Below counting down loop in "bar()" should be vectorizable by C2 superword. But actually it's not. We should investigate why. Initial investigation shows that no valid SWPointer is found for this pattern.
```
  private static final int SIZE = 2345;
  private static int[] a = new int[SIZE];
  private static int[] b = new int[SIZE];

  public static void bar() {
      for (int i = 1000; i > 0; i--) {
          b[SIZE - i] = a[SIZE - i];
      }
  }
```