public ThisValue mergeValues(ThisValue a, ThisValue b) {
public ThisValue mergeValues(int slot, ThisValue a, ThisValue b) {
	public ThisValue mergeValues(ThisValue a, ThisValue b) {		if (a.isTop())			return b;		else if (b.isTop())			return a;		else if (a.isBottom() || b.isBottom())			return ThisValue.bottom();		else if (a.equals(b))			return a;		else			return ThisValue.bottom();	}