[Bug target/88494] New: [9 Regression] polyhedron 10% mdbx runtime regression

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88494

            Bug ID: 88494
           Summary: [9 Regression] polyhedron 10% mdbx runtime regression
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

Between r266526 (good) and r266587 (bad) polyhedron mdbx runtime regressed from
6s to 6.7s on a Haswell machine with -Ofast -march=native -funroll-loops.

https://gcc.opensuse.org/gcc-old/c++bench-czerny/pb11/pb11-summary.txt-2-0.html

There are not many interesting changes in the revision range but I sofar didn't
reproduce elsewhere nor bisected the above revs.