https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115463
Bug ID: 115463
Summary: 526.blender_r regressed 5% on Zen2 with -Ofast -flto
-march=native since r15-1058-gc989e59fc99d99
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jamborm at gcc dot gnu.org
CC: hongyuw at gcc dot gnu.org
Blocks: 26163
Target Milestone: ---
The run-time of benchmark 526.blender_r from SPEC INTrate 2017 has
regressed 5.3% on Zen2-based CPUs when compiled with -Ofast -flto
-march-mnative since r15-1058-gc989e59fc99d99 (Hongyu Wang: [APX CCMP]
Support APX CCMP). I was not expecting this patch to cause any
changes in code generated for non-APX CPUs but I have double checked.
The regression can be seen/tracked at
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=287.487.0
There are also smaller regressions that happened around the same time:
- zen2 -Ofast -flto -fprofile-use -march=native: 3%
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=286.487.0
- skylake -Ofast -flto -march=native: 4%
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=801.487.0
- skylake -Ofast -flto -fprofile-use -march=native: 3%
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=792.487.0
- zen3 -Ofast -flto -march=native: 2%
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=475.487.0
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)
