https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98221
--- Comment #3 from Andreas Krebbel <krebbel at gcc dot gnu.org> --- tree-vect-loop-manip.c: vect_maybe_permute_loop_masks also emits VEC_UNPACKS_HI/LO dependent on BYTES_BIG_ENDIAN. What is the expectation wrt the meaning of hi/lo in RTL standard names? I couldn't find it clearly documented for this either. Well, for things like 'smulm3_highpart' we say it is about the 'most significant half' but I don't see anything for the vector hi/lo.