http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59569
--- Comment #8 from Bingfeng Mei <bmei at broadcom dot com> --- Sorry for the regression. The assertion happens if storing a constant value with negative step. Doing permutation of constant is not the best optimization here. So the easy way to fix is to skip vectorizing this statement in the same way as before the patch. Or maybe better way is to form a constant vector to store.