TImode/OImode/XImode support load and store with vector registers. But by_pieces_ninsns determines the widest mode with MAX_FIXED_MODE_SIZE which is limited by integer registers. There is a patch to update alignment_for_piecewise_move to remove the MAX_FIXED_MODE_SIZE restriction: https://gcc.gnu.org/ml/gcc-patches/2016-04/msg01506.html But there is a concern for simplify_immed_subreg: https://gcc.gnu.org/ml/gcc-patches/2016-04/msg01527.html
Isn't this fixed now?
Dup. *** This bug has been marked as a duplicate of bug 90773 ***