[Bug target/125662] New: [17 Regression] 4% slowdown of blender_r on x86

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125662

            Bug ID: 125662
           Summary: [17 Regression] 4% slowdown of blender_r on x86
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Keywords: missed-optimization, needs-bisection
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jmelcr at gcc dot gnu.org
            Blocks: 26163
  Target Milestone: ---
              Host: x86_64-suse-linux
            Target: x86_64-suse-linux
             Build: x86_64-suse-linux

As seen here

https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=796.487.0

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

r17-212-g631427fc512fba
r17-338-g6112538b060d8a

when compiled with -Ofast -march=native -g -flto=16 on an Intel Ice Lake (3rd
generation Xeon) machine.

This is a regression against GCC 16 (see the short purple line). See the
comparison
here:

https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=814.487.0&plot.1=851.487.0&plot.2=835.487.0&plot.3=916.487.0&plot.4=1097.487.0&plot.5=1204.487.0&plot.6=1513.487.0&plot.7=796.487.0&;


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26163
[Bug 26163] [meta-bug] missed optimization in SPEC (2026, 2k17, 2k and 2k6 and
95)