[Bug tree-optimization/50904] [4.7 regression] pessimization when -fno-protect-parens is enabled by -Ofast

[ebotcazou at gcc dot gnu.org]

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.