Viewing file:  interchange-8.c (1.67 KB) -rw-r--r--
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#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" } } */
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