[Bug libfortran/69651] New: Usage of unitialized pointer io/list_read.c

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69651

            Bug ID: 69651
           Summary: Usage of unitialized pointer io/list_read.c
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kyukhin at gcc dot gnu.org
  Target Milestone: ---

Unfortunately I have no testcase.

But code itself looks awful to me:
/* Worker function to save a KIND=4 character to a string buffer,
   enlarging the buffer as necessary.  */

static void
push_char4 (st_parameter_dt *dtp, int c)
{
  gfc_char4_t *new, *p = (gfc_char4_t *) dtp->u.p.saved_string;

  if (p == NULL)
    {
      dtp->u.p.saved_string = xcalloc (SCRATCH_SIZE, sizeof (gfc_char4_t));
      dtp->u.p.saved_length = SCRATCH_SIZE;
      dtp->u.p.saved_used = 0;
      p = (gfc_char4_t *) dtp->u.p.saved_string;
    }

  if (dtp->u.p.saved_used >= dtp->u.p.saved_length)
    {
      dtp->u.p.saved_length = 2 * dtp->u.p.saved_length;
      p = xrealloc (p, dtp->u.p.saved_length * sizeof (gfc_char4_t));

      memset4 (new + dtp->u.p.saved_used, 0, // <-- ??? new==junk ???
              dtp->u.p.saved_length - dtp->u.p.saved_used);
    }

  p[dtp->u.p.saved_used++] = c;
}

It was introduced w/ r210948
(https://gcc.gnu.org/ml/fortran/2014-05/msg00149.html). Before that new was [at
least] initialized.