https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102377
--- Comment #2 from Thomas Rodgers <rodgertq at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #1) > The reason we don't see it in every test is that this one uses: > > // { dg-options "-Wsystem-headers -Wnarrowing" } > > But I think the warning is pointing out a real issue. Since the interference > sizes vary with -mtune options, we shouldn't use them in <atomic>, since > that's defining a public ABI (or will be, once our C++20 support is > non-experimental). Agreed.