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From: "anlauf at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/114827] Valgrind reports errors with class(*)
 assignment
Date: Wed, 24 Apr 2024 19:47:53 +0000
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X-Bugzilla-Keywords: wrong-code
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114827

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-04-24
           Keywords|                            |wrong-code

--- Comment #5 from anlauf at gcc dot gnu.org ---
Confirmed.

Two data points which give a hint what might be wrong:

1) the valgrind error count at runtime depends on the string length passed
   to foo.  I get no errors for a string of length 1.

2) the dump-tree of subroutine foo looks suspicious:

    if (b->_data =3D=3D 0B)
      {
        b->_data =3D __builtin_malloc (MAX_EXPR <(unsigned long)
rhs.1._vptr->_size, 1>);

It looks like _size comes from:

  static struct __vtype_CHARACTER_1_ __vtab_CHARACTER_1_ =3D {._hash=3D8589=
3463,
._size=3D1, ._extends=3D0B, ._def_init=3D0B, ._copy=3D__copy_character_1, .=
_final=3D0B};

and is always 1.  On the other hand, subroutine run sets:

        class.2._vptr =3D (struct __vtype__STAR * {ref-all})
&__vtab_CHARACTER_1_;
        class.2._data =3D (void *) &"fubarfubarfubarfubarfubarfu"[1]{lb: 1 =
sz:
1};
        class.2._len =3D 27;

but _len is used in foo for the _copy, but not for the allocation.

Thus the size allocated needs to be fixed.

Changing the character argument to use kind=3D4, I see that _size seems to
represent the element size.

The allocation size thus should be changed to (_size * _len).

Need to find the place where this happens...  Anyone?=