[clang] [Clang] Re-write codegen for atomic_test_and_set and atomic_clear (PR #121943)

[James Y Knight via cfe-commits]

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@@ -3963,8 +3995,8 @@ ExprResult Sema::BuildAtomicExpr(SourceRange CallRange, SourceRange ExprRange,
     return ExprError();
   }
 
-  if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context) &&
-      !AtomTy->isScalarType()) {
+  if (!IsC11 && Form != TestAndSet && Form != Clear &&
+      !AtomTy.isTriviallyCopyableType(Context) && !AtomTy->isScalarType()) {
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jyknight wrote:

And then you can remove this diff, because the `AtomTy` will be (correctly) `char`.

https://github.com/llvm/llvm-project/pull/121943