1  /* { dg-do run } */
       2  
       3  struct list { struct list *n; };
       4  
       5  struct obj {
       6      int n;
       7      struct list l;
       8  } _o;
       9  
      10  struct list _l = { .n = &_o.l };
      11  
      12  int main(int argc, char *argv[])
      13  {
      14    struct obj *o = &_o;
      15    _o.l.n = &_l;
      16    while (&o->l != &_l)
      17      /* Note the following is invoking undefined behavior but in
      18         this kind of "obvious" cases we don't want to break things
      19         unnecessarily and thus we avoid analyzing o as pointing
      20         to nothing via the undefined pointer subtraction.  Instead
      21         we canonicalize the pointer subtraction followed by the
      22         pointer conversion to pointer offsetting.  */
      23      o = ((struct obj *)((const char *)(o->l.n)
      24  			- (const char *)&((struct obj *)0)->l));
      25    return 0;
      26  }