1  /* { dg-do compile } */
       2  /* { dg-options "-O2"  } */
       3  
       4  struct A1 {
       5    char a1[1];
       6  };
       7  
       8  void fn2(char a);
       9  
      10  void fn1(struct A1 *p1) {
      11    fn2(p1->a1[-1]);
      12  }