https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93945
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- For 9.x all we need is add && multiple_p (ref->size, BITS_PER_UNIT) because the code doesn't attempt to handle loads or stores that aren't byte aligned and whole byte sized. I found this by code inspection when trying to add trunk support for arbitrary load bit offset or ref->size.
