https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124147
--- Comment #2 from Robin Dapp <rdapp at gcc dot gnu.org> --- (In reply to Jeffrey A. Law from comment #1) > It looks like expand_vector_broadcast is failing, presumably due to > something thead vector related. Anyway, that fails returning NULL which we > then dutifully pass to emit_move_insn as the source objects and boom! Yes is theadvector related. The expander expects to have QImode vector modes available with the same number of units as the incoming mask vector. Mask vectors are often small, in this case < 16 elements. This necessitates a fractional-LMUL mode which theadvector doesn't support. So, again, a workaround for theadvector is needed.
