https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119325
--- Comment #15 from Richard Biener <rguenth at gcc dot gnu.org> ---
maybe
#define RESIZE_VECTOR(to_t, from) \
({ \
__auto_type __from = (from); \
to_t __to;
memcpy (&__to, &__from, MIN (sizeof (to_t), sizeof (from))); \
__to; \
})
