https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63679
--- Comment #26 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I'd say it is a bug in the backend, if you want to override some expansion, you'd better add some target hook for that, rather than messing up with MOVE_BY_PIECES and setting it to clearly bogus values.
