1  extern void abort (void) __attribute__ ((noreturn));
       2  
       3  #define MARGIN 6
       4  
       5  void __attribute__ ((weak, optimize ("no-tree-vectorize")))
       6  test (int n, int m, int offset)
       7  {
       8    int abs_n = (n < 0 ? -n : n);
       9    int abs_m = (m < 0 ? -m : m);
      10    int max_i = (abs_n > abs_m ? abs_n : abs_m);
      11    int abs_offset = (offset < 0 ? -offset : offset);
      12    int size = MARGIN * 2 + max_i * SIZE + abs_offset;
      13    TYPE *array = (TYPE *) __builtin_alloca (size * sizeof (TYPE));
      14    for (int i = 0; i < size; ++i)
      15      array[i] = i;
      16    int base_x = offset < 0 ? MARGIN - offset : MARGIN;
      17    int base_y = offset < 0 ? MARGIN : MARGIN + offset;
      18    int start_x = n < 0 ? base_x - n * (SIZE - 1) : base_x;
      19    int start_y = m < 0 ? base_y - m * (SIZE - 1) : base_y;
      20    f (&array[start_x], &array[start_y], n, m);
      21    int j = 0;
      22    int start = (n < 0 ? size - 1 : 0);
      23    int end = (n < 0 ? -1 : size);
      24    int inc = (n < 0 ? -1 : 1);
      25    for (int i = start; i != end; i += inc)
      26      {
      27        if (j == SIZE || i != start_x + j * n)
      28  	{
      29  	  if (array[i] != i)
      30  	    abort ();
      31  	}
      32        else if (n == 0)
      33  	{
      34  	  TYPE sum = i;
      35  	  for (; j < SIZE; j++)
      36  	    {
      37  	      int next_y = start_y + j * m;
      38  	      if (n >= 0 ? next_y < i : next_y > i)
      39  		sum += array[next_y];
      40  	      else if (next_y == i)
      41  		sum += sum;
      42  	      else
      43  		sum += next_y;
      44  	    }
      45  	  if (array[i] != sum)
      46  	    abort ();
      47  	}
      48        else
      49  	{
      50  	  int next_y = start_y + j * m;
      51  	  TYPE base = i;
      52  	  if (n >= 0 ? next_y < i : next_y > i)
      53  	    base += array[next_y];
      54  	  else
      55  	    base += next_y;
      56  	  if (array[i] != base)
      57  	    abort ();
      58  	  j += 1;
      59  	}
      60      }
      61  }