[Bug c++/19544] New: Difference in behaviour if default constructor added

[chris at bubblescope dot net]

While looking at PR 19510, I noticed the following strangeness.

Consider:
--
#include<vector>
struct ptr
{
int* a;
ptr() {}
};
std::vector<ptr> v(1);
--
At -O3 -Wall
This code produces the error message:
...../include/c++/4.0.0/bits/stl_construct.h: In function 'void
__static_initialization_and_destruction_0(int,int)':
...../include/c++/4.0.0/bits/stl_construct.h:81: warning: 'SR.186' is used
uninitalized in this function

This warning is not generated if I declare ptr without a default constructor,
although 12.1/7 seems to imply that the default generated constructor should be
exactly what I have written down.

-- 
           Summary: Difference in behaviour if default constructor added
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: chris at bubblescope dot net
                CC: caj at cs dot york dot ac dot uk,gcc-bugs at gcc dot gnu
                    dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19544