https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115118
Bug ID: 115118
Summary: [15 Regression] 5-13% slowdown of 470.lbm on zen4
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: missed-optimization, needs-bisection
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=992.240.0
there is a 13% (only 5% on another machine where i replicated this) slowdown of
the 470.lbm SPEC 2006 benchmark between commits
r15-311-gf6ce85502eb2e4
r15-334-gbaf1a677955a4d
This happens on Zen4 CPUs. I haven't seen the regression anywhere else. The
compilation options are -Ofast -march=native -flto
Here is also a graph with GCC 14 plotted to show that this is a 15 regression:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.3=1017.240.0&plot.4=992.240.0&;
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)
