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 3DFE73858414; Mon,  4 Mar 2024 12:27:38 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 3DFE73858414
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1709555258;
	bh=hivCdZS+lpzwkL+UgCkMyPCDXxypovP+KXkXhoPfunQ=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=IvcR7xaWgOr6cHgQpRV6BBP8X3tYC1AjkS66HV0zvAnrhWc6miIqG3hrA+2xFyAx/
	 p8ytgVCaROeWlhmtI59uwqDstcE9APsOZxFW5S6inZxOsUP2pB+01HweZO/+BJm5IA
	 FGN0atEhKGpazd8VSbLia/KSHIIJ1FQmnetsOIEc=
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/114197] [14 regression] ICE in verify_dominators
Date: Mon, 04 Mar 2024 12:27:37 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: ice-on-valid-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rguenth at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: rguenth at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 14.0
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-114197-4-DyrDnsPaUw@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-114197-4@http.gcc.gnu.org/bugzilla/>
References: <bug-114197-4@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=3D114197

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue is really unexpected if-conversion which ends up putting the
vector copy of an innner loop outside of the enclosing loop of a scalar
loop.  Such mishap usually happens because of simplifications.

In this case we see bitfield lowering touching a volatile access which
it shouldn't do, even removing the volatile marking and then value-numbering
concluding the lowered d.b is 5:

Value numbering stmt =3D _ifc__21 =3D d.D.2770;
RHS d.D.2770 simplified to 5
Setting value number of _ifc__21 to 5 (changed)
Replaced d.D.2770 with 5 in all uses of _ifc__21 =3D d.D.2770;
Value numbering stmt =3D _ifc__22 =3D BIT_FIELD_REF <_ifc__21, 8, 0>;
Match-and-simplified BIT_FIELD_REF <_ifc__21, 8, 0> to 5
RHS BIT_FIELD_REF <_ifc__21, 8, 0> simplified to 5
Setting value number of _ifc__22 to 5 (changed)
Replaced BIT_FIELD_REF <_ifc__21, 8, 0> with 5 in all uses of _ifc__22 =3D
BIT_FIELD_REF <_ifc__21, 8, 0>;
Value numbering stmt =3D _1 =3D _ifc__22;
Setting value number of _1 to 5 (changed)
Value numbering stmt =3D if (_1 =3D=3D 0)
marking known outgoing edge 4 -> 5 executable
gimple_simplified to if (0 !=3D 0)=