https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109398
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- So this might not be a clang extension after all. see https://github.com/llvm/llvm-project/issues/83658 (and DE-137 discussion in the meeting minutes: https://www.open-std.org/JTC1/sc22/wg14/www/docs/n3167.pdf ).
