https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118957
Bug ID: 118957
Summary: 5-9% slowdown of 511.povray_r and 453.povray on x86_64
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: pheeck at gcc dot gnu.org
Blocks: 26163
Target Milestone: ---
Host: x86_64-linux
Target: x86_64-linux
As seen here
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=968.467.0
there was a 5% exec time slowdown of the 511.povray_r SPEC 2017 benchmark
between commits
r15-7324-g969c30885558d0
r15-7437-g64d8ea056a5c33
when run with -O2 -march=generic -flto PGO on an AMD Zen4 machine.
Similar slowdowns around that time:
5% slowdown of 511.povray_r on Intel Ice Lake (3rd generation Xeon)
with -O2 -march=native -flto
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=795.467.0
9% slowdown of 453.povray (SPEC 2006) on AMD Zen4
with -O2 -march=generic -flto PGO
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=960.160.0
3% slowdown of 511_povray_r on AMD Zen5
with -O2 -march=generic -flto PGO
---
Here is a graph (for the 9% case) showing that this isn't a regression over
GCC14
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.3=1012.160.0&plot.4=960.160.0&;
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)
