}
} else { derefLocationSetMap.put(vn, new HashSet<Location>(fact.getDerefLocationSet(vn))); }
	public void unionWith(UnconditionalValueDerefSet fact, ValueNumberFactory valueNumberFactory) {		// Compute the union of the unconditionally dereferenced value sets		valueNumberSet.or(fact.valueNumberSet);		// For each unconditionally dereferenced value...		for (int i = 0; i < numValueNumbersInMethod; i++) {			ValueNumber vn = valueNumberFactory.forNumber(i);			if (fact.valueNumberSet.get(i)) {				// Compute the union of the dereference locations for				// this value number.				Set<Location> derefLocationSet = derefLocationSetMap.get(vn);				if (derefLocationSet == null) {					derefLocationSet = new HashSet<Location>();					derefLocationSetMap.put(vn,derefLocationSet);				}				derefLocationSet.addAll(fact.derefLocationSetMap.get(vn));			} 		}	}