/**
* Update the value graph to account for a given NullCheck instruction.
*
* <p><b>PRECONDITION:</b> <code> ZeroCheck.conforms(s); </code>
*
* @param s the instruction in question
*/
private void processZeroCheck(Instruction s) {
// label the vertex corresponding to the result with the operator
RegisterOperand result = ZeroCheck.getGuardResult(s);
ValueGraphVertex v = findOrCreateVertex(result.getRegister());
v.setLabel(s.operator(), 1);
// link node v to the operand it uses
Operand val = ZeroCheck.getValue(s);
// bypass Move instructions
val = bypassMoves(val);
link(v, findOrCreateVertex(val), 0);
}
