[Bug target/111616] New: On Zen2 7% 519.lbm_r regression between g:1d17d58c284fa8c3 (2023-09-14 02:39) and g:c8e9a75085f9725c (2023-09-18 13:09)

[fkastl at suse dot cz via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111616

            Bug ID: 111616
           Summary: On Zen2 7% 519.lbm_r regression between
                    g:1d17d58c284fa8c3 (2023-09-14 02:39) and
                    g:c8e9a75085f9725c (2023-09-18 13:09)
           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
                CC: mjambor at suse dot cz
  Target Milestone: ---
              Host: x86_64-linux
            Target: x86_64-linux

On x86_64 AMD Zen2 machine with Ofast LTO PGO march=native mtune=native between
commits g:1d17d58c284fa8c3 (2023-09-14 02:39) and g:c8e9a75085f9725c
(2023-09-18 13:09) there is a 519.lbm_r 7% execution time regression.

Here is a plot of recent measurements:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=286.477.0

I confirmed this on another Zen2 machine. This time I measured 9% slowdown.