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Re: -funsafe-loop-optimizations
- From: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- To: Mark Mitchell <mark at codesourcery dot com>
- Cc: David Edelsohn <dje at watson dot ibm dot com>,Richard Henderson <rth at redhat dot com>,Daniel Berlin <dberlin at dberlin dot org>, gcc at gcc dot gnu dot org
- Date: Tue, 4 Jan 2005 23:30:23 +0100
- Subject: Re: -funsafe-loop-optimizations
- References: <20041231211409.GA22814@atrey.karlin.mff.cuni.cz> <Pine.LNX.4.60.0412311649170.6844@dberlin.org> <20041231232501.GA16663@redhat.com> <200501010543.j015h3D33264@makai.watson.ibm.com> <41DAE4DF.5060903@codesourcery.com>
Hello,
> David Edelsohn wrote:
>
> > While we discuss whether this should be the default or enabled at
> >any optimization level, can we agree that users should be able to assert
> >with a commandline option that they want less strict induction variable
> >semantics? I hope that we can move forward with an option to address
> >these performance regressions and allow users to request this optimzation
> >when they *do* want it, along the lines of the draft patch.
>
> I would certainly agree. I think the first thing to do is to get a
> patch that implements the semantics we want, in the aggressive mode;
> then, we can decide whether we want it to be the default at some
> optimization level or not.
the patch (not final version, but usable for testing) is already
available.
http://gcc.gnu.org/ml/gcc/2005-01/msg00059.html
Zdenek