[Bug c++/66450] New: [5 Regression][C++11][constexpr] Issues when delegating implicit copy constructor in constexpr function

[Bug c++/66450] New: [5 Regression][C++11][constexpr] Issues when delegating implicit copy constructor in constexpr function

[mosra at centrum dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66450

            Bug ID: 66450
           Summary: [5 Regression][C++11][constexpr] Issues when
                    delegating implicit copy constructor in constexpr
                    function
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mosra at centrum dot cz
  Target Milestone: ---

The following code is compiled fine in both GCC 4.9.2 and Clang 3.6:

    struct foo {
        constexpr foo(int a);

        constexpr foo(int a, int b, int c): a{a}, b{b}, c{c} {}

        int a, b, c;
    };

    constexpr foo make_foo(int a) { return foo{a, a+1, a+2}; }

    constexpr foo::foo(int a): foo{make_foo(a)} {}

    int main() {
        constexpr const foo f{3};
        static_assert(f.a == 3, "");
        static_assert(f.b == 4, "");
        static_assert(f.c == 5, "");
    }

In GCC 5.1 it produces an error about non-constant condition for static
assertion. If the relevant lines are changed to runtime assert (and #include
<cassert> added):

        assert(f.a == 3);
        assert(f.b == 4);
        assert(f.c == 5);

Then all three assertions fail at runtime, because the copy constructor is
somehow not called and the structure is instead just zeroed out. HOWEVER, if
you remove all occurrences of the constexpr keyword, the code compiles, no
runtime assertion is fired and everything behaves as expected.

The behavior is the same for -std=c++11 and -std=c++14.

I think the static assertion error and the zero-initialization are somehow
related, so I put these into single issue instead of creating two separate
ones.

[Bug c++/66450] [5 Regression][C++11][constexpr] Issues when delegating implicit copy constructor in constexpr function

[daniel.kruegler at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66450

Daniel Krügler <daniel.kruegler at googlemail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |daniel.kruegler@googlemail.
                   |                            |com

--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
The problem also occurs in gcc HEAD 6.0.0 20150607 (experimental)
>From gcc-bugs-return-488407-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon Jun 08 18:04:39 2015
Return-Path: <gcc-bugs-return-488407-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Delivered-To: listarch-gcc-bugs@gcc.gnu.org
Received: (qmail 33442 invoked by alias); 8 Jun 2015 18:04:39 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Delivered-To: mailing list gcc-bugs@gcc.gnu.org
Received: (qmail 33414 invoked by uid 48); 8 Jun 2015 18:04:34 -0000
From: "anlauf at gmx dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/66461] ICE on missing end program in fixed source
Date: Mon, 08 Jun 2015 18:04:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: fortran
X-Bugzilla-Version: 5.1.1
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: anlauf at gmx dot de
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: cc
Message-ID: <bug-66461-4-7c2NluP4lj@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-66461-4@http.gcc.gnu.org/bugzilla/>
References: <bug-66461-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2015-06/txt/msg00739.txt.bz2
Content-length: 1136

https://gcc.gnu.org/bugzilla/show_bug.cgi?idf461

Harald Anlauf <anlauf at gmx dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |anlauf at gmx dot de

--- Comment #1 from Harald Anlauf <anlauf at gmx dot de> ---
(In reply to Gerhard Steinmetz from comment #0)
> A missing end program in a "fixed" source s.f :
>       program p
>          integer x(2)
>          x = 0
>          if ( x(1) < 0 .or.
>      &        x(2) < 0 ) print *, x
>       !end
>
> yields :
> f951: internal compiler error: free_expr0(): Bad expr type

That's obviously an old regression:

gcc/4.4.5:

pr66451.f:4.27:

         if ( x(1) < 0 .or.
                           1
Error: Syntax error in expression at (1)
Error: Unexpected end of file in 'pr66451.f'

gcc/4.5.2:

pr66451.f:4.9:

         if ( x(1) < 0 .or.
         1
Internal Error at (1):
free_expr0(): Bad expr type

[Bug c++/66450] [5 Regression][C++11][constexpr] Issues when delegating implicit copy constructor in constexpr function

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66450

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Thu Jun 11 15:45:01 2015
New Revision: 224381

URL: https://gcc.gnu.org/viewcvs?rev=224381&root=gcc&view=rev
Log:
        PR c++/66450
        * constexpr.c (cxx_eval_store_expression): Avoid messing up outer
        ctx->ctor.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/constexpr-fwctor1.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/constexpr.c

[Bug c++/66450] [5 Regression][C++11][constexpr] Issues when delegating implicit copy constructor in constexpr function

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66450

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Wed Jun 17 14:33:02 2015
New Revision: 224557

URL: https://gcc.gnu.org/viewcvs?rev=224557&root=gcc&view=rev
Log:
        PR c++/66450
        * constexpr.c (cxx_eval_store_expression): Avoid messing up outer
        ctx->ctor.

Added:
    branches/gcc-5-branch/gcc/testsuite/g++.dg/cpp0x/constexpr-fwctor1.C
Modified:
    branches/gcc-5-branch/gcc/cp/ChangeLog
    branches/gcc-5-branch/gcc/cp/constexpr.c

[Bug c++/66450] [5 Regression][C++11][constexpr] Issues when delegating implicit copy constructor in constexpr function

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66450

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
             Blocks|                            |55004
         Resolution|---                         |FIXED
   Target Milestone|---                         |5.2

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Fixed then.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55004
[Bug 55004] [meta-bug] constexpr issues