https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101296
Bug ID: 101296
Summary: Addition of x86 addsub SLP patterned slowed down
433.milc by 12% on znver2 with -Ofast -flto
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jamborm at gcc dot gnu.org
CC: rguenth at gcc dot gnu.org
Target Milestone: ---
Host: x86_64-linux
Target: x86_64-linux
Commit g:7a6c31f0f84 (Add x86 addsub SLP pattern) has slowed down
433.milc from SPECFP 2006 by 12% on a znver2 based machine when
compiled with -Ofast -flto -march=native.
Note however that the master branch has afterwards recovered some of
these losses and today's bc8f0ed7042 is only 6% slower than what it
was before the addsub addition. Nevertheless, this effect of this
particular change may be worth looking at.
LNT tracking graph is available for example here:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=289.70.0
