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 30F123896C1B; Mon, 29 Nov 2021 08:49:23 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 30F123896C1B
From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a
 constant
Date: Mon, 29 Nov 2021 08:49:23 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 12.0
X-Bugzilla-Keywords: rejects-valid
X-Bugzilla-Severity: normal
X-Bugzilla-Who: cvs-commit 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-102786-4-Y8bDm8z0aC@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-102786-4@http.gcc.gnu.org/bugzilla/>
References: <bug-102786-4@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: Mon, 29 Nov 2021 08:49:23 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102786

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:62e4f0e8977497e01d2c262a3bd459ab26a5aaca

commit r11-9326-g62e4f0e8977497e01d2c262a3bd459ab26a5aaca
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Oct 19 09:24:57 2021 +0200

    c++: Don't reject calls through PMF during constant evaluation [PR10278=
6]

    The following testcase incorrectly rejects the c initializer,
    while in the s.*a case cxx_eval_* sees .__pfn reads etc.,
    in the s.*&S::foo case get_member_function_from_ptrfunc creates
    expressions which use INTEGER_CSTs with type of pointer to METHOD_TYPE.
    And cxx_eval_constant_expression rejects any INTEGER_CSTs with pointer
    type if they aren't 0.
    Either we'd need to make sure we defer such folding till cp_fold but the
    function and pfn_from_ptrmemfunc is used from lots of places, or
    the following patch just tries to reject only non-zero INTEGER_CSTs
    with pointer types if they don't point to METHOD_TYPE in the hope that
    all such INTEGER_CSTs with POINTER_TYPE to METHOD_TYPE are result of
    folding valid pointer-to-member function expressions.
    I don't immediately see how one could create such INTEGER_CSTs otherwis=
e,
    cast of integers to PMF is rejected and would have the PMF RECORD_TYPE
    anyway, etc.

    2021-10-19  Jakub Jelinek  <jakub@redhat.com>

            PR c++/102786
            * constexpr.c (cxx_eval_constant_expression): Don't reject
            INTEGER_CSTs with type POINTER_TYPE to METHOD_TYPE.

            * g++.dg/cpp2a/constexpr-virtual19.C: New test.

    (cherry picked from commit f45610a45236e97616726ca042898d6ac46a082e)=