https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114801
--- Comment #20 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Pretending a boolean mode has non-boolean value is invalid RTL (or GIMPLE). So, the rtx-vector-builder.cc change looks wrong to me. If you want to handle the predicate elements with element values other than all 0s or all 1s some special way, like handling it as a predication, then I think you should stop pretending it is a boolean mode, use partial int mode or something similar instead. But such a change doesn't feel safe for 14.1.
