[Bug fortran/54618] [OOP] wrong-code with CLASS(...), INTENT(OUT) -- and OPTIONAL or ALLOCATABLE

["burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54618

--- Comment #9 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-09-25 18:37:26 UTC ---
Created attachment 28275
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28275
Patch for OPTIONAL

This patch fixes the segfaults of the test case in attachment 28269. It also
avoids the copy back of _data/_vptr for class_to_class when it cannot change.

(Note that this patch also fixes the issues of bug 50981 comment 31 and bug
50981 comment 23.)

Still to do:
- Fix CLASS(t), ALLOCATABLE, INTENT(OUT) for arrays (cf. comment 0)
- More test (cf. comment 8 and bug 50981 comment 36)

And the remaining failure of the test case (attachment 28269): For an absent
actual to a1a1,

   subroutine a1a1(z)
     type(t), optional :: z(:)
     call a2(z)

a present PRESENT(x) check in a2 is wrongly .TRUE. The present check is
  if (x != 0B && (struct t[0:] *) x->_data.data != 0B)

The problem is that the argument in a1a1 is handled as:
    parm.5.data = (void *) &(*z.0)[0];
    class.4._data = parm.5;
    a2 (&class.4);