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 CFA1B388302E; Tue, 18 Jun 2024 22:14:43 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org CFA1B388302E
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1718748883;
	bh=1PKGCte/2W/HavSZom1EWlgMaM7QqXsHymeZqLR/oPM=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=CQ6ZEh+UhBr/QN7GdJpplis/FULpsKXADeym3x2hoiXrYkqr8Ew2P+F4mGxdsR6Bw
	 4PKiREQKpX/TxEX+RhlI9G+yU0lPaY44s809ZIIwZpZOrbIkX+c/U6rHVlDCM7MMuv
	 61VefdrdBRlFcjcC4w7MCJdZ+P4WiBBUkiGK9Vqg=
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/115544] ICE: in lower_complexexpr_stmt, at
 gimple-lower-bitint.cc:4719 with -O -fno-tree-fre -fno-tree-ccp
 -fno-tree-forwprop and _BitInt() __builtin_mul_overflow()
Date: Tue, 18 Jun 2024 22:14:43 +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: 15.0
X-Bugzilla-Keywords: ice-on-valid-code
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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-115544-4-ytPuyklS0y@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-115544-4@http.gcc.gnu.org/bugzilla/>
References: <bug-115544-4@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=3D115544

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note the gimple stmt/complex_expr in this case:
  _6 =3D COMPLEX_EXPR <a.0_1, 0>;


where _6 is fully unused.

Complex lowering changes:
  _6 =3D COMPLEX_EXPR <a.0_1, 0>;
  _2 =3D REALPART_EXPR <_6>;

into:
  _6 =3D COMPLEX_EXPR <a.0_1, 0>;
  _2 =3D a.0_1;

Which is totally correct though it does not do any DCE.
I am not sure if complex lowering should do some simple DCE or if it matter=
s if
it does not do it.=