/**
  * Update the value graph to account for a given ASTORE instruction.
  *
  * <p><b>PRECONDITION:</b> <code> AStore.conforms(s); </code> Make sure we have value graph nodes
  * for a constant value
  *
  * @param s the instruction in question
  */
 private void processAStore(Instruction s) {
   Operand value = AStore.getValue(s);
   if (value.isConstant()) {
     findOrCreateVertex((ConstantOperand) value);
   }
   Operand index = AStore.getIndex(s);
   if (index.isConstant()) {
     findOrCreateVertex((ConstantOperand) index);
   }
 }
 /**
  * Update the value graph to account for a given ALOAD instruction.
  *
  * <p><b>PRECONDITION:</b> <code> ALoad.conforms(s); </code> Make sure we have value graph nodes
  * for a constant value
  *
  * @param s the instruction in question
  */
 private void processALoad(Instruction s) {
   Operand index = ALoad.getIndex(s);
   if (index.isConstant()) {
     findOrCreateVertex((ConstantOperand) index);
   }
 }
 /**
  * Update the value graph to account for a given PUTSTATIC instruction.
  *
  * <p><b>PRECONDITION:</b> <code> PutStatic.conforms(s); </code> Make sure we have value graph
  * nodes for a constant value
  *
  * @param s the instruction in question
  */
 private void processPutStatic(Instruction s) {
   Operand value = PutStatic.getValue(s);
   if (value.isConstant()) {
     findOrCreateVertex((ConstantOperand) value);
   }
 }
 /**
  * Add a node to the value graph for every symbolic register.
  *
  * <p><b>PRECONDITION:</b> register lists are computed and valid
  *
  * @param ir the governing IR
  */
 private void addRegisterNodes(IR ir) {
   for (Register reg = ir.regpool.getFirstSymbolicRegister(); reg != null; reg = reg.getNext()) {
     findOrCreateVertex(reg);
   }
 }