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[Bug rtl-optimization/31360] [4.3 Regression] rtl loop invariant is broken
- From: "rakdver at atrey dot karlin dot mff dot cuni dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 26 Mar 2007 17:18:17 -0000
- Subject: [Bug rtl-optimization/31360] [4.3 Regression] rtl loop invariant is broken
- References: <bug-31360-6528@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #6 from rakdver at atrey dot karlin dot mff dot cuni dot cz 2007-03-26 18:18 -------
Subject: Re: [4.3 Regression] rtl loop invariant is broken
> > I would agree, if we had RA capable of that (which I am not quite sure
> > whether we do or not, although this seems simple enough), or better,
> > RA doing better job under high register pressure.
>
> Then how do you explain why loop.c pulled this out of the loop but the new rtl
> loop invariant does not? I don't see why we should care about register
> pressure except inside the RA. Every other compiler does it that way, plus
> they work better than GCC.
some citation (on both claims)? Of course, it is straightforward to
remove the register pressure checks from the optimizers, so if you want,
you can experiment with that.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31360