1  struct x { 
       2    unsigned x1:1;
       3    unsigned x2:2;
       4    unsigned x3:3;
       5  };
       6     
       7  foobar (int x, int y, int z)
       8  {
       9    struct x a = {x, y, z};
      10    struct x b = {x, y, z};
      11    struct x *c = &b;
      12  
      13    c->x3 += (a.x2 - a.x1) * c->x2;
      14    if (a.x1 != 1 || c->x3 != 5)
      15      abort ();
      16    exit (0);
      17  }
      18  
      19  main()
      20  {
      21    foobar (1, 2, 3);
      22  }
      23