http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45429
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-17 10:25:40 UTC --- And the reason why it only shows up on ia64 is because it uses vectorization factor 2 instead of 4 that is used on x86_64/i386+sse2. With: int id[16][16][17] id[i][1][0+1] is actually aligned to 2 * sizeof (int), so no peeling is needed to align it.