public boolean mayAlias(Value v1,Value v2,Unit u){
  Set<Set<Value>> res=getFlowBefore(u);
  for (  Set<Value> set : res) {
    if (set.contains(v1) && set.contains(v2))     return true;
  }
  return false;
}

public boolean mayAlias ( Value v1 , Value v2 , Unit u ) { Set < Set < Value > > res = getFlowBefore ( u ) ; for ( Set < Value > set : res ) { if ( set . contains ( v1 ) && set . contains ( v2 ) ) return true ; } return false ; }
returns true if v1 and v2 may alias before u .
