From: Andrew Pinski <pinskia@gmail.com>
To: Tom de Vries <tom@codesourcery.com>
Cc: gcc-patches@gcc.gnu.org, Bernd Schmidt <bernds@codesourcery.com>
Subject: Re: new sign/zero extension elimination pass
Date: Thu, 28 Oct 2010 22:58:00 -0000 [thread overview]
Message-ID: <AANLkTi=7QkZr_PC2EDVoCvvqK1xoBM24JGNMMVRO9sJB@mail.gmail.com> (raw)
In-Reply-To: <4CC9CF40.2020904@codesourcery.com>
On Thu, Oct 28, 2010 at 12:30 PM, Tom de Vries <tom@codesourcery.com> wrote:
> I agreed with Paolo in http://gcc.gnu.org/ml/gcc-patches/2010-10/msg01897.html
> that for the example with which I submitted the pass initially, it would make
> sense to handle it in fwprop. However, I also think that for the example
> mentioned in http://gcc.gnu.org/ml/gcc-patches/2010-10/msg01796.html, that
> wouldn't work, so we still need the new pass.
Well when I look at the tree dumps I see:
(short unsigned int) ((int) (*D.1255)[1] + (int) (*D.1255)[0])
So we should be optimizing this at the tree level such that we don't
see extra sign extends there. We would optimize it such that it looks
like:
(short unsigned int)(*D.1255)[1] + (short unsigned int)(*D.1255)[0]
I think we need a tree combiner for that and fold to do the folding.
See PR 14844 for another case of the problem.
-- Pinski
next prev parent reply other threads:[~2010-10-28 19:41 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-18 15:54 Tom de Vries
2010-10-18 16:03 ` Andrew Pinski
2010-10-18 16:59 ` Richard Guenther
2010-10-21 10:06 ` Tom de Vries
2010-10-21 10:44 ` Paolo Bonzini
2010-10-21 11:00 ` Paolo Bonzini
2010-10-21 17:21 ` Paolo Bonzini
2010-10-22 9:05 ` Tom de Vries
2010-10-22 9:24 ` Paolo Bonzini
2010-10-22 9:15 ` Eric Botcazou
2010-10-28 20:45 ` Tom de Vries
2010-10-29 2:11 ` Paolo Bonzini
2010-10-29 2:42 ` Paolo Bonzini
2010-10-31 19:30 ` Tom de Vries
2010-10-31 20:58 ` Joseph S. Myers
2010-10-31 21:11 ` Paolo Bonzini
2010-11-03 18:49 ` Eric Botcazou
2010-10-29 1:04 ` Paolo Bonzini
2010-10-29 1:33 ` Paolo Bonzini
2010-11-03 18:50 ` Eric Botcazou
2010-11-08 21:29 ` Tom de Vries
2010-11-08 22:11 ` Paolo Bonzini
2010-11-12 8:29 ` Tom de Vries
2010-11-13 10:41 ` Eric Botcazou
2012-07-11 10:31 ` Tom de Vries
2012-07-11 11:42 ` Jakub Jelinek
2012-07-11 13:01 ` Tom de Vries
2012-07-12 1:52 ` Kenneth Zadeck
[not found] ` <4FFE2ADF.2060806@naturalbridge.com>
[not found] ` <4FFE9346.2070806@mentor.com>
2012-07-12 9:21 ` Tom de Vries
2012-07-12 12:05 ` Kenneth Zadeck
2012-07-13 7:54 ` Tom de Vries
2012-07-13 11:39 ` Kenneth Zadeck
2012-07-13 12:58 ` Tom de Vries
2012-07-17 15:17 ` Kenneth Zadeck
2012-07-20 18:41 ` Tom de Vries
2012-08-20 13:40 ` Tom de Vries
2010-10-28 20:55 ` Andrew Pinski
2010-10-28 21:00 ` Andrew Pinski
2010-10-28 21:12 ` Tom de Vries
2010-10-28 22:58 ` Andrew Pinski [this message]
2010-10-29 15:06 ` Tom de Vries
2010-10-29 0:34 ` Paolo Bonzini
2010-11-08 21:32 ` Andrew Pinski
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