1  /* { dg-do run } */
       2  /* { dg-options "-O2" } */
       3  
       4  struct emac {
       5          unsigned reg[23];
       6  };
       7  
       8  struct mop {
       9          unsigned long long addr;
      10          unsigned int size;
      11  };
      12  
      13  unsigned int __attribute__((__noinline__))
      14  level(const struct emac *obj)
      15  {
      16  	return 0;
      17  }
      18  
      19  void __attribute__((__noinline__))
      20  info(struct emac *dev, unsigned long long addr)
      21  {
      22  	asm("" : : : "memory");
      23  }
      24  
      25  unsigned long long __attribute__((__noinline__))
      26  get_value(const struct mop *mop)
      27  {
      28          return 0x1234567890abcdefull;
      29  }
      30  
      31  int __attribute__((__noinline__))
      32  emac_operation(struct emac *obj, struct mop *mop)
      33  {
      34          unsigned long long addr = mop->addr;
      35          int index = addr >> 2;
      36  	unsigned int value, old_value;
      37  
      38          if (mop->size != 4)
      39                  return 0;
      40  
      41          if (index >= 23) {
      42                  if (level(obj) >= 1)
      43                          info(obj, addr);
      44                  return 0;
      45          }
      46  
      47          value = get_value(mop);
      48          old_value = obj->reg[index];
      49  
      50          info(obj, 0);
      51  
      52          switch (index) {
      53          case 0:
      54                  obj->reg[0] = old_value;
      55                  break;
      56          case 7:
      57          case 8:
      58                  obj->reg[index] = value;
      59                  break;
      60          }
      61  
      62          return 0;
      63  }
      64  
      65  int main(void)
      66  {
      67  	struct emac e = { { 0 } };
      68  	struct mop mop = { 32, 4 };
      69  
      70  	e.reg[8] = 0xdeadbeef;
      71  	emac_operation(&e, &mop);
      72  
      73  	if (e.reg[8] != 0x90abcdef)
      74  	   __builtin_abort();
      75  
      76  	   return 0;
      77  }