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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96134 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 18 insertions, 5 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 43419eb9fc..e501ddc4b8 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/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);
       
diff --git a/test/Transforms/InstCombine/objsize.ll b/test/Transforms/InstCombine/objsize.ll
index 646baa0de0..dbc7d31c39 100644
--- a/test/Transforms/InstCombine/objsize.ll
+++ b/test/Transforms/InstCombine/objsize.ll
@@ -63,4 +63,13 @@ entry:
   unreachable
 }
 
+@.str5 = private constant [9 x i32] [i32 97, i32 98, i32 99, i32 100, i32 0, i32
+ 101, i32 102, i32 103, i32 0], align 4 ;
+define i32 @test2() nounwind {
+; CHECK: @test2
+; CHECK-NEXT: ret i32 34
+  %1 = call i32 @llvm.objectsize.i32(i8* getelementptr (i8* bitcast ([9 x i32]* @.str5 to i8*), i32 2), i1 false)
+  ret i32 %1
+}
+
 declare i32 @llvm.objectsize.i32(i8*, i1) nounwind readonly
\ No newline at end of file