private ValueGraphVertex findOrCreateVertex(Register r){
  ValueGraphVertex v=getVertex(r);
  if (v == null) {
    v=new ValueGraphVertex(r);
    v.setLabel(r,0);
    graph.addGraphNode(v);
    nameMap.put(r,v);
  }
  return v;
}

private ValueGraphVertex findOrCreateVertex ( Register r ) { ValueGraphVertex v = getVertex ( r ) ; if ( v == null ) { v = new ValueGraphVertex ( r ) ; v . setLabel ( r , 0 ) ; graph . addGraphNode ( v ) ; nameMap . put ( r , v ) ; } return v ; }
find or create an valuegraphvertex corresponding to a given register
