https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78821
--- Comment #21 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Created attachment 42660 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42660&action=edit gcc8-pr78821-i386.patch Untested patch for the -mmovbe movbew loads/stores. Note, is there any particular reason why we don't use for AT&T syntax w/l/q suffixes for movbe? At least looking at binutils testsuite, it covers both movbe without suffix and movbe[wlq]. On the other side, for bswap insn there are no suffixes.