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[Bug middle-end/53338] [4.8 Regression] Unaligned store generated for aligned data
- From: "dominiq at lps dot ens.fr" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 14 May 2012 09:21:41 +0000
- Subject: [Bug middle-end/53338] [4.8 Regression] Unaligned store generated for aligned data
- Auto-submitted: auto-generated
- References: <bug-53338-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53338
--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> 2012-05-14 09:21:41 UTC ---
> 20% runtime regression in rnflow [1] happened in this timeframe, perhaps it
> could be attributed to the patch, mentioned in Comment #2.
This slowdown is caused by revision 187092 in the proc cptrf2. A further
slowdown (~5%) is caused by revision 187340 in the proc evlrnf. While tracking
these slowdowns I also noticed that for any revision compiling rnflow.f90 is
slower if I use -O3 only compared to the use of -O2 only (cptrf2 seems the
culprit). The best timings I get are when I compile evlrnf with '-O3
-ffast-math -funroll-loops'.
I am planning to open some PRs about these findings which do not seem related
to this one (unless someone beat me).