https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78804
--- Comment #9 from Oleg Endo <olegendo at gcc dot gnu.org> --- Created attachment 41982 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41982&action=edit Proposed patch I'd propose to remove the FLOAT_BIT_ORDER_MISMATCH stuff altogether. It's more portable to use shift-and-mask than bitfields. Bitfields depend on too many things, like BITS_BIG_ENDIAN, BIGGEST_FIELD_ALIGNMENT, .... The patch fixes the issue on RX.