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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/94892] (x >> 31) + 1 not getting narrowed to compare
Date: Wed, 15 Dec 2021 00:31:12 +0000	[thread overview]
Message-ID: <bug-94892-4-gEKNp4SfDt@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-94892-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94892

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Two things we should simplify:
  _4 = _3 >> 31;
  _4 != -1

Into:
  _3 >= 0 (if _3 is signed, otherwise false)

(this will solve f0)


And:
  _4 = x_3(D) >> 31;
  _7 = -x_3(D);
  _8 = (unsigned int) _7;
  _9 = _8 >> 31;
  _10 = (int) _9;
  _11 = _4 | _10;

Into:
_4 = x_3(D) >> 31; // keep around
_t = _4 | 1;
_11 = x != 0 ? _t : 0;

  parent reply	other threads:[~2021-12-15  0:31 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30 17:25 [Bug tree-optimization/94892] New: " gabravier at gmail dot com
2020-04-30 18:34 ` [Bug target/94892] " pinskia at gcc dot gnu.org
2020-04-30 19:32 ` gabravier at gmail dot com
2020-05-01 19:28 ` harald at gigawatt dot nl
2020-08-10  0:19 ` gabravier at gmail dot com
2021-12-15  0:23 ` [Bug tree-optimization/94892] " pinskia at gcc dot gnu.org
2021-12-15  0:31 ` pinskia at gcc dot gnu.org [this message]
2023-05-28 23:15 ` pinskia at gcc dot gnu.org

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