[Bug tree-optimization/78005] New: [7 Regression] 172.mgrid miscompares

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78005

            Bug ID: 78005
           Summary: [7 Regression] 172.mgrid miscompares
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---
            Target: x86_64-*-*, i?86-*-*

With -Ofast on core-avx2 and bdver2, works fine with generic tuning.  Last
known good rev. is r241084, first kown bad r241120.