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From: "sebastian dot pop at cri dot ensmp dot fr" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/23821] [4.0/4.1/4.2 Regression] DOM and VRP creating harder to optimize code
Date: Mon, 13 Feb 2006 08:45:00 -0000	[thread overview]
Message-ID: <20060213084515.6532.qmail@sourceware.org> (raw)
In-Reply-To: <bug-23821-5077@http.gcc.gnu.org/bugzilla/>



------- Comment #8 from sebastian dot pop at cri dot ensmp dot fr  2006-02-13 08:45 -------
Subject: Re:  [4.0/4.1/4.2 Regression] DOM and VRP creating harder to optimize
code

This case reminds me the peeled chrec unification that I had to
disable on autovect branch (I probably have to run the transformation
as a stand alone pass outside the analyzer for not disturbing the user
passes).  In that case we're looking at a code like

loop
  x = phi (0, a)
  a = phi (1, a + 1)
endloop

such that a simple transformation can make "x" a simple iv.  This case
is also quite important, as it occurs about 300 times during a bootstrap.

Now for the current problem, we could run a pass just after loop_init
for cleaning all these constructs.  As suggested, we would have to
build an equivalence relation either like VRP, or on demand.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23821


  parent reply	other threads:[~2006-02-13  8:45 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-23821-5077@http.gcc.gnu.org/bugzilla/>
2005-10-16 22:10 ` [Bug tree-optimization/23821] [4.0/4.1 " pinskia at gcc dot gnu dot org
2005-10-31  5:42 ` mmitchel at gcc dot gnu dot org
2005-11-13 16:17 ` steven at gcc dot gnu dot org
2005-11-14  9:16 ` rakdver at gcc dot gnu dot org
2006-02-09 23:05 ` [Bug tree-optimization/23821] [4.0/4.1/4.2 " steven at gcc dot gnu dot org
2006-02-09 23:52 ` rakdver at gcc dot gnu dot org
2006-02-13  8:45 ` sebastian dot pop at cri dot ensmp dot fr [this message]
2006-02-24  0:26 ` mmitchel at gcc dot gnu dot org
2006-05-25  2:35 ` mmitchel at gcc dot gnu dot org
2007-02-14  9:11 ` [Bug tree-optimization/23821] [4.0/4.1/4.2/4.3 " mmitchel at gcc dot gnu dot org
2007-10-19 21:54 ` spop at gcc dot gnu dot org
2007-12-16 23:17 ` steven at gcc dot gnu dot org
2008-01-10  1:21 ` spop at gcc dot gnu dot org
2008-01-12  0:12 ` spop at gcc dot gnu dot org
2008-01-12  2:33 ` sebpop at gmail dot com
2008-01-12 12:39 ` rguenth at gcc dot gnu dot org
2008-01-12 12:39 ` pinskia at gmail dot com
2008-01-12 12:43 ` rguenth at gcc dot gnu dot org
2008-01-12 12:45 ` pinskia at gcc dot gnu dot org
2008-07-04 20:03 ` [Bug tree-optimization/23821] [4.2/4.3/4.4 " jsm28 at gcc dot gnu dot org
2009-03-31 18:55 ` [Bug tree-optimization/23821] [4.3/4.4/4.5 " jsm28 at gcc dot gnu dot org
2009-07-22 16:27 ` spop at gcc dot gnu dot org
2009-07-22 19:33 ` rguenth at gcc dot gnu dot org
2009-08-04 12:32 ` rguenth at gcc dot gnu dot org
2009-09-23 15:23 ` rguenth at gcc dot gnu dot org
2009-09-25 14:27 ` rahul at icerasemi dot com
2009-09-25 14:40 ` rguenth at gcc dot gnu dot org
2009-09-25 14:59 ` rguenth at gcc dot gnu dot org
2009-09-25 17:10 ` rahul at icerasemi dot com
2009-09-28 11:18 ` rguenth at gcc dot gnu dot org
2009-10-05 13:18 ` rguenth at gcc dot gnu dot org
2009-10-05 13:19 ` [Bug tree-optimization/23821] [4.3/4.4 " rguenth at gcc dot gnu dot org

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