Respect address space sizes in isEliminableCastPair.

This avoids constant folding bitcast/ptrtoint/inttoptr combinations
that have illegal bitcasts between differently sized address spaces.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187455 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 4 deletions

diff --git a/lib/IR/ConstantFold.cpp b/lib/IR/ConstantFold.cpp
index da9762fa62..8c5a983701 100644
--- a/lib/IR/ConstantFold.cpp
+++ b/lib/IR/ConstantFold.cpp
@@ -75,7 +75,7 @@ static unsigned
 foldConstantCastPair(
   unsigned opc,          ///< opcode of the second cast constant expression
   ConstantExpr *Op,      ///< the first cast constant expression
-  Type *DstTy      ///< desintation type of the first cast
+  Type *DstTy            ///< destination type of the first cast
 ) {
   assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
   assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
@@ -87,13 +87,14 @@ foldConstantCastPair(
   Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode());
   Instruction::CastOps secondOp = Instruction::CastOps(opc);
 
-  // Assume that pointers are never more than 64 bits wide.
+  // Assume that pointers are never more than 64 bits wide, and only use this
+  // for the middle type. Otherwise we could end up folding away illegal
+  // bitcasts between address spaces with different sizes.
   IntegerType *FakeIntPtrTy = Type::getInt64Ty(DstTy->getContext());
 
   // Let CastInst::isEliminableCastPair do the heavy lifting.
   return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
-                                        FakeIntPtrTy, FakeIntPtrTy,
-                                        FakeIntPtrTy);
+                                        0, FakeIntPtrTy, 0);
 }
 
 static Constant *FoldBitCast(Constant *V, Type *DestTy) {