PVS-Studio warning V609 for VNL

integer pow_ii(integer *ap, integer *bp)
{
  integer pow, x, n;
  unsigned long u;

  x = *ap;
  n = *bp;

  if (n <= 0)
  {
    if (n == 0 || x == 1)
      return 1;

    if (x != -1)
      return x == 0 ? 1/x : 0;

    n = -n;
  }
  ....
}

This suspicious code was found in VNL project by PVS-Studio static code analyzer.
Warning message is:
V609 Divide by zero. Denominator 'x' == 0. pow_ii.c 28

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