[Bug middle-end/84214] New: recip and slp passes conflict

[clyon at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84214

            Bug ID: 84214
           Summary: recip and slp passes conflict
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: clyon at gcc dot gnu.org
  Target Milestone: ---

In https://gcc.gnu.org/ml/gcc-patches/2018-01/msg02443.html I reported a
regression on aarch64 in gcc.dg/cse_recip.c.

In https://gcc.gnu.org/ml/gcc-patches/2018-01/msg02446.html, richi explained
that a possible fix would be to make the recip pass run before vectorization.

It would fix the testcase by preventing vectorization, but since we are in
stage4, it's a bit late to make such a change.