[Bug tree-optimization/82426] Missed tree-slp-vectorization on -O2 and -O3

[linux at carewolf dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82426

--- Comment #3 from Allan Jensen <linux at carewolf dot com> ---
Note it appears the fact it can do it at all in -Os is new in gcc 7