[MS Volatile] Don't make volatile loads/stores to underaligned objects atomic
Underaligned atomic LValues require libcalls which MSVC doesn't have.
MSVC doesn't seem to consider such operations as requiring a barrier
anyway.
This fixes PR27843.
llvm-svn: 270576
diff --git a/clang/lib/CodeGen/CGAtomic.cpp b/clang/lib/CodeGen/CGAtomic.cpp
index aa5a32d..7b747c1 100644
--- a/clang/lib/CodeGen/CGAtomic.cpp
+++ b/clang/lib/CodeGen/CGAtomic.cpp
@@ -1274,31 +1274,11 @@
bool IsVolatile = LV.isVolatile() || hasVolatileMember(LV.getType());
// An atomic is inline if we don't need to use a libcall.
bool AtomicIsInline = !AI.shouldUseLibcall();
- return IsVolatile && AtomicIsInline;
-}
-
-/// An type is a candidate for having its loads and stores be made atomic if
-/// we are operating under /volatile:ms *and* we know the access is volatile and
-/// performing such an operation can be performed without a libcall.
-bool CodeGenFunction::typeIsSuitableForInlineAtomic(QualType Ty,
- bool IsVolatile) const {
- // The operation must be volatile for us to make it atomic.
- if (!IsVolatile)
- return false;
- // The -fms-volatile flag must be passed for us to adopt this behavior.
- if (!CGM.getCodeGenOpts().MSVolatile)
- return false;
-
- // An atomic is inline if we don't need to use a libcall (e.g. it is builtin).
- if (!getContext().getTargetInfo().hasBuiltinAtomic(
- getContext().getTypeSize(Ty), getContext().getTypeAlign(Ty)))
- return false;
-
// MSVC doesn't seem to do this for types wider than a pointer.
- if (getContext().getTypeSize(Ty) >
+ if (getContext().getTypeSize(LV.getType()) >
getContext().getTypeSize(getContext().getIntPtrType()))
return false;
- return true;
+ return IsVolatile && AtomicIsInline;
}
RValue CodeGenFunction::EmitAtomicLoad(LValue LV, SourceLocation SL,