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From: "law at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/112545] [14 Regression] Size regression when using -Os starting with r14-569-g21e2ef2dc25
Date: Sat, 09 Mar 2024 05:04:46 +0000	[thread overview]
Message-ID: <bug-112545-4-BqJ0OogEBg@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-112545-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112545

--- Comment #2 from Jeffrey A. Law <law at gcc dot gnu.org> ---
This looks like a missed case for singletons.

  _1 = d.9_28 <= 0;
  _2 = (signed short) _1;
  _3 = (signed short) d.9_28;
  c.a = 0;
  if (_2 == _3)
    goto <bb 4>; [0.00%]
  else
    goto <bb 5>; [100.00%]


Back substituting the condition is:

(d.9_28 <= 0) == d.9_28

d.9_28 <= 0 has a range [0,1]

The only value that can make that expression true is if d.9_28 has the value 0.

  parent reply	other threads:[~2024-03-09  5:04 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-15 12:50 [Bug tree-optimization/112545] New: " theodort at inf dot ethz.ch
2023-11-15 13:43 ` [Bug tree-optimization/112545] " rguenth at gcc dot gnu.org
2023-11-15 16:26 ` pinskia at gcc dot gnu.org
2024-03-07 21:01 ` law at gcc dot gnu.org
2024-03-09  5:04 ` law at gcc dot gnu.org [this message]
2024-05-07  7:42 ` [Bug tree-optimization/112545] [14/15 " rguenth at gcc dot gnu.org

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