[clang] [Clang] Re-write codegen for atomic_test_and_set and atomic_clear (PR #120449)

[Eli Friedman via cfe-commits]

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@@ -1977,15 +1977,15 @@ def AtomicNandFetch : AtomicBuiltin {
   let Prototype = "void(...)";
 }
 
-def AtomicTestAndSet : Builtin {
+def AtomicTestAndSet : AtomicBuiltin {
   let Spellings = ["__atomic_test_and_set"];
-  let Attributes = [NoThrow];
+  let Attributes = [NoThrow, CustomTypeChecking];
   let Prototype = "bool(void volatile*, int)";
 }
 
-def AtomicClear : Builtin {
+def AtomicClear : AtomicBuiltin {
   let Spellings = ["__atomic_clear"];
-  let Attributes = [NoThrow];
+  let Attributes = [NoThrow, CustomTypeChecking];
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efriedma-quic wrote:

For builtins that use custom type checking, we usually use something like `void(...)` instead of `void(void volatile*, int)`.  But as far as I remember, we ignore the signature anyway, so it doesn't matter very much.

https://github.com/llvm/llvm-project/pull/120449