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Re: [RFC] Enabling loop unrolls at -O3?
- From: Andrew Pinski <pinskia at physics dot uc dot edu>
- To: rasky at develer dot com (Giovanni Bajo)
- Cc: richard dot guenther at gmail dot com (Richard Guenther), stevenb at suse dot de (Steven Bosscher), gcc at gcc dot gnu dot org, dewar at adacore dot com (Robert Dewar)
- Date: Sat, 5 Nov 2005 14:11:10 -0500 (EST)
- Subject: Re: [RFC] Enabling loop unrolls at -O3?
>
> Richard Guenther <richard.guenther@gmail.com> wrote:
>
> >> My feeling is that -funroll-loops is almost always an improvement. It
> might
> >> be false sometimes, but this can be said of many optimization passes.
> >
> > Can you back up this feeling with numbers? SPEC -O2
> vs. -O2 -funroll-loops
> > and/or -O3 vs. -O3 -funroll-loops would do it.
>
>
> I don't have access to SPEC, sorry. I believe you do, though?
The last time this was proposed, -funroll-loops caused a couple of
wrong-code in SPEC but nobody had the time to look into them.
Note I proposed it and I don't think it is correct at this late
stage into 4.1's release and it is not a bug fix either.
-- Pinski