[clang] [CIR] Upstream ClearCacheOp support for __builtin___clear_cache (PR #178260)

[Andy Kaylor via cfe-commits]

================
@@ -1080,8 +1080,16 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
   }
   case Builtin::BI__builtin_readcyclecounter:
   case Builtin::BI__builtin_readsteadycounter:
-  case Builtin::BI__builtin___clear_cache:
     return errorBuiltinNYI(*this, e, builtinID);
+  case Builtin::BI__builtin___clear_cache: {
+    mlir::Type voidTy = cir::VoidType::get(&getMLIRContext());
+    mlir::Value begin =
+        builder.createPtrBitcast(emitScalarExpr(e->getArg(0)), voidTy);
+    mlir::Value end =
+        builder.createPtrBitcast(emitScalarExpr(e->getArg(1)), voidTy);
----------------
andykaylor wrote:

```suggestion
    mlir::Value begin =
        builder.createPtrBitcast(emitScalarExpr(e->getArg(0)), cgm.voidTy);
    mlir::Value end =
        builder.createPtrBitcast(emitScalarExpr(e->getArg(1)), cgm.voidTy);
```

https://github.com/llvm/llvm-project/pull/178260