https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88101
--- Comment #4 from Thomas Rodgers <rodgertq at gcc dot gnu.org> --- (In reply to andysem from comment #2) > Another use case is C++20 atomic_ref, which may be bound to an object whose > padding bits are in indeterminate state. An intrinsic to clear padding bits > without altering the object value could be useful. Having now implemented atomic<T>::wait for libstdc++, I think the intrinsic to clear padding bits before calling __builtin_memcmp for generic (trivially copyable) T's is the right approach.
