finish off codegen support for sub of pointer to functions,
finishing off rdar://6520707
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64295 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index b9dcc07..a94eef1 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -965,8 +965,9 @@
uint64_t ElementSize;
- // Handle GCC extension for pointer arithmetic on void* types.
- if (LHSElementType->isVoidType()) {
+ // Handle GCC extension for pointer arithmetic on void* and function pointer
+ // types.
+ if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) {
ElementSize = 1;
} else {
ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8;
@@ -977,6 +978,10 @@
RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub");
+ // Optimize out the shift for element size of 1.
+ if (ElementSize == 1)
+ return BytesBetween;
+
// HACK: LLVM doesn't have an divide instruction that 'knows' there is no
// remainder. As such, we handle common power-of-two cases here to generate
// better code. See PR2247.