Given two inclusive ranges [x1:x2] and [y1:y2], where `x1 ≤ x2` and `y1 ≤ y2`, what is the most efficient way to test whether there is any overlap of the two ranges?

A simple implementation is as follows:

```
bool testOverlap(int x1, int x2, int y1, int y2) {
  return (x1 >= y1 && x1 <= y2) ||
         (x2 >= y1 && x2 <= y2) ||
         (y1 >= x1 && y1 <= x2) ||
         (y2 >= x1 && y2 <= x2);
}

```

But I expect there are more efficient ways to compute this.

What method would be the most efficient in terms of fewest operations?