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Date: Fri, 10 Aug 2012 14:08:14 -0400
From: Rich Felker <dalias@...ifal.cx>
To: musl@...ts.openwall.com
Subject: Re: crypt_blowfish integration, optimization

On Fri, Aug 10, 2012 at 09:18:03PM +0400, Solar Designer wrote:
> > Not sure. I've found -Q --help=optimizers completely unreliable in the
> > past though. It only reports minimal differences between -Os, -O2, and
> > -O3, and trying to start with -O3 and reproduce -Os by just changing
> > the options that are different does not give effects even remotely
> > similar to -Os.
> 
> Frankly, this matches my experience.  OK, -Q --help=optimizers is
> unreliable.  But is -O3 supposed to include -funroll-loops now?  Does
> it?  Or did you get loop unrolling done for some other reason?  I think
> this needs to be understood by us.

Yes, -O3 includes -funroll-loops, which is intelligent about choosing
which loops to unroll. There's -funroll-all-loops that's much more
aggressive and not included in any -O level by default.

Rich

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