[Bug tree-optimization/87166] New: 454.calculix benchmark is much slower on -Ofast with PGO or LTO

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87166

            Bug ID: 87166
           Summary: 454.calculix benchmark is much slower on -Ofast with
                    PGO or LTO
           Product: gcc
           Version: 9.0
            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
            Blocks: 26163
  Target Milestone: ---
              Host: x86_64-linux-gnu

Seen on multiple GCC releases and different CPUs (Intel Haswell and AMD Zen).
For PGO it goes from 197.860 to 455.025 seconds.


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)