[Bug target/115856] New: [15 Regression] 7% slowdown of 433.milc on Zen3

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115856

            Bug ID: 115856
           Summary: [15 Regression] 7% slowdown of 433.milc on Zen3
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: 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=469.70.0

there was a 7% exec time slowdown of the 433.milc SPEC 2006 benchmark between
commits

r15-1731-g30ad2fafa9ab24
r15-1735-ge62ea4fb8ffcab

when run with -O2 -march=generic -flto on an AMD Zen3 machine. I have not seen
the regression on other microarchitectures.


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)