[Bug c++/49528] New: g++ fails to destroy temporary object when subobject is used to initialize a reference

[Bug c++/49528] New: g++ fails to destroy temporary object when subobject is used to initialize a reference

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

           Summary: g++ fails to destroy temporary object when subobject
                    is used to initialize a reference
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jason@gcc.gnu.org


I believe that r should point to a temporary int and the A temporary destroyed
at the end of the declaration statement rather than have its lifetime extended
to the end of the block.  In any case, never destroying it is clearly broken.

int d;
struct A
{
  int i;
  ~A() { ++d; };
};

int main()
{
  { const int &r = A().i; }
  if (d != 1)
    return 1;
}

[Bug c++/49528] g++ fails to destroy temporary object when subobject is used to initialize a reference

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.06.25 03:33:06
     Ever Confirmed|0                           |1

[Bug c++/49528] [4.6/4.7 regression] g++ fails to destroy temporary object when subobject is used to initialize a reference

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|g++ fails to destroy        |[4.6/4.7 regression] g++
                   |temporary object when       |fails to destroy temporary
                   |subobject is used to        |object when subobject is
                   |initialize a reference      |used to initialize a
                   |                            |reference

--- Comment #1 from Jason Merrill <jason at gcc dot gnu.org> 2011-06-25 03:34:55 UTC ---
Hmm, looks like this worked in 4.5.

[Bug c++/49528] [4.6/4.7 regression] g++ fails to destroy temporary object when subobject is used to initialize a reference

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.6.1

[Bug c++/49528] [4.6/4.7 regression] g++ fails to destroy temporary object when subobject is used to initialize a reference

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |jason at gcc dot gnu.org
                   |gnu.org                     |

[Bug c++/49528] [4.6/4.7 regression] g++ fails to destroy temporary object when subobject is used to initialize a reference

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> 2011-06-26 14:00:37 UTC ---
Author: jason
Date: Sun Jun 26 14:00:33 2011
New Revision: 175409

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=175409
Log:
    PR c++/49528
    * semantics.c (potential_constant_expression_1): A TARGET_EXPR
    with a cleanup isn't constant.
    (cxx_eval_constant_expression): Likewise.
    * init.c (expand_default_init): Use maybe_constant_init.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/constexpr-cleanup.C
    trunk/gcc/testsuite/g++.dg/init/ref19.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/init.c
    trunk/gcc/cp/semantics.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/49528] [4.6 regression] g++ fails to destroy temporary object when subobject is used to initialize a reference

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> 2011-06-27 01:07:38 UTC ---
Author: jason
Date: Mon Jun 27 01:07:34 2011
New Revision: 175417

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=175417
Log:
    PR c++/49528
    * semantics.c (potential_constant_expression_1): Check
    for non-literality rather than cleanup.
    (cxx_eval_constant_expression): Likewise.

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

[Bug c++/49528] [4.6 regression] g++ fails to destroy temporary object when subobject is used to initialize a reference

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.1                       |4.6.2

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-06-27 12:32:51 UTC ---
GCC 4.6.1 is being released.

[Bug c++/49528] [4.6 regression] g++ fails to destroy temporary object when subobject is used to initialize a reference

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> 2011-06-27 20:16:21 UTC ---
Author: jason
Date: Mon Jun 27 20:16:14 2011
New Revision: 175559

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=175559
Log:
    PR c++/49528
    * semantics.c (potential_constant_expression_1): A TARGET_EXPR
    of non-literal type isn't constant.
    (cxx_eval_constant_expression): Likewise.
    * init.c (expand_default_init): Use maybe_constant_init.

Added:
    branches/gcc-4_6-branch/gcc/testsuite/g++.dg/cpp0x/constexpr-cleanup.C
    branches/gcc-4_6-branch/gcc/testsuite/g++.dg/init/ref19.C
Modified:
    branches/gcc-4_6-branch/gcc/cp/ChangeLog
    branches/gcc-4_6-branch/gcc/cp/init.c
    branches/gcc-4_6-branch/gcc/cp/semantics.c
    branches/gcc-4_6-branch/gcc/testsuite/ChangeLog

[Bug c++/49528] [4.6 regression] g++ fails to destroy temporary object when subobject is used to initialize a reference

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49528

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #6 from Jason Merrill <jason at gcc dot gnu.org> 2011-06-27 20:19:23 UTC ---
Fixed for 4.6.2.