public BindingSet match(InstructionHandle handle, ConstantPoolGen cpg,
public MatchResult match(InstructionHandle handle, ConstantPoolGen cpg,
	public BindingSet match(InstructionHandle handle, ConstantPoolGen cpg,		ValueNumberFrame before, ValueNumberFrame after, BindingSet bindingSet) throws DataflowAnalysisException {		// Instruction must be IFNULL or IFNONNULL.		Instruction ins = handle.getInstruction();		if (!(ins instanceof IFNULL || ins instanceof IFNONNULL))			return null;		// Ensure reference used is consistent with previous uses of		// same variable.		LocalVariable ref = new LocalVariable(before.getTopValue());		return addOrCheckDefinition(ref, bindingSet);	}