1  #include <stddef.h>
       2  
       3  struct S {
       4    int i;
       5    int j;
       6  };
       7  struct R {
       8    int k;
       9    struct S a;
      10  };
      11  struct Q {
      12    float k;
      13    struct S a;
      14  };
      15  struct Q s;
      16  int __attribute__((noinline,noclone))
      17  test1 (void *q)
      18  {
      19    struct S *b = (struct S *)((char *)q + sizeof (int));
      20    s.a.i = 0;
      21    b->i = 3;
      22    return s.a.i;
      23  }
      24  int __attribute__((noinline,noclone))
      25  test2 (void *q)
      26  {
      27    struct S *b = &((struct R *)q)->a;
      28    s.a.i = 0;
      29    b->i = 3;
      30    return s.a.i;
      31  }
      32  int __attribute__((noinline,noclone))
      33  test3 (void *q)
      34  {
      35    s.a.i = 0;
      36    ((struct S *)((char *)q + sizeof (int)))->i = 3;
      37    return s.a.i;
      38  }
      39  extern void abort (void);
      40  int
      41  main()
      42  {
      43    if (sizeof (float) != sizeof (int)
      44        || offsetof (struct R, a) != sizeof (int)
      45        || offsetof (struct Q, a) != sizeof (int))
      46      return 0;
      47    s.a.i = 1;
      48    s.a.j = 2;
      49    if (test1 ((void *)&s) != 3)
      50      abort ();
      51    s.a.i = 1;
      52    s.a.j = 2;
      53    if (test2 ((void *)&s) != 3)
      54      abort ();
      55    s.a.i = 1;
      56    s.a.j = 2;
      57    if (test3 ((void *)&s) != 3)
      58      abort ();
      59    return 0;
      60  }