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 A70D3382EA07; Fri, 30 Jun 2023 22:29:47 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A70D3382EA07
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1688164187;
	bh=GV4K5gcn7bhCNxLCeJuwcsyD/L5UAzZ9QVywseP/0Qs=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=LW/YO5VK9K699t73pYYU3ePzPFc302ELOqeay783jD6W3onPIl6tMHnjpc0YIpg7D
	 ShLbLDuE6nSe7HEXcqo3l5PiQOkSpt4vVYw8EDd5DJVBUh3nPbAincYeiOlfRXEZW5
	 y0QbuTJxHg8u/26mPQdL5jP2z+sB4E0t6ChB/e+0=
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/110503] [13/14 Regression] Dead Code
 Elimination Regression at -O3 since  r13-322-g7f04b0d786e
Date: Fri, 30 Jun 2023 22:29:47 +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: normal
X-Bugzilla-Who: pinskia at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 13.2
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-110503-4-5M8KNBvDBN@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-110503-4@http.gcc.gnu.org/bugzilla/>
References: <bug-110503-4@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=3D110503

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
>=20
> Oh and had:
>   # RANGE [irange] int [-128, 127]
>   _10 =3D (intD.6) _9;
>   # RANGE [irange] int [0, 1] NONZERO 0x1
>   _11 =3D 1 % _10;
>=20
> I wonder if we could optimize `1 % b` into just `b !=3D 1` (since 1 % 0 is
> undefined) which will further reduce things here.

That does not change the size of the loop though and we are still left with:
  size:   1 _10 =3D _9 =3D=3D 1;
  size:   0 _11 =3D (unsigned int) _10;
  size:   1 _12 =3D -_11;
  size:   2 if (_12 > 2)

But at least now we just need to optimize the above to just `if (_9 =3D=3D =
1)`

Something like:
(simplify
 (gt (negative zero_one_value@0) INTEGER_CST@1)
 (if (wi::to_wide (@1) >=3D 1 && TYPE_UNSIGNED (TREE_TYPE (@1)))
  (ne @0 { build_zero_cst (TREE_TYPE (@1)); } )
  (if (wi::to_wide (@1) >=3D 0 && !TYPE_UNSIGNED (TREE_TYPE (@1)))
   (eq @0 { build_zero_cst (TREE_TYPE (@1)); } )
  )
 )
)

But I get the feeling this should be done in VRP instead of match ...=