[Bug tree-optimization/59594] [4.9 Regression] wrong code (by tree vectorizer) at -O3 on x86_64-linux-gnu

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59594

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
You're right, r206180 fixed this (i.e. that it FAILs at runtime even for
-mtune=generic).  In any case, sounds like this is a problem in determination
of the aliasing, we should have refused to vectorize this (of course unless we
are smart enough to find out all the b[a] = 1; stores but the b[0] = 1; is
redundant, but I suppose the vectorizer isn't the right place to do that
optimization.