Two fixes:

1. Fix a REALLY nasty cyclic replacement issue that Anshu discovered, causing
   nondeterminstic crashes and memory corruption.
2. For performance, don't go inserting constantexpr casts of GV pointers.

This should definitely go into 1.3

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15568 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/ExprTypeConvert.cpp b/lib/Transforms/ExprTypeConvert.cpp
index 0f80c2f..a657f02 100644 (file)
--- a/lib/Transforms/ExprTypeConvert.cpp
+++ b/lib/Transforms/ExprTypeConvert.cpp
@@ -151,7 +151,7 @@ bool llvm::ExpressionConvertibleToType(Value *V, const Type *Ty,
   // If it's a constant... all constants can be converted to a different
   // type.
   //
-  if (Constant *CPV = dyn_cast<Constant>(V))
+  if (isa<Constant>(V) && !isa<GlobalValue>(V))
     return true;
   
   CTMap[V] = Ty;
@@ -984,10 +984,9 @@ static void ConvertOperandToType(User *U, Value *OldVal, Value *NewVal,
 
     unsigned OtherIdx = (OldVal == I->getOperand(0)) ? 1 : 0;
     Value *OtherOp    = I->getOperand(OtherIdx);
+    Res->setOperand(!OtherIdx, NewVal);
     Value *NewOther   = ConvertExpressionToType(OtherOp, NewTy, VMC, TD);
-
     Res->setOperand(OtherIdx, NewOther);
-    Res->setOperand(!OtherIdx, NewVal);
     break;
   }
   case Instruction::Shl: