From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id B663B385771C; Wed, 11 Oct 2023 14:00:44 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org B663B385771C
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1697032844;
	bh=B0V1r37D5EeC2yHBxsUDaCC3ejgz3UicpYB1Q8QGpIs=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=pkn80925uvtRzCdNlfe9ae5TEc1GPiQQMza6vOaA6DwM3pdfLCXS0DUpNgJ70j7q1
	 Q3MvRIZl1K4Ppsj1HJ/eEvdkQJ1h8O0f+mwGq0bQi92lte2bOCkUy3GbZVHt6NcKWF
	 kW4gnQ7n14V0h8aSCzmFRXaNF0fLQIJUVOQwT79E=
From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/111766] Missed optimization with
 __builtin_unreachable and ands
Date: Wed, 11 Oct 2023 14:00:44 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: enhancement
X-Bugzilla-Who: amacleod at redhat dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-111766-4-y3PqvNeUKR@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-111766-4@http.gcc.gnu.org/bugzilla/>
References: <bug-111766-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111766

--- Comment #1 from Andrew Macleod <amacleod at redhat dot com> ---


Imports: bb_3(D)
Exports: _2  bb_3(D)
         _2 : bb_3(D)(I)
bb_3(D) [irange] int [0, 3] MASK 0x3 VALUE 0x0
    <bb 4> :
    _2 =3D bb_3(D) & 1;
    if (_2 =3D=3D 0)
      goto <bb 5>; [INV]
    else
      goto <bb 6>; [INV]

_2 : [irange] int [0, 1] MASK 0x1 VALUE 0x0
4->5  (T) _2 :  [irange] int [0, 0] MASK 0x1 VALUE 0x0
4->5  (T) bb_3(D) :     [irange] int [0, 0][2, 2] MASK 0x2 VALUE 0x0
4->6  (F) _2 :  [irange] int [1, 1] MASK 0x1 VALUE 0x0
4->6  (F) bb_3(D) :     [irange] int [1, 3] MASK 0x2 VALUE 0x1

Looks like its just a lack of completeness in
operator_bitwise_and::op1_range().
on the edge from 4->6 ranger knows _2 is [1,1], but when op1_range solves f=
or
  _2 =3D bb_3 & 1
we have=20=20
  [1,1] =3D  int [0, 3] MASK 0x3 VALUE 0x0    &   1
and it produces int [1, 3] rather than [1,1][3,3]=