https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98884
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> --- x86-64 is handled correctly according to the psABI, see https://gitlab.com/x86-psABIs/x86-64-ABI/-/blob/master/x86-64-ABI/low-level-sys-info.tex The empty classes will end up with NO_CLASS and thus aren't passed at all.
