JIT: rework gtCanOptimizeTypeEquality (dotnet/coreclr#13657)

Instead of looking at the verifier type for a local (which is currently never
set for ref classes in CoreCLR), use the new utilties for finding ref type
class handles.

Since the utility works on all tree types, also remove the restriction that
the tree must be a local.

Closes dotnet/coreclr#13555.

Commit migrated from https://github.com/dotnet/coreclr/commit/a89ed32bd6f7bd7424336725427f335f2b5edcfd

diff --git a/src/coreclr/src/jit/gentree.cpp b/src/coreclr/src/jit/gentree.cpp
index dd3d5bd..2284197 100644 (file)
--- a/src/coreclr/src/jit/gentree.cpp
+++ b/src/coreclr/src/jit/gentree.cpp
@@ -14743,11 +14743,26 @@ void Compiler::gtCheckQuirkAddrExposedLclVar(GenTreePtr tree, GenTreeStack* pare
 #endif
 }
 
-// Checks to see if we're allowed to optimize Type::op_Equality or Type::op_Inequality on this operand.
-// We're allowed to convert to GT_EQ/GT_NE if one of the operands is:
-//  1) The result of Object::GetType
-//  2) The result of typeof(...)
-//  3) a local variable of type RuntimeType.
+//------------------------------------------------------------------------
+// gtCanOptimizeTypeEquality: check if tree is a suitable input for a type
+//    equality optimization
+//
+// Arguments:
+//    tree - tree to examine
+//
+// Return Value:
+//    True, if value of tree can be used to optimize type equality tests
+//
+// Notes:
+//    Checks to see if the jit is able to optimize Type::op_Equality or
+//    Type::op_Inequality calls that consume this tree.
+//
+//    The jit can safely convert these methods to GT_EQ/GT_NE if one of
+//    the operands is:
+//    1) The result of Object::GetType
+//    2) The result of typeof(...)
+//    3) Is otherwise known to have type RuntimeType
+
 bool Compiler::gtCanOptimizeTypeEquality(GenTreePtr tree)
 {
     if (tree->gtOper == GT_CALL)
@@ -14771,15 +14786,15 @@ bool Compiler::gtCanOptimizeTypeEquality(GenTreePtr tree)
     {
         return true;
     }
-    else if (tree->gtOper == GT_LCL_VAR)
+    else
     {
-        LclVarDsc* lcl = &(lvaTable[tree->gtLclVarCommon.gtLclNum]);
-        if (lcl->TypeGet() == TYP_REF)
+        bool                 isExact   = false;
+        bool                 isNonNull = false;
+        CORINFO_CLASS_HANDLE clsHnd    = gtGetClassHandle(tree, &isExact, &isNonNull);
+
+        if (clsHnd == info.compCompHnd->getBuiltinClass(CLASSID_RUNTIME_TYPE))
         {
-            if (lcl->lvVerTypeInfo.GetClassHandle() == info.compCompHnd->getBuiltinClass(CLASSID_RUNTIME_TYPE))
-            {
-                return true;
-            }
+            return true;
         }
     }
     return false;