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 0096C3858D1E; Tue, 24 Jan 2023 18:27:04 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 0096C3858D1E
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1674584825;
	bh=22sA67MCiYe90kQW3vHyOgPhU7ynKziJtRVas7Q2Z2U=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=g4sZM2cDiVZjw3RGZEFbZYfivKdozPcntTH3QOGNbgxa4M3oPOsKL+H2pqQH8oWpX
	 ehNYHqEr+wfph8ofwF2spMqBnl5YH6ytZrw7l99one6fk6C3NPJaIcjnS68l2u4c70
	 HZH4XcMd4ssJvQQmZglNdUfuprVDRUtetMDG3PVA=
From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108522] [12/13 Regression] ICE in
 tree-object-size when struct has VLA
Date: Tue, 24 Jan 2023 18:27:04 +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: 13.0
X-Bugzilla-Keywords: ice-on-valid-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jakub at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: siddhesh at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 12.3
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc priority target_milestone
Message-ID: <bug-108522-4-PtqBfRIodx@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-108522-4@http.gcc.gnu.org/bugzilla/>
References: <bug-108522-4@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=3D108522

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
           Priority|P3                          |P2
   Target Milestone|---                         |12.3

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
At least for backports one option can be punt (give the constant maximum or
minimum) when variable length structures are involved, almost nobody uses t=
hem
(with the exception of Ada but then _FORTIFY_SOURCE=3D3 isn't on) and they =
are
quite a mess to support.
Otherwise, one needs to make sure to use TREE_OPERAND (t, 2) of COMPONENT_R=
EF
if non-NULL.
On the above testcase one can see:
  _3 =3D &s.1_9->b{off: _1};
  _12 =3D __builtin_dynamic_object_size (_3, 1);
That {off: _1} in there means COMPONENT_REF's last operand isn't NULL, but =
is
SSA_NAME _1.  That contains something that should be used instead of
DECL_FIELD_OFFSET if specified, because in DECL_FIELD_OFFSET you'll see a
VAR_DECL that contained that value during gimplification, but isn't maintai=
ned
later on.
tree-object-size.cc currently uses byte_position, which is ok if last
COMPONENT_REF's operand is NULL, otherwise it should be
byte_from_pos (TREE_OPERAND (component_ref, 2), DECL_FIELD_BIT_OFFSET (fiel=
d));
where field is TREE_OPERAND (component_ref, 1).=