Fix PR1921 by promoting negative indices to intptrty.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@46599 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CodeGen/CGExprScalar.cpp b/CodeGen/CGExprScalar.cpp
index e7f58bb..8202340 100644
--- a/CodeGen/CGExprScalar.cpp
+++ b/CodeGen/CGExprScalar.cpp
@@ -767,8 +767,20 @@
assert(!isa<llvm::PointerType>(Ops.RHS->getType()) &&
"ptr-ptr shouldn't get here");
// FIXME: The pointer could point to a VLA.
- Value *NegatedRHS = Builder.CreateNeg(Ops.RHS, "sub.ptr.neg");
- return Builder.CreateGEP(Ops.LHS, NegatedRHS, "sub.ptr");
+ Value *Idx = Builder.CreateNeg(Ops.RHS, "sub.ptr.neg");
+
+ unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
+ if (Width < CGF.LLVMPointerWidth) {
+ // Zero or sign extend the pointer value based on whether the index is
+ // signed or not.
+ const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth);
+ if (Ops.E->getRHS()->getType().getCanonicalType()->isSignedIntegerType())
+ Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext");
+ else
+ Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext");
+ }
+
+ return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr");
}
Value *ScalarExprEmitter::VisitBinSub(const BinaryOperator *E) {