https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122777
Bug ID: 122777
Summary: [16 Regression] 5-7% slowdown of 454.calculix on AMD
Zen{4,5} since r16-5258-g1d8e2d51e5c5cb
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pheeck at gcc dot gnu.org
CC: pinskia 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=1283.170.0
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=991.170.0
there was a 7% exec time slowdown of the 454.calculix SPEC 2006
benchmark when compiled with -Ofast -march=native -flto -fprofile-use on an AMD
Zen5 machine. The same slowdown but only 5% happened on AMD Zen4. I bisected
it to r16-5258-g1d8e2d51e5c5cb.
Author: Andrew Pinski <[email protected]>
AuthorDate: Tue Nov 11 11:29:38 2025 -0800
Commit: Andrew Pinski <[email protected]>
CommitDate: Thu Nov 13 12:56:54 2025 -0800
cfgcleanup: Support merging forwarder blocks with phis [PR122493]
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)
