https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124826
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- bitint lowering does handle BIT_FIELD_REFs specially, since PR114157. But in this case it actually isn't handled as BIT_FIELD_REF, but as load, because gimple_assign_load_p is true on that.
