anchor.diff:      tdb_update([{Src,{tuple,Arity,[]}}], Ts0);
   update({test,is_map,_Fail,[Src]}, Ts0) ->
       tdb_update([{Src,map}], Ts0);
  +update({get_map_elements,_,Src,{list,Elems0}}, Ts0) ->
  +    {_Ss,Ds} = beam_utils:split_even(Elems0),
  +    Elems = [{Dst,kill} || Dst <- Ds],
  +    tdb_update([{Src,map}|Elems], Ts0);
   update({test,is_nonempty_list,_Fail,[Src]}, Ts0) ->
       tdb_update([{Src,nonempty_list}], Ts0);
   update({test,is_eq_exact,_,[Reg,{atom,_}=Atom]}, Ts) ->
  
positive.code: 
  -import(lists, [filter/2,foldl/3,keyfind/3,member/2,
  		reverse/1,reverse/2,sort/1]).
  
  -spec module(beam_utils:module_code(), [compile:option()]) ->
                      {'ok',beam_utils:module_code()}.
  
negative.code: update({call,_Arity,_Func}, Ts) -> tdb_kill_xregs(Ts);
  update({call_ext,_Arity,_Func}, Ts) -> tdb_kill_xregs(Ts);
  update({make_fun2,_,_,_,_}, Ts) -> tdb_kill_xregs(Ts);
  update({call_fun, _}, Ts) -> tdb_kill_xregs(Ts);
  update({apply, _}, Ts) -> tdb_kill_xregs(Ts);
  
  update({line,_}, Ts) -> Ts;
  
  %% The instruction is unknown.  Kill all information.
  update(_I, _Ts) -> tdb_new().
  