https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91623
--- Comment #6 from Marc Glisse <glisse at gcc dot gnu.org> --- For the missed constant folding, it seems that we end up in fold_vec_perm, with type a vector of "long long", while arg0 and arg1 are vectors of "long", and we give up because of the early check "TREE_TYPE (TREE_TYPE (arg0)) != TREE_TYPE (type)". I don't know if the check should be relaxed, or if the bug is earlier and we shouldn't have reached this place with such different types...
