[Bug libstdc++/114865] [13/14/15 Regression] std::atomic::compare_exchange_strong seems to hang under GCC 13 for C++11

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114865

--- Comment #26 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think I should push the partial solution now anyway. It's better than what we
do today, as at least it will work correctly for programs that don't initialize
an atomic in C++11 objects and then use CAS in C++14/17/20/... objects.

Whether to pessimize CAS for all types with padding can be decided later.