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 BB4603850234; Sat, 25 Jun 2022 00:52:05 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BB4603850234
From: "foom at fuhm dot net" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/101836] __builtin_object_size(P->M, 1) where M is an
 array and the last member of a struct fails
Date: Sat, 25 Jun 2022 00:52:05 +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: 12.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: enhancement
X-Bugzilla-Who: foom at fuhm dot net
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: qinzhao at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc
Message-ID: <bug-101836-4-x9nnzmJi3r@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-101836-4@http.gcc.gnu.org/bugzilla/>
References: <bug-101836-4@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
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Sat, 25 Jun 2022 00:52:05 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101836

James Y Knight <foom at fuhm dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |foom at fuhm dot net

--- Comment #31 from James Y Knight <foom at fuhm dot net> ---
It doesn't make sense to have a mode in which `int array[0]` is accepted bu=
t is
not a flex array.

Either that should be a compilation error (as the standard specifies), or it
should be a flex array. Accepting it as an extension but having it do the w=
rong
thing is not useful or helpful.

Note that Clang has a dedicated warning flag for zero-length arrays:
-Wzero-length-array, so anyone who wants to prohibit them may use
-Werror=3Dzero-length-array. It would be helpful for GCC could follow suit =
there.

The other proposed modes:
- Treat all trailing arrays as flexible arrays. the default behavior;
- Only treating [], [0], and [1] as flexible array;
- Only treating [] and [0] as flexible array;
do make sense.=