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[Bug tree-optimization/50904] [4.7 regression] pessimization when -fno-protect-parens is enabled by -Ofast
- From: "ebotcazou at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sat, 19 Nov 2011 07:17:58 +0000
- Subject: [Bug tree-optimization/50904] [4.7 regression] pessimization when -fno-protect-parens is enabled by -Ofast
- Auto-submitted: auto-generated
- References: <bug-50904-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50904
--- Comment #17 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2011-11-19 07:17:58 UTC ---
> I tested on machine with -march=amdfam10, with your patch induct run time
> improves by ~5%. Other benchmarks are not affected much.
OK, thanks.
> With your patch, CPU2006 benchmark "416.gamess" fails during validation.
> Mimimal flag -O3 -fno-tree-pre -mfma4. I am trying to reduce the test case.
> Please let me know if you have any other suggestions.
I think that this should be handled at the Tree level. The missed optimization
opportunities are there, with or without -fprotect-parens.