https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127432
Bug ID: 127432
Summary: [17 Regression] 17% slowdown of calculix on aarch64
since r17-4170-g81d25063773b48
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jmelcr at gcc dot gnu.org
CC: rdapp at gcc dot gnu.org
Blocks: 26163
Target Milestone: ---
Host: aarch64-suse-linux
Target: aarch64-suse-linux
Build: aarch64-suse-linux
I am seeing a 17% exec time slowdown of SPEC 2006 calculix with -Ofast
-march=native -g PGO on aarch64 (Neoverse N1):
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=578.170.0
This is a regression against GCC 16:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=1066.170.0&plot.1=1236.170.0&plot.2=1528.170.0&plot.3=578.170.0&;
The slowdown bisects to r17-4170-g81d25063773b48:
commit 81d25063773b48a163b0198aa5ed4a5468142e05
Author: Robin Dapp <[email protected]>
Date: Mon Aug 31 14:42:18 2026 +0200
aarch64: Set REGMODE_NATURAL_SIZE for advsimd vectors.
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)
