gcc/testsuite/gcc.dg/graphite/interchange-8.c

#define DEBUG 0
#if DEBUG
#include <stdio.h>
#endif

int B[4];
int A[4][4][4][4];

static int __attribute__((noinline))
foo (void)
{
  int i, j, k, l;

  /* Loops (L, J) are interchanged, and then loops (J and K) are
     interchanged.  The result is a nest starting with (K, J, L).  */
  for (l = 0; l < 4; l++)
    {
      for (k = 0; k < 4; k++)
	{
	  for (j = 0; j < 4; j++)
	    {
	      for (i = 0; i < 2; i++)
		{
		  B[i] = A[i][k][j][l] + A[3 - i][k][j][l];
		  B[3 - i] = A[i][k][j][l] - A[3 - i][k][j][l];
		}
	      A[0][k][j][l] = B[0] + B[1];
	      A[2][k][j][l] = B[0] - B[1];
	      A[1][k][j][l] = B[3] + B[2];
	      A[3][k][j][l] = B[3] - B[2];
	    }

	  for (i = 0; i < 4; i++)
	    {
	      for (j = 0; j < 2; j++)
		{
		  B[j] = A[i][k][j][l] + A[i][k][3 - j][l];
		  B[3 - j] = A[i][k][j][l] - A[i][k][3 - j][l];
		}
	      A[i][k][0][l] = B[0] + B[1];
	      A[i][k][2][l] = B[0] - B[1];
	      A[i][k][1][l] = B[3] + B[2];
	      A[i][k][3][l] = B[3] - B[2];
	    }
	}
    }

  return A[0][1][0][2] + A[0][3][0][3] + A[0][2][0][2] + A[0][1][0][1] + A[3][3][0][2];
}

extern void abort ();

int
main (void)
{
  int i, j, k, l, res;

  for (i = 0; i < 4; i++)
    B[i] = 2;

  for (i = 0; i < 4; i++)
    for (j = 0; j < 4; j++)
      for (k = 0; k < 4; k++)
	for (l = 0; l < 4; l++)
	  A[i][j][k][l] = i + j + k + l;

  res = foo ();

#if DEBUG
  for (i = 0; i < 4; i++)
    for (j = 0; j < 4; j++)
      for (k = 0; k < 4; k++)
	for (l = 0; l < 4; l++)
	  fprintf (stderr, "A[%d][%d][%d][%d] = %d \n", i, j, k, l, A[i][j][k][l]);

  fprintf (stderr, "res = %d \n", res);
#endif

  if (res != 424)
    abort ();

  return 0;
}

/* { dg-final { scan-tree-dump "tiled by" "graphite" } } */