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diff --git a/lib/hipe/regalloc/hipe_spillcost.erl b/lib/hipe/regalloc/hipe_spillcost.erl
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+++ b/lib/hipe/regalloc/hipe_spillcost.erl
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+%% -*- erlang-indent-level: 2 -*-
+%%
+%% %CopyrightBegin%
+%% 
+%% Copyright Ericsson AB 2001-2009. All Rights Reserved.
+%% 
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%% 
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%% 
+%% %CopyrightEnd%
+%%
+
+-module(hipe_spillcost).
+
+-export([new/1,
+	 inc_costs/2,
+	 ref_in_bb/2,
+	 spill_cost/2]).
+%% The following is exported only for debugging purposes.
+-ifdef(DEBUG_PRINTOUTS).
+-export([nr_of_use/2]).
+-endif.
+
+%%----------------------------------------------------------------------------
+
+-include("hipe_spillcost.hrl").
+
+%%----------------------------------------------------------------------------
+
+-spec new(non_neg_integer()) -> #spill_cost{}.
+
+new(NrTemps) ->
+  #spill_cost{uses = hipe_bifs:array(NrTemps, 0),
+	      bb_uses = hipe_bifs:array(NrTemps, 0)}.
+
+%%----------------------------------------------------------------------------
+%% Function:    inc_costs
+%%
+%% Description: Registers usage of a list of temporaries (for spill_cost)
+%%----------------------------------------------------------------------------
+
+-spec inc_costs([non_neg_integer()], #spill_cost{}) -> #spill_cost{}.
+
+inc_costs(Temps, SC) ->
+  Uses = SC#spill_cost.uses,
+  lists:foreach(fun (T) -> inc_use(T, Uses) end, Temps),
+  SC. % updated via side-effects
+
+inc_use(Temp, Uses) ->
+  hipe_bifs:array_update(Uses, Temp, get_uses(Temp, Uses) + 1).
+
+nr_of_use(Temp, SC) ->
+  get_uses(Temp, SC#spill_cost.uses).
+
+get_uses(Temp, Uses) ->
+  hipe_bifs:array_sub(Uses, Temp).
+
+%%----------------------------------------------------------------------------
+%% Function:    ref_in_bb
+%%
+%% Description: Registers that a set of temporaries are used in one basic
+%%              block; should be done exactly once per basic block
+%%----------------------------------------------------------------------------
+
+-spec ref_in_bb([non_neg_integer()], #spill_cost{}) -> #spill_cost{}.
+
+ref_in_bb(Temps, SC) ->
+  BBUses = SC#spill_cost.bb_uses,
+  lists:foreach(fun (T) -> inc_bb_use(T, BBUses) end, Temps),
+  SC. % updated via side-effects
+
+inc_bb_use(Temp, BBUses) ->
+  hipe_bifs:array_update(BBUses, Temp, get_bb_uses(Temp, BBUses) + 1).
+
+bb_use(Temp, SC) ->
+  get_bb_uses(Temp, SC#spill_cost.bb_uses).
+
+get_bb_uses(Temp, BBUses) ->
+  hipe_bifs:array_sub(BBUses, Temp).
+
+%%----------------------------------------------------------------------------
+%% Function:    spill_cost
+%%
+%% Description: Computes a spill cost for a temporary
+%%   
+%% Returns:
+%%   Spill cost (a real number -- higher means worse to spill)
+%%----------------------------------------------------------------------------
+
+-spec spill_cost(non_neg_integer(), #spill_cost{}) -> float().
+
+spill_cost(Temp, SC) ->
+  nr_of_use(Temp, SC) / bb_use(Temp, SC).