Fix a problem where we had bitcasted operands that gave us

odd offsets since the bitcasted pointer size and the offset pointer
size are going to be different types for the GEP vs base object.

llvm-svn: 96134

1 files changed, 9 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 43419eb9fc0..e501ddc4b85 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -334,17 +334,21 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
       // Make sure we're not a constant offset from an external
       // global.
       Value *Operand = GEP->getPointerOperand();
+      Operand = Operand->stripPointerCasts();
       if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Operand))
         if (!GV->hasDefinitiveInitializer()) break;
       
-      // Get what we're pointing to and its size.
-      const PointerType *PT = 
+      // Get what we're pointing to and its size. 
+      const PointerType *BaseType = 
         cast<PointerType>(Operand->getType());
-      size_t Size = TD->getTypeAllocSize(PT->getElementType());
+      size_t Size = TD->getTypeAllocSize(BaseType->getElementType());
       
-      // Get the current byte offset into the thing.
+      // Get the current byte offset into the thing. Use the original
+      // operand in case we're looking through a bitcast.
       SmallVector<Value*, 8> Ops(CE->op_begin()+1, CE->op_end());
-      size_t Offset = TD->getIndexedOffset(PT, &Ops[0], Ops.size());
+      const PointerType *OffsetType =
+        cast<PointerType>(GEP->getPointerOperand()->getType());
+      size_t Offset = TD->getIndexedOffset(OffsetType, &Ops[0], Ops.size());
 
       assert(Size >= Offset);