https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71945
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #3) > The __atomic_fetch_add built-in on signed integers is required to wrap like > unsigned integers without UB, but we should check that all our > target-specific implementations of __exchange_and_add (and > __exchange_and_add_single) have that property too. We also need to make sure that the _Sp_counted_base<_S_single> specialization which uses plain non-atomic increments and decrements uses unsigned arithmetic to be free of UB when going from INT_MAX to INT_MIN.
