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 C8FAA385DC1B; Sat,  2 May 2020 14:12:14 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C8FAA385DC1B
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
 s=default; t=1588428734;
 bh=vgDdJs+GqX/d7VckAVMHWweqCjrXLqsj54lmd+Vod9I=;
 h=From:To:Subject:Date:From;
 b=SHaaWFhOWq/kkwvdqVWCcQoBVSopRDkpvpcU+vwVAYlfN+Rnjb+K6dOmOcfAb3Xxt
 hDziKtr4v6ZKWKZ0TZ7DbiGThHbwb4eJPu/Cq0t2RQospcul+xi6kYGRcDUOdCuMlG
 lGM2S2xpPN19OvBTljVhUdbnH8Z9RgyC8oU0DP8c=
From: "rhalbersma at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/94924] New: Default equality operator for C-array compares
 addresses, not data
Date: Sat, 02 May 2020 14:12:14 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 10.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rhalbersma at gmail dot com
X-Bugzilla-Status: UNCONFIRMED
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: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-94924-4@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: <http://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: <http://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Sat, 02 May 2020 14:12:14 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94924

            Bug ID: 94924
           Summary: Default equality operator for C-array compares
                    addresses, not data
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rhalbersma at gmail dot com
  Target Milestone: ---

It appears that the default op=3D=3D for a C-array has array-to-pointer dec=
ay
applied and does not compare the underlying array data.

struct S {
    int data[1];
    bool operator=3D=3D(const S&) const =3D default;
};

int main()
{
    static_assert(S{1} !=3D S{1});
    constexpr auto s =3D S{1};
    static_assert(s =3D=3D s);
}

Tested on tip-of-trunk at Wandbox:
https://wandbox.org/permlink/YxUv5dFs7mSGlNBx

Works correctly on Clang >=3D 10.=