https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90364
Martin Jambor <jamborm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2019-05-06 00:00:00 |2020-3-30
Summary|521.wrf_r is 9.5 % slower |521.wrf_r is 8-17% slower
|with PGO on Zen CPUs at |with PGO at -Ofast and
|-Ofast and native |native march/mtune
|march/mtune |
--- Comment #9 from Martin Jambor <jamborm at gcc dot gnu.org> ---
The problem still persists accross the board, causing:
- 17% regression against non-PGO on AMD Zen2 CPU,
- 8% regression against non-PGO on AMD Zen1 CPU, and
- 12% regression against non-PGO on Intel Cascade Lake server CPU.
All of the above is at -Ofast -march=native, by the way, at just -O2
(and generic -march) PGO actually helps by 25-27% on all three
systems, so I would double check before blaming specinvoke (though of
course it might be the culprit).
