[Bug tree-optimization/98868] New: [8/9/10/11 Regression] polyhedron rnflow.f90 regression since r8-2555-g344be1fd47d7d64e

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98868

            Bug ID: 98868
           Summary: [8/9/10/11 Regression] polyhedron rnflow.f90
                    regression since r8-2555-g344be1fd47d7d64e
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
  Target Milestone: ---

Since the revision the benchmark is much slower:

$ gfortran rnflow.f90 -Ofast -march=znver1 && time ./a.out >/dev/null

0m7.690s -> 0m13.121s

One can see it here:
https://lnt.opensuse.org/db_default/v4/CPP/graph?plot.0=194.791.0&plot.1=188.791.0&plot.2=202.791.0&plot.3=154.791.0&plot.4=245.791.0&plot.5=171.791.0&