();
- GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
-
- // If the pointer is loop invariant or if it is non consecutive,
- // scalarize the load.
- bool Con = Legal->isConsecutivePtr(Ptr);
- if (Legal->isUniform(Ptr) || !Con) {
- scalarizeInstruction(it);
- break;
- }
- if (Gep) {
- // The last index does not have to be the induction. It can be
- // consecutive and be a function of the index. For example A[I+1];
- unsigned NumOperands = Gep->getNumOperands();
- Value *LastIndex = getVectorValue(Gep->getOperand(NumOperands -1));
- LastIndex = Builder.CreateExtractElement(LastIndex, Zero);
-
- // Create the new GEP with the new induction variable.
- GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
- Gep2->setOperand(NumOperands - 1, LastIndex);
- Ptr = Builder.Insert(Gep2);
- } else {
- // Use the induction element ptr.
- assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
- Ptr = Builder.CreateExtractElement(getVectorValue(Ptr), Zero);
- }
-
- Ptr = Builder.CreateBitCast(Ptr, RetTy->getPointerTo());
- LI = Builder.CreateLoad(Ptr);
- LI->setAlignment(Alignment);
- // Use this vector value for all users of the load.
- WidenMap[it] = LI;
- break;
+ if (Gep) {
+ // The last index does not have to be the induction. It can be
+ // consecutive and be a function of the index. For example A[I+1];
+ unsigned NumOperands = Gep->getNumOperands();
+ Value *LastIndex = getVectorValue(Gep->getOperand(NumOperands - 1));
+ LastIndex = Builder.CreateExtractElement(LastIndex, Zero);
+
+ // Create the new GEP with the new induction variable.
+ GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
+ Gep2->setOperand(NumOperands - 1, LastIndex);
+ Ptr = Builder.Insert(Gep2);
+ } else {
+ // Use the induction element ptr.
+ assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
+ Ptr = Builder.CreateExtractElement(getVectorValue(Ptr), Zero);
}
- case Instruction::ZExt:
- case Instruction::SExt:
- case Instruction::FPToUI:
- case Instruction::FPToSI:
- case Instruction::FPExt:
- case Instruction::PtrToInt:
- case Instruction::IntToPtr:
- case Instruction::SIToFP:
- case Instruction::UIToFP:
- case Instruction::Trunc:
- case Instruction::FPTrunc:
- case Instruction::BitCast: {
- /// Vectorize bitcasts.
- CastInst *CI = dyn_cast<CastInst>(it);
- Value *A = getVectorValue(it->getOperand(0));
- Type *DestTy = VectorType::get(CI->getType()->getScalarType(), VF);
- WidenMap[it] = Builder.CreateCast(CI->getOpcode(), A, DestTy);
+ Ptr = Builder.CreateBitCast(Ptr, StTy->getPointerTo());
+ Value *Val = getVectorValue(SI->getValueOperand());
+ Builder.CreateStore(Val, Ptr)->setAlignment(Alignment);
+ break;
+ }
+ case Instruction::Load: {
+ // Attempt to issue a wide load.
+ LoadInst *LI = dyn_cast<LoadInst>(it);
+ Type *RetTy = VectorType::get(LI->getType(), VF);
+ Value *Ptr = LI->getPointerOperand();
+ unsigned Alignment = LI->getAlignment();
+ GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
+
+ // If the pointer is loop invariant or if it is non consecutive,
+ // scalarize the load.
+ bool Con = Legal->isConsecutivePtr(Ptr);
+ if (Legal->isUniform(Ptr) || !Con) {
+ scalarizeInstruction(it);
break;
}
-
- case Instruction::Call: {
- assert(isTriviallyVectorizableIntrinsic(it));
- Module *M = BB->getParent()->getParent();
- IntrinsicInst *II = cast<IntrinsicInst>(it);
- Intrinsic::ID ID = II->getIntrinsicID();
- SmallVector<Value*, 4> Args;
- for (unsigned i = 0, ie = II->getNumArgOperands(); i != ie; ++i)
- Args.push_back(getVectorValue(II->getArgOperand(i)));
- Type *Tys[] = { VectorType::get(II->getType()->getScalarType(), VF) };
- Function *F = Intrinsic::getDeclaration(M, ID, Tys);
- WidenMap[it] = Builder.CreateCall(F, Args);
- break;
+
+ if (Gep) {
+ // The last index does not have to be the induction. It can be
+ // consecutive and be a function of the index. For example A[I+1];
+ unsigned NumOperands = Gep->getNumOperands();
+ Value *LastIndex = getVectorValue(Gep->getOperand(NumOperands -1));
+ LastIndex = Builder.CreateExtractElement(LastIndex, Zero);
+
+ // Create the new GEP with the new induction variable.
+ GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
+ Gep2->setOperand(NumOperands - 1, LastIndex);
+ Ptr = Builder.Insert(Gep2);
+ } else {
+ // Use the induction element ptr.
+ assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
+ Ptr = Builder.CreateExtractElement(getVectorValue(Ptr), Zero);
}
- default:
- // All other instructions are unsupported. Scalarize them.
- scalarizeInstruction(it);
- break;
+ Ptr = Builder.CreateBitCast(Ptr, RetTy->getPointerTo());
+ LI = Builder.CreateLoad(Ptr);
+ LI->setAlignment(Alignment);
+ // Use this vector value for all users of the load.
+ WidenMap[it] = LI;
+ break;
+ }
+ case Instruction::ZExt:
+ case Instruction::SExt:
+ case Instruction::FPToUI:
+ case Instruction::FPToSI:
+ case Instruction::FPExt:
+ case Instruction::PtrToInt:
+ case Instruction::IntToPtr:
+ case Instruction::SIToFP:
+ case Instruction::UIToFP:
+ case Instruction::Trunc:
+ case Instruction::FPTrunc:
+ case Instruction::BitCast: {
+ /// Vectorize bitcasts.
+ CastInst *CI = dyn_cast<CastInst>(it);
+ Value *A = getVectorValue(it->getOperand(0));
+ Type *DestTy = VectorType::get(CI->getType()->getScalarType(), VF);
+ WidenMap[it] = Builder.CreateCast(CI->getOpcode(), A, DestTy);
+ break;
+ }
+
+ case Instruction::Call: {
+ assert(isTriviallyVectorizableIntrinsic(it));
+ Module *M = BB->getParent()->getParent();
+ IntrinsicInst *II = cast<IntrinsicInst>(it);
+ Intrinsic::ID ID = II->getIntrinsicID();
+ SmallVector<Value*, 4> Args;
+ for (unsigned i = 0, ie = II->getNumArgOperands(); i != ie; ++i)
+ Args.push_back(getVectorValue(II->getArgOperand(i)));
+ Type *Tys[] = { VectorType::get(II->getType()->getScalarType(), VF) };
+ Function *F = Intrinsic::getDeclaration(M, ID, Tys);
+ WidenMap[it] = Builder.CreateCall(F, Args);
+ break;
+ }
+
+ default:
+ // All other instructions are unsupported. Scalarize them.
+ scalarizeInstruction(it);
+ break;
}// end of switch.
}// end of for_each instr.
}
// Check if we see any stores. If there are no stores, then we don't
// care if the pointers are *restrict*.
if (!Stores.size()) {
- DEBUG(dbgs() << "LV: Found a read-only loop!\n");
- return true;
+ DEBUG(dbgs() << "LV: Found a read-only loop!\n");
+ return true;
}
// Holds the read and read-write *pointers* that we find.
// We found a reduction var if we have reached the original
// phi node and we only have a single instruction with out-of-loop
// users.
- if (FoundStartPHI && ExitInstruction) {
- // This instruction is allowed to have out-of-loop users.
- AllowedExit.insert(ExitInstruction);
+ if (FoundStartPHI && ExitInstruction) {
+ // This instruction is allowed to have out-of-loop users.
+ AllowedExit.insert(ExitInstruction);
- // Save the description of this reduction variable.
- ReductionDescriptor RD(RdxStart, ExitInstruction, Kind);
- Reductions[Phi] = RD;
- return true;
- }
+ // Save the description of this reduction variable.
+ ReductionDescriptor RD(RdxStart, ExitInstruction, Kind);
+ Reductions[Phi] = RD;
+ return true;
+ }
// If we've reached the start PHI but did not find an outside user then
// this is dead code. Abort.
bool
LoopVectorizationLegality::isReductionInstr(Instruction *I,
ReductionKind Kind) {
- switch (I->getOpcode()) {
- default:
- return false;
- case Instruction::PHI:
- // possibly.
- return true;
- case Instruction::Add:
- case Instruction::Sub:
- return Kind == IntegerAdd;
- case Instruction::Mul:
- return Kind == IntegerMult;
- case Instruction::And:
- return Kind == IntegerAnd;
- case Instruction::Or:
- return Kind == IntegerOr;
- case Instruction::Xor:
- return Kind == IntegerXor;
- }
+ switch (I->getOpcode()) {
+ default:
+ return false;
+ case Instruction::PHI:
+ // possibly.
+ return true;
+ case Instruction::Add:
+ case Instruction::Sub:
+ return Kind == IntegerAdd;
+ case Instruction::Mul:
+ return Kind == IntegerMult;
+ case Instruction::And:
+ return Kind == IntegerAnd;
+ case Instruction::Or:
+ return Kind == IntegerOr;
+ case Instruction::Xor:
+ return Kind == IntegerXor;
+ }
}
LoopVectorizationLegality::InductionKind
// The isntructions below can trap.
switch (it->getOpcode()) {
- default: continue;
- case Instruction::UDiv:
- case Instruction::SDiv:
- case Instruction::URem:
- case Instruction::SRem:
- return false;
+ default: continue;
+ case Instruction::UDiv:
+ case Instruction::SDiv:
+ case Instruction::URem:
+ case Instruction::SRem:
+ return false;
}
}
// TODO: We need to estimate the cost of intrinsic calls.
switch (I->getOpcode()) {
- case Instruction::GetElementPtr:
- // We mark this instruction as zero-cost because scalar GEPs are usually
- // lowered to the intruction addressing mode. At the moment we don't
- // generate vector geps.
- return 0;
- case Instruction::Br: {
- return VTTI->getCFInstrCost(I->getOpcode());
- }
- case Instruction::PHI:
- //TODO: IF-converted IFs become selects.
- return 0;
- case Instruction::Add:
- case Instruction::FAdd:
- case Instruction::Sub:
- case Instruction::FSub:
- case Instruction::Mul:
- case Instruction::FMul:
- case Instruction::UDiv:
- case Instruction::SDiv:
- case Instruction::FDiv:
- case Instruction::URem:
- case Instruction::SRem:
- case Instruction::FRem:
- case Instruction::Shl:
- case Instruction::LShr:
- case Instruction::AShr:
- case Instruction::And:
- case Instruction::Or:
- case Instruction::Xor:
- return VTTI->getArithmeticInstrCost(I->getOpcode(), VectorTy);
- case Instruction::Select: {
- SelectInst *SI = cast<SelectInst>(I);
- const SCEV *CondSCEV = SE->getSCEV(SI->getCondition());
- bool ScalarCond = (SE->isLoopInvariant(CondSCEV, TheLoop));
- Type *CondTy = SI->getCondition()->getType();
- if (ScalarCond)
- CondTy = VectorType::get(CondTy, VF);
-
- return VTTI->getCmpSelInstrCost(I->getOpcode(), VectorTy, CondTy);
- }
- case Instruction::ICmp:
- case Instruction::FCmp: {
- Type *ValTy = I->getOperand(0)->getType();
- VectorTy = ToVectorTy(ValTy, VF);
- return VTTI->getCmpSelInstrCost(I->getOpcode(), VectorTy);
- }
- case Instruction::Store: {
- StoreInst *SI = cast<StoreInst>(I);
- Type *ValTy = SI->getValueOperand()->getType();
- VectorTy = ToVectorTy(ValTy, VF);
-
- if (VF == 1)
- return VTTI->getMemoryOpCost(I->getOpcode(), ValTy,
- SI->getAlignment(), SI->getPointerAddressSpace());
-
- // Scalarized stores.
- if (!Legal->isConsecutivePtr(SI->getPointerOperand())) {
- unsigned Cost = 0;
- unsigned ExtCost = VTTI->getInstrCost(Instruction::ExtractElement,
- ValTy);
- // The cost of extracting from the value vector.
- Cost += VF * (ExtCost);
- // The cost of the scalar stores.
- Cost += VF * VTTI->getMemoryOpCost(I->getOpcode(),
- ValTy->getScalarType(),
- SI->getAlignment(),
- SI->getPointerAddressSpace());
- return Cost;
- }
-
- // Wide stores.
- return VTTI->getMemoryOpCost(I->getOpcode(), VectorTy, SI->getAlignment(),
+ case Instruction::GetElementPtr:
+ // We mark this instruction as zero-cost because scalar GEPs are usually
+ // lowered to the intruction addressing mode. At the moment we don't
+ // generate vector geps.
+ return 0;
+ case Instruction::Br: {
+ return VTTI->getCFInstrCost(I->getOpcode());
+ }
+ case Instruction::PHI:
+ //TODO: IF-converted IFs become selects.
+ return 0;
+ case Instruction::Add:
+ case Instruction::FAdd:
+ case Instruction::Sub:
+ case Instruction::FSub:
+ case Instruction::Mul:
+ case Instruction::FMul:
+ case Instruction::UDiv:
+ case Instruction::SDiv:
+ case Instruction::FDiv:
+ case Instruction::URem:
+ case Instruction::SRem:
+ case Instruction::FRem:
+ case Instruction::Shl:
+ case Instruction::LShr:
+ case Instruction::AShr:
+ case Instruction::And:
+ case Instruction::Or:
+ case Instruction::Xor:
+ return VTTI->getArithmeticInstrCost(I->getOpcode(), VectorTy);
+ case Instruction::Select: {
+ SelectInst *SI = cast<SelectInst>(I);
+ const SCEV *CondSCEV = SE->getSCEV(SI->getCondition());
+ bool ScalarCond = (SE->isLoopInvariant(CondSCEV, TheLoop));
+ Type *CondTy = SI->getCondition()->getType();
+ if (ScalarCond)
+ CondTy = VectorType::get(CondTy, VF);
+
+ return VTTI->getCmpSelInstrCost(I->getOpcode(), VectorTy, CondTy);
+ }
+ case Instruction::ICmp:
+ case Instruction::FCmp: {
+ Type *ValTy = I->getOperand(0)->getType();
+ VectorTy = ToVectorTy(ValTy, VF);
+ return VTTI->getCmpSelInstrCost(I->getOpcode(), VectorTy);
+ }
+ case Instruction::Store: {
+ StoreInst *SI = cast<StoreInst>(I);
+ Type *ValTy = SI->getValueOperand()->getType();
+ VectorTy = ToVectorTy(ValTy, VF);
+
+ if (VF == 1)
+ return VTTI->getMemoryOpCost(I->getOpcode(), ValTy,
+ SI->getAlignment(),
SI->getPointerAddressSpace());
+
+ // Scalarized stores.
+ if (!Legal->isConsecutivePtr(SI->getPointerOperand())) {
+ unsigned Cost = 0;
+ unsigned ExtCost = VTTI->getInstrCost(Instruction::ExtractElement,
+ ValTy);
+ // The cost of extracting from the value vector.
+ Cost += VF * (ExtCost);
+ // The cost of the scalar stores.
+ Cost += VF * VTTI->getMemoryOpCost(I->getOpcode(),
+ ValTy->getScalarType(),
+ SI->getAlignment(),
+ SI->getPointerAddressSpace());
+ return Cost;
}
- case Instruction::Load: {
- LoadInst *LI = cast<LoadInst>(I);
-
- if (VF == 1)
- return VTTI->getMemoryOpCost(I->getOpcode(), RetTy,
- LI->getAlignment(),
- LI->getPointerAddressSpace());
-
- // Scalarized loads.
- if (!Legal->isConsecutivePtr(LI->getPointerOperand())) {
- unsigned Cost = 0;
- unsigned InCost = VTTI->getInstrCost(Instruction::InsertElement, RetTy);
- // The cost of inserting the loaded value into the result vector.
- Cost += VF * (InCost);
- // The cost of the scalar stores.
- Cost += VF * VTTI->getMemoryOpCost(I->getOpcode(),
- RetTy->getScalarType(),
- LI->getAlignment(),
- LI->getPointerAddressSpace());
- return Cost;
- }
- // Wide loads.
- return VTTI->getMemoryOpCost(I->getOpcode(), VectorTy, LI->getAlignment(),
+ // Wide stores.
+ return VTTI->getMemoryOpCost(I->getOpcode(), VectorTy, SI->getAlignment(),
+ SI->getPointerAddressSpace());
+ }
+ case Instruction::Load: {
+ LoadInst *LI = cast<LoadInst>(I);
+
+ if (VF == 1)
+ return VTTI->getMemoryOpCost(I->getOpcode(), RetTy,
+ LI->getAlignment(),
LI->getPointerAddressSpace());
- }
- case Instruction::ZExt:
- case Instruction::SExt:
- case Instruction::FPToUI:
- case Instruction::FPToSI:
- case Instruction::FPExt:
- case Instruction::PtrToInt:
- case Instruction::IntToPtr:
- case Instruction::SIToFP:
- case Instruction::UIToFP:
- case Instruction::Trunc:
- case Instruction::FPTrunc:
- case Instruction::BitCast: {
- Type *SrcVecTy = ToVectorTy(I->getOperand(0)->getType(), VF);
- return VTTI->getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy);
- }
- case Instruction::Call: {
- assert(isTriviallyVectorizableIntrinsic(I));
- IntrinsicInst *II = cast<IntrinsicInst>(I);
- Type *RetTy = ToVectorTy(II->getType(), VF);
- SmallVector<Type*, 4> Tys;
- for (unsigned i = 0, ie = II->getNumArgOperands(); i != ie; ++i)
- Tys.push_back(ToVectorTy(II->getArgOperand(i)->getType(), VF));
- return VTTI->getIntrinsicInstrCost(II->getIntrinsicID(), RetTy, Tys);
- }
- default: {
- // We are scalarizing the instruction. Return the cost of the scalar
- // instruction, plus the cost of insert and extract into vector
- // elements, times the vector width.
+
+ // Scalarized loads.
+ if (!Legal->isConsecutivePtr(LI->getPointerOperand())) {
unsigned Cost = 0;
+ unsigned InCost = VTTI->getInstrCost(Instruction::InsertElement, RetTy);
+ // The cost of inserting the loaded value into the result vector.
+ Cost += VF * (InCost);
+ // The cost of the scalar stores.
+ Cost += VF * VTTI->getMemoryOpCost(I->getOpcode(),
+ RetTy->getScalarType(),
+ LI->getAlignment(),
+ LI->getPointerAddressSpace());
+ return Cost;
+ }
- bool IsVoid = RetTy->isVoidTy();
+ // Wide loads.
+ return VTTI->getMemoryOpCost(I->getOpcode(), VectorTy, LI->getAlignment(),
+ LI->getPointerAddressSpace());
+ }
+ case Instruction::ZExt:
+ case Instruction::SExt:
+ case Instruction::FPToUI:
+ case Instruction::FPToSI:
+ case Instruction::FPExt:
+ case Instruction::PtrToInt:
+ case Instruction::IntToPtr:
+ case Instruction::SIToFP:
+ case Instruction::UIToFP:
+ case Instruction::Trunc:
+ case Instruction::FPTrunc:
+ case Instruction::BitCast: {
+ Type *SrcVecTy = ToVectorTy(I->getOperand(0)->getType(), VF);
+ return VTTI->getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy);
+ }
+ case Instruction::Call: {
+ assert(isTriviallyVectorizableIntrinsic(I));
+ IntrinsicInst *II = cast<IntrinsicInst>(I);
+ Type *RetTy = ToVectorTy(II->getType(), VF);
+ SmallVector<Type*, 4> Tys;
+ for (unsigned i = 0, ie = II->getNumArgOperands(); i != ie; ++i)
+ Tys.push_back(ToVectorTy(II->getArgOperand(i)->getType(), VF));
+ return VTTI->getIntrinsicInstrCost(II->getIntrinsicID(), RetTy, Tys);
+ }
+ default: {
+ // We are scalarizing the instruction. Return the cost of the scalar
+ // instruction, plus the cost of insert and extract into vector
+ // elements, times the vector width.
+ unsigned Cost = 0;
- unsigned InsCost = (IsVoid ? 0 :
- VTTI->getInstrCost(Instruction::InsertElement,
- VectorTy));
+ bool IsVoid = RetTy->isVoidTy();
- unsigned ExtCost = VTTI->getInstrCost(Instruction::ExtractElement,
- VectorTy);
+ unsigned InsCost = (IsVoid ? 0 :
+ VTTI->getInstrCost(Instruction::InsertElement,
+ VectorTy));
- // The cost of inserting the results plus extracting each one of the
- // operands.
- Cost += VF * (InsCost + ExtCost * I->getNumOperands());
+ unsigned ExtCost = VTTI->getInstrCost(Instruction::ExtractElement,
+ VectorTy);
- // The cost of executing VF copies of the scalar instruction.
- Cost += VF * VTTI->getInstrCost(I->getOpcode(), RetTy);
- return Cost;
- }
+ // The cost of inserting the results plus extracting each one of the
+ // operands.
+ Cost += VF * (InsCost + ExtCost * I->getNumOperands());
+
+ // The cost of executing VF copies of the scalar instruction.
+ Cost += VF * VTTI->getInstrCost(I->getOpcode(), RetTy);
+ return Cost;
+ }
}// end of switch.
}
return VectorType::get(Scalar, VF);
}
-} // namespace
-
char LoopVectorize::ID = 0;
static const char lv_name[] = "Loop Vectorization";
INITIALIZE_PASS_BEGIN(LoopVectorize, LV_NAME, lv_name, false, false)
return new LoopVectorize();
}
}
+
+
--- /dev/null
+//===- LoopVectorize.h --- A Loop Vectorizer ------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is the LLVM loop vectorizer. This pass modifies 'vectorizable' loops
+// and generates target-independent LLVM-IR. Legalization of the IR is done
+// in the codegen. However, the vectorizes uses (will use) the codegen
+// interfaces to generate IR that is likely to result in an optimal binary.
+//
+// The loop vectorizer combines consecutive loop iteration into a single
+// 'wide' iteration. After this transformation the index is incremented
+// by the SIMD vector width, and not by one.
+//
+// This pass has three parts:
+// 1. The main loop pass that drives the different parts.
+// 2. LoopVectorizationLegality - A unit that checks for the legality
+// of the vectorization.
+// 3. InnerLoopVectorizer - A unit that performs the actual
+// widening of instructions.
+// 4. LoopVectorizationCostModel - A unit that checks for the profitability
+// of vectorization. It decides on the optimal vector width, which
+// can be one, if vectorization is not profitable.
+//
+//===----------------------------------------------------------------------===//
+//
+// The reduction-variable vectorization is based on the paper:
+// D. Nuzman and R. Henderson. Multi-platform Auto-vectorization.
+//
+// Variable uniformity checks are inspired by:
+// Karrenberg, R. and Hack, S. Whole Function Vectorization.
+//
+// Other ideas/concepts are from:
+// A. Zaks and D. Nuzman. Autovectorization in GCC-two years later.
+//
+// S. Maleki, Y. Gao, M. Garzaran, T. Wong and D. Padua. An Evaluation of
+// Vectorizing Compilers.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_TRANSFORM_VECTORIZE_LOOP_VECTORIZE_H
+#define LLVM_TRANSFORM_VECTORIZE_LOOP_VECTORIZE_H
+
+#define LV_NAME "loop-vectorize"
+#define DEBUG_TYPE LV_NAME
+
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/IRBuilder.h"
+
+#include <algorithm>
+using namespace llvm;
+
+/// We don't vectorize loops with a known constant trip count below this number.
+const unsigned TinyTripCountThreshold = 16;
+
+/// When performing a runtime memory check, do not check more than this
+/// number of pointers. Notice that the check is quadratic!
+const unsigned RuntimeMemoryCheckThreshold = 4;
+
+/// This is the highest vector width that we try to generate.
+const unsigned MaxVectorSize = 8;
+
+namespace llvm {
+
+// Forward declarations.
+class LoopVectorizationLegality;
+class LoopVectorizationCostModel;
+class VectorTargetTransformInfo;
+
+/// InnerLoopVectorizer vectorizes loops which contain only one basic
+/// block to a specified vectorization factor (VF).
+/// This class performs the widening of scalars into vectors, or multiple
+/// scalars. This class also implements the following features:
+/// * It inserts an epilogue loop for handling loops that don't have iteration
+/// counts that are known to be a multiple of the vectorization factor.
+/// * It handles the code generation for reduction variables.
+/// * Scalarization (implementation using scalars) of un-vectorizable
+/// instructions.
+/// InnerLoopVectorizer does not perform any vectorization-legality
+/// checks, and relies on the caller to check for the different legality
+/// aspects. The InnerLoopVectorizer relies on the
+/// LoopVectorizationLegality class to provide information about the induction
+/// and reduction variables that were found to a given vectorization factor.
+class InnerLoopVectorizer {
+public:
+ /// Ctor.
+ InnerLoopVectorizer(Loop *Orig, ScalarEvolution *Se, LoopInfo *Li,
+ DominatorTree *Dt, DataLayout *Dl, unsigned VecWidth):
+ OrigLoop(Orig), SE(Se), LI(Li), DT(Dt), DL(Dl), VF(VecWidth),
+ Builder(Se->getContext()), Induction(0), OldInduction(0) { }
+
+ // Perform the actual loop widening (vectorization).
+ void vectorize(LoopVectorizationLegality *Legal) {
+ // Create a new empty loop. Unlink the old loop and connect the new one.
+ createEmptyLoop(Legal);
+ // Widen each instruction in the old loop to a new one in the new loop.
+ // Use the Legality module to find the induction and reduction variables.
+ vectorizeLoop(Legal);
+ // Register the new loop and update the analysis passes.
+ updateAnalysis();
+ }
+
+private:
+ /// A small list of PHINodes.
+ typedef SmallVector<PHINode*, 4> PhiVector;
+
+ /// Add code that checks at runtime if the accessed arrays overlap.
+ /// Returns the comparator value or NULL if no check is needed.
+ Value *addRuntimeCheck(LoopVectorizationLegality *Legal,
+ Instruction *Loc);
+ /// Create an empty loop, based on the loop ranges of the old loop.
+ void createEmptyLoop(LoopVectorizationLegality *Legal);
+ /// Copy and widen the instructions from the old loop.
+ void vectorizeLoop(LoopVectorizationLegality *Legal);
+
+ /// A helper function that computes the predicate of the block BB, assuming
+ /// that the header block of the loop is set to True. It returns the *entry*
+ /// mask for the block BB.
+ Value *createBlockInMask(BasicBlock *BB);
+ /// A helper function that computes the predicate of the edge between SRC
+ /// and DST.
+ Value *createEdgeMask(BasicBlock *Src, BasicBlock *Dst);
+
+ /// A helper function to vectorize a single BB within the innermost loop.
+ void vectorizeBlockInLoop(LoopVectorizationLegality *Legal, BasicBlock *BB,
+ PhiVector *PV);
+
+ /// Insert the new loop to the loop hierarchy and pass manager
+ /// and update the analysis passes.
+ void updateAnalysis();
+
+ /// This instruction is un-vectorizable. Implement it as a sequence
+ /// of scalars.
+ void scalarizeInstruction(Instruction *Instr);
+
+ /// Create a broadcast instruction. This method generates a broadcast
+ /// instruction (shuffle) for loop invariant values and for the induction
+ /// value. If this is the induction variable then we extend it to N, N+1, ...
+ /// this is needed because each iteration in the loop corresponds to a SIMD
+ /// element.
+ Value *getBroadcastInstrs(Value *V);
+
+ /// This function adds 0, 1, 2 ... to each vector element, starting at zero.
+ /// If Negate is set then negative numbers are added e.g. (0, -1, -2, ...).
+ Value *getConsecutiveVector(Value* Val, bool Negate = false);
+
+ /// When we go over instructions in the basic block we rely on previous
+ /// values within the current basic block or on loop invariant values.
+ /// When we widen (vectorize) values we place them in the map. If the values
+ /// are not within the map, they have to be loop invariant, so we simply
+ /// broadcast them into a vector.
+ Value *getVectorValue(Value *V);
+
+ /// Get a uniform vector of constant integers. We use this to get
+ /// vectors of ones and zeros for the reduction code.
+ Constant* getUniformVector(unsigned Val, Type* ScalarTy);
+
+ typedef DenseMap<Value*, Value*> ValueMap;
+
+ /// The original loop.
+ Loop *OrigLoop;
+ // Scev analysis to use.
+ ScalarEvolution *SE;
+ // Loop Info.
+ LoopInfo *LI;
+ // Dominator Tree.
+ DominatorTree *DT;
+ // Data Layout.
+ DataLayout *DL;
+ // The vectorization factor to use.
+ unsigned VF;
+
+ // The builder that we use
+ IRBuilder<> Builder;
+
+ // --- Vectorization state ---
+
+ /// The vector-loop preheader.
+ BasicBlock *LoopVectorPreHeader;
+ /// The scalar-loop preheader.
+ BasicBlock *LoopScalarPreHeader;
+ /// Middle Block between the vector and the scalar.
+ BasicBlock *LoopMiddleBlock;
+ ///The ExitBlock of the scalar loop.
+ BasicBlock *LoopExitBlock;
+ ///The vector loop body.
+ BasicBlock *LoopVectorBody;
+ ///The scalar loop body.
+ BasicBlock *LoopScalarBody;
+ ///The first bypass block.
+ BasicBlock *LoopBypassBlock;
+
+ /// The new Induction variable which was added to the new block.
+ PHINode *Induction;
+ /// The induction variable of the old basic block.
+ PHINode *OldInduction;
+ // Maps scalars to widened vectors.
+ ValueMap WidenMap;
+};
+
+/// LoopVectorizationLegality checks if it is legal to vectorize a loop, and
+/// to what vectorization factor.
+/// This class does not look at the profitability of vectorization, only the
+/// legality. This class has two main kinds of checks:
+/// * Memory checks - The code in canVectorizeMemory checks if vectorization
+/// will change the order of memory accesses in a way that will change the
+/// correctness of the program.
+/// * Scalars checks - The code in canVectorizeInstrs and canVectorizeMemory
+/// checks for a number of different conditions, such as the availability of a
+/// single induction variable, that all types are supported and vectorize-able,
+/// etc. This code reflects the capabilities of InnerLoopVectorizer.
+/// This class is also used by InnerLoopVectorizer for identifying
+/// induction variable and the different reduction variables.
+class LoopVectorizationLegality {
+public:
+ LoopVectorizationLegality(Loop *Lp, ScalarEvolution *Se, DataLayout *Dl,
+ DominatorTree *Dt):
+ TheLoop(Lp), SE(Se), DL(Dl), DT(Dt), Induction(0) { }
+
+ /// This enum represents the kinds of reductions that we support.
+ enum ReductionKind {
+ NoReduction, /// Not a reduction.
+ IntegerAdd, /// Sum of numbers.
+ IntegerMult, /// Product of numbers.
+ IntegerOr, /// Bitwise or logical OR of numbers.
+ IntegerAnd, /// Bitwise or logical AND of numbers.
+ IntegerXor /// Bitwise or logical XOR of numbers.
+ };
+
+ /// This enum represents the kinds of inductions that we support.
+ enum InductionKind {
+ NoInduction, /// Not an induction variable.
+ IntInduction, /// Integer induction variable. Step = 1.
+ ReverseIntInduction, /// Reverse int induction variable. Step = -1.
+ PtrInduction /// Pointer induction variable. Step = sizeof(elem).
+ };
+
+ /// This POD struct holds information about reduction variables.
+ struct ReductionDescriptor {
+ // Default C'tor
+ ReductionDescriptor():
+ StartValue(0), LoopExitInstr(0), Kind(NoReduction) {}
+
+ // C'tor.
+ ReductionDescriptor(Value *Start, Instruction *Exit, ReductionKind K):
+ StartValue(Start), LoopExitInstr(Exit), Kind(K) {}
+
+ // The starting value of the reduction.
+ // It does not have to be zero!
+ Value *StartValue;
+ // The instruction who's value is used outside the loop.
+ Instruction *LoopExitInstr;
+ // The kind of the reduction.
+ ReductionKind Kind;
+ };
+
+ // This POD struct holds information about the memory runtime legality
+ // check that a group of pointers do not overlap.
+ struct RuntimePointerCheck {
+ RuntimePointerCheck(): Need(false) {}
+
+ /// Reset the state of the pointer runtime information.
+ void reset() {
+ Need = false;
+ Pointers.clear();
+ Starts.clear();
+ Ends.clear();
+ }
+
+ /// Insert a pointer and calculate the start and end SCEVs.
+ void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr);
+
+ /// This flag indicates if we need to add the runtime check.
+ bool Need;
+ /// Holds the pointers that we need to check.
+ SmallVector<Value*, 2> Pointers;
+ /// Holds the pointer value at the beginning of the loop.
+ SmallVector<const SCEV*, 2> Starts;
+ /// Holds the pointer value at the end of the loop.
+ SmallVector<const SCEV*, 2> Ends;
+ };
+
+ /// A POD for saving information about induction variables.
+ struct InductionInfo {
+ /// Ctors.
+ InductionInfo(Value *Start, InductionKind K):
+ StartValue(Start), IK(K) {};
+ InductionInfo(): StartValue(0), IK(NoInduction) {};
+ /// Start value.
+ Value *StartValue;
+ /// Induction kind.
+ InductionKind IK;
+ };
+
+ /// ReductionList contains the reduction descriptors for all
+ /// of the reductions that were found in the loop.
+ typedef DenseMap<PHINode*, ReductionDescriptor> ReductionList;
+
+ /// InductionList saves induction variables and maps them to the
+ /// induction descriptor.
+ typedef DenseMap<PHINode*, InductionInfo> InductionList;
+
+ /// Returns true if it is legal to vectorize this loop.
+ /// This does not mean that it is profitable to vectorize this
+ /// loop, only that it is legal to do so.
+ bool canVectorize();
+
+ /// Returns the Induction variable.
+ PHINode *getInduction() {return Induction;}
+
+ /// Returns the reduction variables found in the loop.
+ ReductionList *getReductionVars() { return &Reductions; }
+
+ /// Returns the induction variables found in the loop.
+ InductionList *getInductionVars() { return &Inductions; }
+
+ /// Return true if the block BB needs to be predicated in order for the loop
+ /// to be vectorized.
+ bool blockNeedsPredication(BasicBlock *BB);
+
+ /// Check if this pointer is consecutive when vectorizing. This happens
+ /// when the last index of the GEP is the induction variable, or that the
+ /// pointer itself is an induction variable.
+ /// This check allows us to vectorize A[idx] into a wide load/store.
+ bool isConsecutivePtr(Value *Ptr);
+
+ /// Returns true if the value V is uniform within the loop.
+ bool isUniform(Value *V);
+
+ /// Returns true if this instruction will remain scalar after vectorization.
+ bool isUniformAfterVectorization(Instruction* I) {return Uniforms.count(I);}
+
+ /// Returns the information that we collected about runtime memory check.
+ RuntimePointerCheck *getRuntimePointerCheck() {return &PtrRtCheck; }
+private:
+ /// Check if a single basic block loop is vectorizable.
+ /// At this point we know that this is a loop with a constant trip count
+ /// and we only need to check individual instructions.
+ bool canVectorizeInstrs();
+
+ /// When we vectorize loops we may change the order in which
+ /// we read and write from memory. This method checks if it is
+ /// legal to vectorize the code, considering only memory constrains.
+ /// Returns true if the loop is vectorizable
+ bool canVectorizeMemory();
+
+ /// Return true if we can vectorize this loop using the IF-conversion
+ /// transformation.
+ bool canVectorizeWithIfConvert();
+
+ /// Collect the variables that need to stay uniform after vectorization.
+ void collectLoopUniforms();
+
+ /// Return true if all of the instructions in the block can be speculatively
+ /// executed.
+ bool blockCanBePredicated(BasicBlock *BB);
+
+ /// Returns True, if 'Phi' is the kind of reduction variable for type
+ /// 'Kind'. If this is a reduction variable, it adds it to ReductionList.
+ bool AddReductionVar(PHINode *Phi, ReductionKind Kind);
+ /// Returns true if the instruction I can be a reduction variable of type
+ /// 'Kind'.
+ bool isReductionInstr(Instruction *I, ReductionKind Kind);
+ /// Returns the induction kind of Phi. This function may return NoInduction
+ /// if the PHI is not an induction variable.
+ InductionKind isInductionVariable(PHINode *Phi);
+ /// Return true if can compute the address bounds of Ptr within the loop.
+ bool hasComputableBounds(Value *Ptr);
+
+ /// The loop that we evaluate.
+ Loop *TheLoop;
+ /// Scev analysis.
+ ScalarEvolution *SE;
+ /// DataLayout analysis.
+ DataLayout *DL;
+ // Dominators.
+ DominatorTree *DT;
+
+ // --- vectorization state --- //
+
+ /// Holds the integer induction variable. This is the counter of the
+ /// loop.
+ PHINode *Induction;
+ /// Holds the reduction variables.
+ ReductionList Reductions;
+ /// Holds all of the induction variables that we found in the loop.
+ /// Notice that inductions don't need to start at zero and that induction
+ /// variables can be pointers.
+ InductionList Inductions;
+
+ /// Allowed outside users. This holds the reduction
+ /// vars which can be accessed from outside the loop.
+ SmallPtrSet<Value*, 4> AllowedExit;
+ /// This set holds the variables which are known to be uniform after
+ /// vectorization.
+ SmallPtrSet<Instruction*, 4> Uniforms;
+ /// We need to check that all of the pointers in this list are disjoint
+ /// at runtime.
+ RuntimePointerCheck PtrRtCheck;
+};
+
+/// LoopVectorizationCostModel - estimates the expected speedups due to
+/// vectorization.
+/// In many cases vectorization is not profitable. This can happen because
+/// of a number of reasons. In this class we mainly attempt to predict
+/// the expected speedup/slowdowns due to the supported instruction set.
+/// We use the VectorTargetTransformInfo to query the different backends
+/// for the cost of different operations.
+class LoopVectorizationCostModel {
+public:
+ /// C'tor.
+ LoopVectorizationCostModel(Loop *Lp, ScalarEvolution *Se,
+ LoopVectorizationLegality *Leg,
+ const VectorTargetTransformInfo *Vtti):
+ TheLoop(Lp), SE(Se), Legal(Leg), VTTI(Vtti) { }
+
+ /// Returns the most profitable vectorization factor for the loop that is
+ /// smaller or equal to the VF argument. This method checks every power
+ /// of two up to VF.
+ unsigned findBestVectorizationFactor(unsigned VF = MaxVectorSize);
+
+private:
+ /// Returns the expected execution cost. The unit of the cost does
+ /// not matter because we use the 'cost' units to compare different
+ /// vector widths. The cost that is returned is *not* normalized by
+ /// the factor width.
+ unsigned expectedCost(unsigned VF);
+
+ /// Returns the execution time cost of an instruction for a given vector
+ /// width. Vector width of one means scalar.
+ unsigned getInstructionCost(Instruction *I, unsigned VF);
+
+ /// A helper function for converting Scalar types to vector types.
+ /// If the incoming type is void, we return void. If the VF is 1, we return
+ /// the scalar type.
+ static Type* ToVectorTy(Type *Scalar, unsigned VF);
+
+ /// The loop that we evaluate.
+ Loop *TheLoop;
+ /// Scev analysis.
+ ScalarEvolution *SE;
+
+ /// Vectorization legality.
+ LoopVectorizationLegality *Legal;
+ /// Vector target information.
+ const VectorTargetTransformInfo *VTTI;
+};
+
+}// namespace llvm
+
+#endif //LLVM_TRANSFORM_VECTORIZE_LOOP_VECTORIZE_H
+
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