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 <[email protected]>
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)
