[Bug tree-optimization/107946] New: [13 Regression] 507.cactuBSSN_r regresses by ~9% on znver3 with PGO since r13-3875-g9e11ceef165bc0

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107946

            Bug ID: 107946
           Summary: [13 Regression] 507.cactuBSSN_r regresses by ~9% on
                    znver3 with PGO since r13-3875-g9e11ceef165bc0
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: jamborm at gcc dot gnu.org, rguenth at gcc dot gnu.org
            Blocks: 26163
  Target Milestone: ---

The revision r13-3875-g9e11ceef165bc0 was supposed to speed up the benchmark,
but it makes it slower w/ -O2 -flto and PGO:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=694.437.0

Similar regression can be seen w/o LTO as well:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=463.437.0


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26163
[Bug 26163] [meta-bug] missed optimization in SPEC (2k17, 2k and 2k6 and 95)