anchor.diff:                              if dom.[p] <> None then 
                                   newIDom <- inter postorderMap dom p newIDom
                       let x = dom.[b]
  -                    if Option.isNone x || Option.get x <> newIDom then
  +                    if Option.isNone x || Common.Option.get x <> newIDom then
                           dom.[b] <- Some newIDom
                           changed <- true
  -        let res = Dictionary()
  -        for v in cg.Graph.Vertices do 
  -            res.[v] <- dominatorSet dom v
  -        res
  +        DominationTree(dom)
   
   
   module Minimize =
  
positive.code:         | Yes of HashSet<Node>
          | No
  
      let protect (idx: int) (doms: Domination.DominationSet) (cg1,n1) (cg2,n2) : ProtectResult = 
          if loc n1 <> loc n2 then No else
          let q = Queue()
          let seen = HashSet()
  
negative.code:                 y <- po.[finger2]
          finger1
          
      let dominators (cg: T) root direction : DominationTree =
          let adj = if direction = Up then neighbors cg else neighborsIn cg
          let dom = Dictionary()
          let reach = Reachable.postOrder cg root direction
  