1  
       2  extern void abort(void);
       3  
       4  __attribute__ ((noinline))
       5  int foo(int n)
       6  {
       7    if (n < 0)
       8      n = ~n;
       9  
      10    return n;
      11  }
      12  
      13  int main(void)
      14  {
      15    if (foo (-1) != 0)
      16      abort ();
      17  
      18    return 0;
      19  }