https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108734
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- What are you actually trying to do here? If you're trying to provide your own definitions for the atomic built-ins then obviously you need to know platform-specific details, including whether that operation is already expanded without emitting a library call. If you're trying to do something else, maybe testing the macro __GCC_ATOMIC_LLONG_LOCK_FREE==2 can help.
