[clang] [libcxx] [Clang] Add __builtin_invoke and use it in libc++ (PR #116709)

[Nikolas Klauser via cfe-commits]

================
@@ -5406,6 +5408,101 @@ ExprResult Sema::ConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo,
                                    RParenLoc, CurFPFeatureOverrides());
 }
 
+ExprResult Sema::BuiltinInvoke(CallExpr *TheCall) {
+  auto Loc = TheCall->getBeginLoc();
+  auto Args = MutableArrayRef(TheCall->getArgs(), TheCall->getNumArgs());
+  assert(llvm::none_of(Args,
----------------
philnik777 wrote:

```
template <class T>
auto test(T v) {
  return __builtin_invoke(v);
}
```
should do the trick, right? Assuming I've set things up correctly on my end, this does not trigger the assert here.

https://github.com/llvm/llvm-project/pull/116709