[Bug c++/113767] New: Missing Destructor Call with goto and return value

[Bug c++/113767] New: Missing Destructor Call with goto and return value

[joerg.richter@pdv-fs.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113767

            Bug ID: 113767
           Summary: Missing Destructor Call with goto and return value
           Product: gcc
           Version: 13.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: joerg.richter@pdv-fs.de
  Target Milestone: ---

#include <cstdio>

struct S
{

    S()
    {
      printf( "Cons\n" );
    }

    ~S()
    {
      printf( "Dest\n" );
    }
};

S func()
{
  bool first = true;

restart:
  S ss;
  if( first )
  {
    first = false;
    goto restart;
  }
  return ss;
}

int main()
{
    func();
}

Output:
Cons
Cons
Dest

Expected Output:
Cons
Dest
Cons
Dest


https://godbolt.org/z/9n6nnv18P

Seems to be fixed in trunk but not on any released branch. Can the fix be
integrated to the released branches?

[Bug c++/113767] [11/12/13 Regression] Missing Destructor Call with goto and return value

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113767

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|needs-bisection             |
   Target Milestone|---                         |13.3
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |ppalka at gcc dot gnu.org
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=92407
            Summary|Missing Destructor Call     |[11/12/13 Regression]
                   |with goto and return value  |Missing Destructor Call
                   |                            |with goto and return value

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed on trunk after r14-1593-g7e0b65b239c3a0, where we get the expected output

Cons
Dest
Cons
Dest

and indeed this seems closely related or even a dup of PR92407 the fix for
which has been backported for 11.5/12.4/13.3/14.

However, using the latest 13/12/11 release branches containing the backported
fix I see we now output

Cons
Dest
Cons
Dest
Dest

instead of

Cons
Cons
Dest

which still seems wrong?  (Not sure if generating different wrong code is
considered a regression..)

[Bug c++/113767] [11/12/13 Regression] Missing Destructor Call with goto and return value

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113767

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |jason at gcc dot gnu.org
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-02-05
             Status|UNCONFIRMED                 |ASSIGNED

[Bug c++/113767] [11/12/13 Regression] Missing Destructor Call with goto and return value

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113767

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1

[Bug c++/113767] [11/12/13 Regression] Missing Destructor Call with goto and return value

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113767

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

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

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
The fix on the branches is just to disable NRV in the presence of backward
goto, as the fix on the trunk was too involved to backport.

So this testcase no longer puts ss in the return slot in 11/12/13, but instead
returns a copy; the extra destructor call is for the copy.  It looks mismatched
because there's no user-defined copy constructor to add another "Cons" line;
adding that makes it look better.

*** This bug has been marked as a duplicate of bug 92407 ***