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From: Toon Moene <toon@moene.org>
To: Daniel Kraft <d@domob.eu>
Cc: Tobias Burnus <burnus@net-b.de>,
	 Jerry DeLisle <jvdelisle@verizon.net>,
	Thomas Koenig <tkoenig@netcologne.de>,
	fortran@gcc.gnu.org,  gcc-patches@gcc.gnu.org
Subject: Re: [patch, fortran] PR 40628, front-end optimization pass
Date: Tue, 20 Jul 2010 09:44:00 -0000	[thread overview]
Message-ID: <4C456FE6.7010805@moene.org> (raw)
In-Reply-To: <4C455DAD.9020509@domob.eu>

Daniel Kraft wrote:

> I just wonder if there is not yet any way to tell the middle-end that it 
> is allowed to optimize function calls away (like marking the functions 
> "pure" -- according to the c.l.f thread, this should be allowed for all 
> Fortran functions (if I understood it correctly)).

No, that's not sufficient, as I argued in my 2007 GCC Summit paper (see 
paragraph 6.3 - you also have to get rid of the temporaries that are 
allocated to hold the function results, which can be quite large (i.e., 
when eliding MATMUL calls).

It is hard to see how the middle end could do this.

-- 
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
At home: http://moene.org/~toon/; weather: http://moene.org/~hirlam/
Progress of GNU Fortran: http://gcc.gnu.org/gcc-4.5/changes.html#Fortran

  reply	other threads:[~2010-07-20  9:44 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-17 18:38 Thomas Koenig
2010-07-18  8:41 ` Daniel Kraft
2010-07-18 10:18   ` Thomas Koenig
2010-07-19 18:59     ` Toon Moene
2010-07-19 19:11       ` Thomas Koenig
2010-07-19  4:12   ` Jerry DeLisle
2010-07-19 18:21     ` Richard Henderson
2010-07-19 19:06     ` Jakub Jelinek
2010-07-19 22:31     ` Thomas Koenig
2010-07-20  1:19       ` Jerry DeLisle
2010-07-20  2:08         ` Steve Kargl
2010-07-20  2:39         ` Diego Novillo
2010-07-20  2:54           ` Jerry DeLisle
2010-07-20  8:05         ` Tobias Burnus
2010-07-20  8:21           ` Daniel Kraft
2010-07-20  9:44             ` Toon Moene [this message]
2010-07-20  9:58               ` Richard Guenther
2010-07-20 22:01                 ` Thomas Koenig
2010-07-25 15:52                   ` Tobias Burnus
2010-07-25 19:35                     ` Thomas Koenig
2010-07-25 21:15                       ` Paolo Bonzini
2010-07-26 19:24                         ` Thomas Koenig

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