anchor.diff:      case beam_utils:is_pure_test(I) of
   	false ->
   	    %% Test is not pure; we must keep it.
  -	    opt(Is, [I|Acc], label_used(Lbl, St));
  +	    opt(Is, [I|Acc0], label_used(Lbl, St0));
   	true ->
   	    %% The test is pure and its failure label is the same
   	    %% as in the jump that follows -- thus it is not needed.
  +            %% Check if any of the previous instructions could also be eliminated.
  +            {Acc,St} = opt_useless_loads(Acc0, L, St0),
  +	    opt(Is, Acc, St)
  +    end;
  +opt([{test,_,{f,L}=Lbl,_}=I|[{label,L}|_]=Is], Acc0, St0) ->
  +    %% Similar to the above, except we have a fall-through rather than jump
  +    %%    Test Label Ops
  +    %%    label Label
  +    case beam_utils:is_pure_test(I) of
  +	false ->
  +	    opt(Is, [I|Acc0], label_used(Lbl, St0));
  +	true ->
  +            {Acc,St} = opt_useless_loads(Acc0, L, St0),
   	    opt(Is, Acc, St)
       end;
   opt([{test,Test0,{f,L}=Lbl,Ops}=I|[{jump,To}|Is]=Is0], Acc, St) ->
  
positive.code:     end;
  insert_fc_labels([_|_]=Is, _) -> Is.
  
  maps_append_list(K,Vs,M) ->
      case M of
          #{K:=Vs0} -> M#{K:=Vs0++Vs}; % same order as dict
  
negative.code: 	Is -> find_fixpoint(OptFun, Is)
      end.
  
  opt([{test,_,{f,L}=Lbl,_}=I|[{jump,{f,L}}|_]=Is], Acc0, St0) ->
      %% We have
      %%    Test Label Ops
      %%    jump Label
  