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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/110080] [13/14 Regression] Missed Dead Code Elimination at -Os when using __builtin_unreachable since r13-6945-g429a7a88438
Date: Mon, 21 Aug 2023 23:20:55 +0000	[thread overview]
Message-ID: <bug-110080-4-yrWfdWYmGT@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-110080-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110080

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
  a.0_1 = aD.2830;
  # RANGE [irange] unsigned int [0, 255] MASK 0xff VALUE 0x0
  _2 = (unsigned intD.9) a.0_1;
  # RANGE [irange] unsigned char [0, 0][4, 4] MASK 0x4 VALUE 0x0
  _6 = a.0_1 & 4;
  # RANGE [irange] int [0, 0][4, 4] MASK 0x4 VALUE 0x0
  _3 = (intD.6) _6;

Those ranges should have been:
a.0_1 [131,131]
_2 [131,131]
_6 [0,0]
_3 [0,0]

Like we got from the (not) unreachable branch:
=========== BB 4 ============
Imports: a.0_1  _3  
Exports: a.0_1  _3  _6  
a.0_1   [irange] unsigned char [131, 131]
_3      [irange] int [0, 0] MASK 0x4 VALUE 0x0


The store to e was not 131 because it was before the unreachable though:
  e = _3;
  if (a.0_1 != 131)
    goto <bb 3>; [0.00%]
  else
    goto <bb 4>; [100.00%]

  <bb 3> [count: 0]:
  __builtin_unreachable ();

  parent reply	other threads:[~2023-08-21 23:20 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-01 13:54 [Bug tree-optimization/110080] New: " theodort at inf dot ethz.ch
2023-06-01 14:02 ` [Bug tree-optimization/110080] " theodort at inf dot ethz.ch
2023-06-02  7:53 ` rguenth at gcc dot gnu.org
2023-07-27  9:26 ` rguenth at gcc dot gnu.org
2023-08-21 23:20 ` pinskia at gcc dot gnu.org [this message]
2023-08-21 23:21 ` pinskia at gcc dot gnu.org
2023-09-19 14:30 ` cvs-commit at gcc dot gnu.org
2023-09-19 15:03 ` amacleod at redhat dot com

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