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[Bug tree-optimization/50905] Gcc4.6.x's -ftree-parallelize-loops is effective only when using "-O2/-O3 -ffast-math"
- From: "pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 28 Oct 2011 19:45:18 +0000
- Subject: [Bug tree-optimization/50905] Gcc4.6.x's -ftree-parallelize-loops is effective only when using "-O2/-O3 -ffast-math"
- Auto-submitted: auto-generated
- References: <bug-50905-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50905
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-10-28 19:45:18 UTC ---
>Am I right?
Yes but the reason comes down to fp math is not associative which means it is
impossible to do reductions with fp math unless you have -ffast-math (or really
-fassociative-math) turned on.