[libcxx-commits] [PATCH] D149313: [libc++] Use __is_convertible built-in when available

Thu Apr 27 14:21:26 PDT 2023

mcgrathr added inline comments.

================
Comment at: libcxx/include/__type_traits/is_convertible.h:27

-#if __has_builtin(__is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
+#if __has_builtin(__is_convertible) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
+
----------------
philnik wrote:
> mcgrathr wrote:
> > philnik wrote:
> > > Please add a `//TODO: Remove the #else branch once GCC 13 is used in the CI`.
> > I'm not clear on what the TODO intends to be done later.
> > Are you saying that you'll remove the fallback for the case of no built-in at all?
> > I imagine that would break compatibility with many extant GCC versions that don't have either built-in, wouldn't it?
> > 
> Yes, that's exactly what I'm saying. We only support the latest released GCC and the last two Clang versions and the one in the same release. People mostly use very recent compiler versions with libc++. Supporting older compilers would be a lot of work for very little benefit.
Understood.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D149313/new/

https://reviews.llvm.org/D149313