1  /* Spurious uninitialized variable warnings, from gdb */
       2  /* { dg-do compile } */
       3  /* { dg-options "-O2 -Wuninitialized" } */
       4  struct os { struct o *o; };
       5  struct o { struct o *next; struct os *se; };
       6  void f(struct o *o){
       7    struct os *s;
       8    if(o) s = o->se;
       9    while(o && s == o->se){
      10      s++; // here `o' is non-zero and thus s is initialized
      11      s == o->se  // `?' is essential, `if' does not trigger the warning
      12        ? (o = o->next, o ? s = o->se : 0)
      13        : 0;
      14    }
      15  }
      16  
      17  
      18