gcc/testsuite/gcc.dg/graphite/pr69292.c

/* { dg-options "-O2 -floop-nest-optimize" } */

int m[1];

void
foo (double a[20][20], double b[20])
{
  int i, j, k;

  for (i = 0; i < m[0]; ++i)
    for (j = 0; j < m[0]; ++j)
      a[i][j] = a[i][j] + 1;

  for (k = 0; k < 20; ++k)
    for (i = 0; i < m[0]; ++i)
      for (j = 0; j < m[0]; ++j)
	b[i] = b[i] + a[i][j];
}