1  typedef struct rtx_def
       2  {
       3    int f1 :1;
       4    int f2 :1;
       5  } *rtx;
       6  
       7  static rtx
       8  f (orig)
       9       register rtx orig;
      10  {
      11    if (orig->f1 || orig->f2)
      12      return orig;
      13    orig->f2 = 1;
      14    return orig;
      15  }
      16  
      17  void
      18  f2 ()
      19  {
      20    abort ();
      21  }
      22  
      23  main ()
      24  {
      25    struct rtx_def foo;
      26    rtx bar;
      27  
      28    foo.f1 = 1;
      29    foo.f2 = 0;
      30    bar = f (&foo);
      31    if (bar != &foo || bar->f2 != 0)
      32      abort ();
      33    exit (0);
      34  }