[clang] Add clang atomic control options and attribute (PR #114841)

[Yaxun Liu via cfe-commits]

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@@ -625,6 +625,43 @@ static Attr *handleHLSLControlFlowHint(Sema &S, Stmt *St, const ParsedAttr &A,
   return ::new (S.Context) HLSLControlFlowHintAttr(S.Context, A);
 }
 
+static Attr *handleAtomicAttr(Sema &S, Stmt *St, const ParsedAttr &A,
+                              SourceRange Range) {
+  if (!isa<CompoundStmt>(St)) {
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yxsamliu wrote:

You are right. The CompoundStmt check is not necessary since equivalent check is done in Parser. Will remove this check here. 

https://github.com/llvm/llvm-project/pull/114841