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* [Bug gcov-profile/94410] New: 511.povray_r is 11% slower built at -O2 PGO+LTO than with GCC 9 and same options
@ 2020-03-30 17:53 jamborm at gcc dot gnu.org
  2020-03-30 17:58 ` [Bug gcov-profile/94410] " jamborm at gcc dot gnu.org
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: jamborm at gcc dot gnu.org @ 2020-03-30 17:53 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94410

            Bug ID: 94410
           Summary: 511.povray_r is 11% slower built at -O2 PGO+LTO than
                    with GCC 9 and same options
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gcov-profile
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jamborm at gcc dot gnu.org
                CC: hubicka at gcc dot gnu.org, marxin at gcc dot gnu.org
            Blocks: 26163
  Target Milestone: ---
              Host: x86_64-linux
            Target: x86_64-linux

SPEC 2017 FPrate benchmark 511.povray_r runs 11 % slower on AMD Zen2
CPU and 10% slower on Intel Cascade Lake server CPU when built with
-O2 (generic march/tuning) and both PGO and LTO with trunk (revision
26b3e568a60) than when compiled with the same options with GCC 9.

Bisecting revealed that the slowdown was introduced with:

commit 2925cad2151842daa387950e62d989090e47c91d
Author: Jan Hubicka <hubicka@ucw.cz>
Date:   Thu Oct 3 17:08:21 2019 +0200

    params.def (PARAM_INLINE_HEURISTICS_HINT_PERCENT, [...]): New.

            * params.def (PARAM_INLINE_HEURISTICS_HINT_PERCENT,
            PARAM_INLINE_HEURISTICS_HINT_PERCENT_O2): New.
            * doc/invoke.texi (inline-heuristics-hint-percent,
            inline-heuristics-hint-percent-O2): Document.
            * tree-inline.c (inline_insns_single, inline_insns_auto): Add new
            hint attribute.
            (can_inline_edge_by_limits_p): Use it.

    From-SVN: r276516

The revision just before it was even 9% and 7% faster than GCC 9 on
AMD and Intel respectively.


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)

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Bug gcov-profile/94410] 511.povray_r is 11% slower built at -O2 PGO+LTO than with GCC 9 and same options
  2020-03-30 17:53 [Bug gcov-profile/94410] New: 511.povray_r is 11% slower built at -O2 PGO+LTO than with GCC 9 and same options jamborm at gcc dot gnu.org
@ 2020-03-30 17:58 ` jamborm at gcc dot gnu.org
  2020-03-30 20:17 ` jamborm at gcc dot gnu.org
  2023-01-18 17:52 ` jamborm at gcc dot gnu.org
  2 siblings, 0 replies; 4+ messages in thread
From: jamborm at gcc dot gnu.org @ 2020-03-30 17:58 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94410

Martin Jambor <jamborm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=94360

--- Comment #1 from Martin Jambor <jamborm at gcc dot gnu.org> ---
PR94360 is another O2 PGO+LTO bug where the commit caused a slowdown.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Bug gcov-profile/94410] 511.povray_r is 11% slower built at -O2 PGO+LTO than with GCC 9 and same options
  2020-03-30 17:53 [Bug gcov-profile/94410] New: 511.povray_r is 11% slower built at -O2 PGO+LTO than with GCC 9 and same options jamborm at gcc dot gnu.org
  2020-03-30 17:58 ` [Bug gcov-profile/94410] " jamborm at gcc dot gnu.org
@ 2020-03-30 20:17 ` jamborm at gcc dot gnu.org
  2023-01-18 17:52 ` jamborm at gcc dot gnu.org
  2 siblings, 0 replies; 4+ messages in thread
From: jamborm at gcc dot gnu.org @ 2020-03-30 20:17 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94410

--- Comment #2 from Martin Jambor <jamborm at gcc dot gnu.org> ---
For the record, SPEC 2006 453.povray is similarly affected, the commit
makes it run 26% slower.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Bug gcov-profile/94410] 511.povray_r is 11% slower built at -O2 PGO+LTO than with GCC 9 and same options
  2020-03-30 17:53 [Bug gcov-profile/94410] New: 511.povray_r is 11% slower built at -O2 PGO+LTO than with GCC 9 and same options jamborm at gcc dot gnu.org
  2020-03-30 17:58 ` [Bug gcov-profile/94410] " jamborm at gcc dot gnu.org
  2020-03-30 20:17 ` jamborm at gcc dot gnu.org
@ 2023-01-18 17:52 ` jamborm at gcc dot gnu.org
  2 siblings, 0 replies; 4+ messages in thread
From: jamborm at gcc dot gnu.org @ 2023-01-18 17:52 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94410

--- Comment #3 from Martin Jambor <jamborm at gcc dot gnu.org> ---
This is still the case, as can be seen on LNT (GCC 9 is the dot in the left
bottom corner):

https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=690.467.0&plot.1=745.467.0&plot.2=777.467.0&plot.3=687.467.0&

^ permalink raw reply	[flat|nested] 4+ messages in thread

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2020-03-30 17:53 [Bug gcov-profile/94410] New: 511.povray_r is 11% slower built at -O2 PGO+LTO than with GCC 9 and same options jamborm at gcc dot gnu.org
2020-03-30 17:58 ` [Bug gcov-profile/94410] " jamborm at gcc dot gnu.org
2020-03-30 20:17 ` jamborm at gcc dot gnu.org
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