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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/37242] missed FRE opportunity because of signedness of addition
Date: Thu, 28 Aug 2008 08:47:00 -0000	[thread overview]
Message-ID: <20080828084546.12245.qmail@sourceware.org> (raw)
In-Reply-To: <bug-37242-7849@http.gcc.gnu.org/bugzilla/>



------- Comment #16 from rguenther at suse dot de  2008-08-28 08:45 -------
Subject: Re:  missed FRE opportunity because of
 signedness of addition

On Thu, 28 Aug 2008, bonzini at gnu dot org wrote:

> ------- Comment #15 from bonzini at gnu dot org  2008-08-28 08:42 -------
> I think that PRE does not try to simplify expressions that it inserts.

Correct.  PRE does minimal expression simplification during PHI 
translation, but that's it.  Note that gimple expressions itself
never simplify apart from constant folding, the simplify_*_expression
routines in SCCVN instead combine multiple expressions.

Is the optimization the second PRE run does a full redundancy removal
or a new partial redundancy?

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37242


  parent reply	other threads:[~2008-08-28  8:47 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-26 11:55 [Bug tree-optimization/37242] New: missed load PRE-like opportunity bonzini at gnu dot org
2008-08-26 11:57 ` [Bug tree-optimization/37242] " bonzini at gnu dot org
2008-08-26 12:03 ` [Bug tree-optimization/37242] missed FRE opportunity bonzini at gnu dot org
2008-08-26 21:17 ` [Bug tree-optimization/37242] missed FRE opportunity because of signedness of addition pinskia at gcc dot gnu dot org
2008-08-27  6:42 ` bonzini at gnu dot org
2008-08-27  7:16 ` bonzini at gnu dot org
2008-08-27  7:16 ` bonzini at gnu dot org
2008-08-27  9:42 ` rguenther at suse dot de
2008-08-27 17:51 ` bonzini at gnu dot org
2008-08-27 19:13 ` rguenther at suse dot de
2008-08-27 19:55 ` bonzini at gnu dot org
2008-08-27 20:18 ` rguenther at suse dot de
2008-08-28  6:10 ` bonzini at gnu dot org
2008-08-28  6:18 ` bonzini at gnu dot org
2008-08-28  8:03 ` rguenther at suse dot de
2008-08-28  8:43 ` bonzini at gnu dot org
2008-08-28  8:47 ` rguenther at suse dot de [this message]
2008-08-28  8:58 ` bonzini at gnu dot org
2008-08-28  8:59 ` bonzini at gnu dot org
2008-08-29  4:39 ` pinskia at gcc dot gnu dot org
     [not found] <bug-37242-4@http.gcc.gnu.org/bugzilla/>
2011-04-27 17:57 ` matt at use dot net
2011-04-28  9:53 ` rguenth at gcc dot gnu.org
2012-04-18 22:51 ` pinskia at gcc dot gnu.org
2012-06-29  0:20 ` matt at use dot net

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