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

[Aaron Ballman via cfe-commits]

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@@ -4972,3 +4972,59 @@ def NoTrivialAutoVarInit: InheritableAttr {
   let Documentation = [NoTrivialAutoVarInitDocs];
   let SimpleHandler = 1;
 }
+
+def Atomic : StmtAttr {
+  let Spellings = [Clang<"atomic">];
+  let Args = [
+    EnumArgument<"NoRemoteMemory", "NoRemoteMemoryTy", /*IsString*/ false,
+      ["no_remote_memory", "!no_remote_memory", ""],
+      ["NoRemoteMemoryOn", "NoRemoteMemoryOff", "NoRemoteMemoryUnset"]>,
+    EnumArgument<"NoFineGrainedMemory", "NoFineGrainedMemoryTy", /*IsString*/ false,
+      ["no_fine_grained_memory", "!no_fine_grained_memory", ""],
+      ["NoFineGrainedMemoryOn", "NoFineGrainedMemoryOff", "NoFineGrainedMemoryUnset"]>,
+    EnumArgument<"IgnoreDenormalMode", "IgnoreDenormalModeTy", /*IsString*/ false,
+      ["ignore_denormal_mode", "!ignore_denormal_mode", ""],
+      ["IgnoreDenormalModeOn", "IgnoreDenormalModeOff", "IgnoreDenormalModeUnset"]>
+  ];
+  let Subjects = SubjectList<[CompoundStmt], ErrorDiag, "compound statements">;
+  let HasCustomParsing = 1;
+  let Documentation = [Undocumented];
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AaronBallman wrote:

No new, undocumented attributes, please.

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