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From: "fkastl at suse dot cz" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/112879] New: [14 Regression] 4% exec time regression of
 525.x264_r on AMD Zen4
Date: Wed, 06 Dec 2023 11:09:27 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: needs-bisection
X-Bugzilla-Severity: normal
X-Bugzilla-Who: fkastl at suse dot cz
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112879

            Bug ID: 112879
           Summary: [14 Regression] 4% exec time regression of 525.x264_r
                    on AMD Zen4
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: needs-bisection
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fkastl at suse dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

There's a 4% slowdown of 525.x264_r on AMD Zen4 between commits

g:af7fa3135b6b046f

g:e85c596ae2d1e5f5

Here is a plot showing this regression:

https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=3D958.377.0

I've seen this regression on two different Zen4 machines but haven't observ=
ed
it on machines with different architecture.=