1  /* PR tree-optimization/33136 */
       2  /* { dg-do run } */
       3  /* { dg-options "-O2" } */
       4  
       5  extern void abort (void);
       6  
       7  struct S
       8  {
       9    void *a;
      10    int b;
      11    int *c;
      12  };
      13  static int d, e;
      14  
      15  static struct S s;
      16  
      17  static int *
      18  __attribute__((noinline, const))
      19  foo (void)
      20  {
      21    return &s.b;
      22  }
      23  
      24  int *
      25  __attribute__((noinline))
      26  bar (int **f)
      27  {
      28    s.c = &d;
      29    *f = &e;
      30    /* As nothing ever takes the address of any int * field in struct S,
      31       the write to *f can't alias with the s.c field.  */
      32    return s.c;
      33  }
      34  
      35  int
      36  __attribute__((noinline))
      37  baz (int *x)
      38  {
      39    s.b = 1;
      40    *x = 4;
      41    /* Function foo takes address of an int field in struct S,
      42       so *x can alias with the s.b field (and it does in this testcase).  */
      43    return s.b;
      44  }
      45  
      46  int
      47  __attribute__((noinline))
      48  t (void)
      49  {
      50    int *f = (int *) 0;
      51    return 10 * (bar (&f) != &d) + baz (foo ());
      52  }
      53  
      54  int
      55  main (void)
      56  {
      57    if (t () != 4)
      58      abort ();
      59    return 0;
      60  }