if (IsNullValueAnalysis.DEBUG) { System.out.println("resulting in" + this);  }
	public void mergeKnownValuesWith(IsNullValueFrame otherFrame) {		assert trackValueNumbers;		Map<ValueNumber, IsNullValue> replaceMap = new HashMap<ValueNumber, IsNullValue>();		for (Map.Entry<ValueNumber, IsNullValue> entry : knownValueMap.entrySet()) {			IsNullValue otherKnownValue = otherFrame.knownValueMap.get(entry.getKey());			if (otherKnownValue == null) {				continue;			}			IsNullValue mergedValue = IsNullValue.merge(entry.getValue(), otherKnownValue);			replaceMap.put(entry.getKey(), mergedValue);			if (IsNullValueAnalysis.DEBUG && !mergedValue.equals(entry.getValue())) {					System.out.println("Updated information for " + entry.getKey());					System.out.println("                    was " + entry.getValue());					System.out.println("           merged value " + mergedValue);			}		}		knownValueMap.clear();		knownValueMap.putAll(replaceMap);	}