[Bug c++/108214] New: writinng bitset to stringstream fails

[Bug c++/108214] New: writinng bitset to stringstream fails

[rhalbersma at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108214

            Bug ID: 108214
           Summary: writinng bitset to stringstream fails
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rhalbersma at gmail dot com
  Target Milestone: ---

#include <bitset>
#include <sstream>

int main() {
    using T = std::bitset<1>;
    T a(1);
    T b;
    std::stringstream sstr;
    sstr << a;
    sstr >> b;
}

The above program works correctly for g++ until version 12, but for version 13
(trunk) it errors out with: "terminate called after throwing an instance of
'std::invalid_argument' what():  bitset::_M_copy_from_ptr"

Godbolt link: https://godbolt.org/z/nnKT6cddb

[Bug libstdc++/108214] [13 Regression] writinng bitset to stringstream fails

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108214

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-12-23
     Ever confirmed|0                           |1
   Target Milestone|---                         |13.0
            Summary|writinng bitset to          |[13 Regression] writinng
                   |stringstream fails          |bitset to stringstream
                   |                            |fails
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I suspect r13-2998-g1c12a3cfdfabf6 is causing this.

Confirmed.

[Bug libstdc++/108214] [13 Regression] writinng bitset to stringstream fails

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108214

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

[Bug libstdc++/108214] [13 Regression] writinng bitset to stringstream fails

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108214

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:553332c19a04ad0a6bbdd2aafc3499a1cb4dfa0c

commit r13-5048-g553332c19a04ad0a6bbdd2aafc3499a1cb4dfa0c
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Jan 6 13:42:07 2023 +0000

    libstdc++: Fix misuse of alloca in std::bitset [PR108214]

    The use of alloca in a constructor is wrong, because the memory is gone
    after the constructor returns, and will be overwritten by a subsequent
    function call. This didn't show up in testing because function inlining
    alters the stack usage.

    libstdc++-v3/ChangeLog:

            PR libstdc++/108214
            * include/std/bitset (operator>>): Use alloca in the right
            scope, not in a constructor.
            * testsuite/20_util/bitset/io/input.cc: Check case from PR.

[Bug libstdc++/108214] [13 Regression] writinng bitset to stringstream fails

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108214

Jonathan Wakely <redi at gcc dot gnu.org> changed:

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

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Dumb mistake fixed, thanks for the report!