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Date: Wed, 31 Oct 2012 12:45:00 -0000
From: Richard Biener <rguenther@suse.de>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Jan Hubicka <hubicka@ucw.cz>, gcc-patches@gcc.gnu.org
Subject: Re: Non-dominating loop bounds in tree-ssa-loop-niter 3/4
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On Wed, 31 Oct 2012, Jakub Jelinek wrote:

> On Wed, Oct 31, 2012 at 01:30:02PM +0100, Richard Biener wrote:
> > On Wed, 31 Oct 2012, Jan Hubicka wrote:
> > > > unroll you mean.  Because unrolling mutates the CFG too much.
> > > > Well - it was just a starting point, populating -Og with as little
> > > > as possible and 100% profitable transforms (in both debug and speed
> > > > metric).  In late opts we only do (early opt queue is shared):
> > > 
> > > Well, and what about early cunrolli?
> > 
> > It's not there (and I would disable it for -Og).
> 
> Generally, most of the loop transforms are undesirable for -Og.

Maybe with the exception of un-looping once rolling loops.  But
yes, even loop header copying is undesirable in general.

Richard.