[clang] [CIR] Add X86 prefetch builtins (PR #168051)

[Hendrik Hübner via cfe-commits]

================
@@ -1272,9 +1272,6 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
     llvm_unreachable("Bad evaluation kind in EmitBuiltinExpr");
   }
 
-  cgm.errorNYI(e->getSourceRange(),
----------------
HendrikHuebner wrote:

This check is now handled in `CIRGenBuiltinX86`, so we can return empty values without triggering the NYI error

https://github.com/llvm/llvm-project/pull/168051