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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/19832] don't remove an if when we know the value is the same as with the if (subtraction)
Date: Mon, 06 Aug 2012 11:41:00 -0000	[thread overview]
Message-ID: <bug-19832-4-24llFHioS1@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-19832-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19832

--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-08-06 11:41:27 UTC ---
There is no straight-forward place to handle transform of

  <bb 2>:
  if (i_2(D) != j_3(D))
    goto <bb 3>;
  else
    goto <bb 4>;

  <bb 3>:
  D.1715_4 = i_2(D) - j_3(D);

  <bb 4>:
  # D.1715_1 = PHI <D.1715_4(3), 0(2)>

to

  <bb 2>:

  <bb 3>:
  D.1715_4 = i_2(D) - j_3(D);

  <bb 4>:
  D.1715_1 = D.1715_4;

but it eventually feels like a phi-opt transform.


  parent reply	other threads:[~2012-08-06 11:41 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-19832-4@http.gcc.gnu.org/bugzilla/>
2011-08-13  1:39 ` jimis at gmx dot net
2011-08-13  2:21 ` jimis at gmx dot net
2012-08-06 11:41 ` rguenth at gcc dot gnu.org [this message]
2023-05-06 21:15 ` pinskia at gcc dot gnu.org
2023-05-06 23:12 ` pinskia at gcc dot gnu.org
2023-05-06 23:13 ` pinskia at gcc dot gnu.org
2023-08-31  1:03 ` pinskia at gcc dot gnu.org
2023-08-31  4:48 ` pinskia at gcc dot gnu.org
2023-08-31 18:03 ` pinskia at gcc dot gnu.org
2023-09-01  6:58 ` cvs-commit at gcc dot gnu.org
2023-09-01  6:58 ` pinskia at gcc dot gnu.org
2023-09-01 12:23 ` cvs-commit at gcc dot gnu.org
2023-12-25  4:02 ` cvs-commit at gcc dot gnu.org
2005-02-09  7:41 [Bug c/19832] New: Missed optimisation christophe dot jaillet at wanadoo dot fr
2005-02-09  7:46 ` [Bug tree-optimization/19832] don't remove an if when we know the value is the same as with the if (subtraction) pinskia at gcc dot gnu dot org

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