https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106069
--- Comment #27 from Segher Boessenkool <segher at gcc dot gnu.org> --- IMO what vec_select calls element 0 is always in the first argument of the vec_concat it works on, in BE as well as LE. But yes this is quite underdefined in our documentation, and who know what is actually implemented, in targets as well as in generic code :-(
