diff options
| -rw-r--r-- | clang/CodeGen/CGExprScalar.cpp | 16 | ||||
| -rw-r--r-- | clang/test/CodeGen/exprs.c | 6 |
2 files changed, 20 insertions, 2 deletions
diff --git a/clang/CodeGen/CGExprScalar.cpp b/clang/CodeGen/CGExprScalar.cpp index e7f58bb4689..820234033b0 100644 --- a/clang/CodeGen/CGExprScalar.cpp +++ b/clang/CodeGen/CGExprScalar.cpp @@ -767,8 +767,20 @@ Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) { 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) { diff --git a/clang/test/CodeGen/exprs.c b/clang/test/CodeGen/exprs.c index 91153691733..16b63f8883b 100644 --- a/clang/test/CodeGen/exprs.c +++ b/clang/test/CodeGen/exprs.c @@ -17,3 +17,9 @@ void *test(int *i) { _Bool test2b; int test2() {if (test2b);} +// PR1921 +int test3() { + const unsigned char *bp; + bp -= (short)1; +} + |
