[Bug tree-optimization/123239] New: [16 Regression] 4% slowdown of imagick_r on Aarch64 with PGO

[jmelcr at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123239

            Bug ID: 123239
           Summary: [16 Regression] 4% slowdown of imagick_r on Aarch64
                    with PGO
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Keywords: missed-optimization, needs-bisection
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jmelcr at gcc dot gnu.org
                CC: pheeck at gcc dot gnu.org
            Blocks: 26163
  Target Milestone: ---
              Host: aarch64-gnu-linux
            Target: aarch64-gnu-linux

As seen here

https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=583.507.0

there was a 4% exec time slowdown of the imagick_r SPEC 2017 benchmark between
commits

r16-5977-gcf22e30f0cfae6
r16-6113-g03a1951a30c4f5

when compiled with -Ofast -march=native with PGO on an Ampere Altra Neoverse N1
machine.
This is a regression against GCC 15. See the comparison
here:

https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=639.507.0&plot.1=684.507.0&plot.2=667.507.0&plot.3=655.507.0&plot.4=623.507.0&plot.5=608.507.0&plot.6=772.507.0&plot.7=883.507.0&plot.8=1081.507.0&plot.9=1237.507.0&plot.10=583.507.0&;


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)