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[Bug middle-end/77484] [6/7 Regression] Static branch predictor causes ~6-8% regression of SPEC2000 GAP
- From: "hubicka at ucw dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 16 Jan 2017 23:34:26 +0000
- Subject: [Bug middle-end/77484] [6/7 Regression] Static branch predictor causes ~6-8% regression of SPEC2000 GAP
- Auto-submitted: auto-generated
- References: <bug-77484-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77484
--- Comment #28 from Jan Hubicka <hubicka at ucw dot cz> ---
> On SPEC2000 the latest changes look good, compared to the old predictor gap
> improved by 10% and INT/FP by 0.8%/0.6%. I'll run SPEC2006 tonight.
It is rather surprising you are seeing such large changes for one branch
predictor
change. Is most of it really comming just from the bb-reorder changes? On x86
the
effect is mostly within noise and on Itanium Gap improve by 2-3%.
It may be interesting to experiment with reorderin and prediction more on this
target.
Honza