[Bug target/109130] New: 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU with PGO, LTO, -Ofast and -march=native

[Bug target/109130] New: 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU with PGO, LTO, -Ofast and -march=native

[jamborm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109130

            Bug ID: 109130
           Summary: 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU
                    with PGO, LTO, -Ofast and -march=native
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jamborm at gcc dot gnu.org
                CC: tnfchris at gcc dot gnu.org
            Blocks: 26163
  Target Milestone: ---
              Host: aarch64-suse-linux
            Target: aarch64-suse-linux

LNT shows what looks like a clear recent 6.5% regression on the
464.h264ref benchmark from SPEC 2006 CPU suite when compiled with
PGO, LTO, -Ofast and -march=native on a Neoverse-N1 CPU:

  https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=586.220.0

In the same time period, I cannot (immediately) see any similar
regressions on any other CPU (all others that we monitor are x86_64)
or option combination.

Unfortunately I don't have the time and resources to further
investigate, but the commit range bad177e848787258..2fc55f51f9953b45
includes 8e26ac4749c (AArch64: Fix codegen regressions around tbz),
among other things.


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)

[Bug target/109130] 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU with PGO, LTO, -Ofast and -march=native

[tnfchris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109130

--- Comment #1 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
I can't reproduce that. on a Neoverse-N1 I see between those two commits:

./bench-compare.sh 2fc55f51f99 bad177e8487
A       1457 files
D       0 files
M       0 files
Extracted 'loose/2fc55f51f99:2fc55f51f99'
A       1457 files
D       0 files
M       0 files
Extracted 'loose/bad177e8487:bad177e8487'

difference: 0.083458946886789971215830257097%

Compiled with -Ofast -march=native -g -flto=auto and PGO enabled. as extracted
from
https://lnt.opensuse.org/db_default/v4/SPEC/34263?show_stddev=yes&show_all=yes&show_all_samples=yes&num_comparison_runs=0&test_filter=&test_min_value_filter=&aggregation_fn=min&MW_confidence_lv=0.05&compare_to=34183&baseline=23835&submit=Update

our non PGO runs also didn't see a regression.

[Bug target/109130] [13 Regression] 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU with PGO, LTO, -Ofast and -march=native

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109130

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|464.h264ref regressed by    |[13 Regression] 464.h264ref
                   |6.5% on a Neoverse-N1 CPU   |regressed by 6.5% on a
                   |with PGO, LTO, -Ofast and   |Neoverse-N1 CPU with PGO,
                   |-march=native               |LTO, -Ofast and
                   |                            |-march=native
   Target Milestone|---                         |13.0

[Bug target/109130] [13/14 Regression] 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU with PGO, LTO, -Ofast and -march=native

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109130

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.0                        |13.2

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.1 is being released, retargeting bugs to GCC 13.2.

[Bug target/109130] [13/14 Regression] 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU with PGO, LTO, -Ofast and -march=native

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109130

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.2                        |13.3

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.2 is being released, retargeting bugs to GCC 13.3.

[Bug target/109130] [13/14 Regression] 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU with PGO, LTO, -Ofast and -march=native

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109130

Jeffrey A. Law <law at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at gcc dot gnu.org
           Priority|P3                          |P2

[Bug target/109130] [13/14/15 Regression] 464.h264ref regressed by 6.5% on a Neoverse-N1 CPU with PGO, LTO, -Ofast and -march=native

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109130

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.3                        |13.4

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 13.3 is being released, retargeting bugs to GCC 13.4.