https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120895
--- Comment #22 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Further note, the differences between alignof and __alignof don't apply for types with user aligned attribute (or alignas), but are present not just for say 32-byte vectors when AVX is not enabled or 64-byte vectors when AVX512F is not enabled, but also e.g. for long long type on ia32, there e.g. long long members are just 4 byte aligned per ABI and hw doesn't need bigger alignment than 4 bytes, but still e.g. namespace scope variables with that type will be 8 byte aligned.
