[clang] [clang] Implement __builtin_rotate{left,right}g (PR #160259)

[Nikolas Klauser via cfe-commits]

================
@@ -767,12 +767,24 @@ def RotateLeft : BitInt8_16_32_64BuiltinsTemplate, Builtin {
   let Prototype = "T(T, T)";
 }
 
+def RotateLeftg : Builtin {
+  let Spellings = ["__builtin_rotateleftg"];
+  let Attributes = [NoThrow, Const, Constexpr, CustomTypeChecking];
+  let Prototype = "void(...)";
+}
+
 def RotateRight : BitInt8_16_32_64BuiltinsTemplate, Builtin {
   let Spellings = ["__builtin_rotateright"];
   let Attributes = [NoThrow, Const, Constexpr];
   let Prototype = "T(T, T)";
 }
 
+def RotateRightg : Builtin {
+  let Spellings = ["__builtin_rotaterightg"];
+  let Attributes = [NoThrow, Const, Constexpr, CustomTypeChecking];
----------------
philnik777 wrote:

There should be one though. Otherwise these builtins are much less useful IMO. Given that the constant size builtins are constexpr it should also be fairly trivial to implement.

https://github.com/llvm/llvm-project/pull/160259