https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127644
Bug ID: 127644
Summary: 5-9% slowdowns of SPEC 2006 hmmer since
r17-4622-gbbf9808d787eac
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: jmelcr at gcc dot gnu.org
CC: rguenth at gcc dot gnu.org
Blocks: 26163
Target Milestone: ---
Host: x86_64-suse-linux
Target: x86_64-suse-linux
Build: x86_64-suse-linux
I am seeing numerous SPEC 2006 hmmer slowdowns on various targets:
8% on znver2 with -O2 -flto=128 -g:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=292.180.0
6% on znver3 with -O2 -flto=128 -g:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=469.180.0
6% on znver4 with -O2 -g -flto=128 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3
-fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables
-fstack-clash-protection:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=1100.180.0
7% on znver4 with -O2 -flto=128 -g:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=956.180.0
9% on znver5 with -O2 -flto=128 -g:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=1238.180.0
6% on Intel Ice Lake (3rd generation Xeon) with -O2 -g:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=784.180.0
6% on Intel Ice Lake (3rd generation Xeon) with -O2 -g -flto=128:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=799.180.0
I reproduced the first two slowdowns, both bisect to r17-4622-gbbf9808d787eac,
I assume the rest are the same:
commit bbf9808d787eacf4464f2298d2f4265855b006bf
Author: Richard Biener <[email protected]>
Date: Wed Sep 23 11:04:39 2026 +0200
account for SSE to integer move cost for vec_to_scalar
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26163
[Bug 26163] [meta-bug] missed optimization in SPEC (2026, 2k17, 2k and 2k6 and
95)
