289 lines
8.8 KiB
OCaml
289 lines
8.8 KiB
OCaml
(*
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* Copyright (c) 1997-1999 Massachusetts Institute of Technology
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* Copyright (c) 2003, 2007-14 Matteo Frigo
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* Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*)
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(*************************************************************
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* Conversion of the dag to an assignment list
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*************************************************************)
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(*
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* This function is messy. The main problem is that we want to
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* inline dag nodes conditionally, depending on how many times they
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* are used. The Right Thing to do would be to modify the
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* state monad to propagate some of the state backwards, so that
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* we know whether a given node will be used again in the future.
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* This modification is trivial in a lazy language, but it is
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* messy in a strict language like ML.
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*
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* In this implementation, we just do the obvious thing, i.e., visit
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* the dag twice, the first to count the node usages, and the second to
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* produce the output.
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*)
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open Monads.StateMonad
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open Monads.MemoMonad
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open Expr
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let fresh = Variable.make_temporary
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let node_insert x = Assoctable.insert Expr.hash x
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let node_lookup x = Assoctable.lookup Expr.hash (==) x
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let empty = Assoctable.empty
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let fetchAl =
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fetchState >>= (fun (al, _, _) -> returnM al)
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let storeAl al =
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fetchState >>= (fun (_, visited, visited') ->
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storeState (al, visited, visited'))
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let fetchVisited = fetchState >>= (fun (_, v, _) -> returnM v)
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let storeVisited visited =
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fetchState >>= (fun (al, _, visited') ->
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storeState (al, visited, visited'))
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let fetchVisited' = fetchState >>= (fun (_, _, v') -> returnM v')
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let storeVisited' visited' =
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fetchState >>= (fun (al, visited, _) ->
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storeState (al, visited, visited'))
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let lookupVisitedM' key =
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fetchVisited' >>= fun table ->
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returnM (node_lookup key table)
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let insertVisitedM' key value =
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fetchVisited' >>= fun table ->
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storeVisited' (node_insert key value table)
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let counting f x =
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fetchVisited >>= (fun v ->
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match node_lookup x v with
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Some count ->
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let incr_cnt =
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fetchVisited >>= (fun v' ->
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storeVisited (node_insert x (count + 1) v'))
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in
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begin
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match x with
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(* Uminus is always inlined. Visit child *)
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Uminus y -> f y >> incr_cnt
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| _ -> incr_cnt
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end
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| None ->
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f x >> fetchVisited >>= (fun v' ->
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storeVisited (node_insert x 1 v')))
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let with_varM v x =
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fetchAl >>= (fun al -> storeAl ((v, x) :: al)) >> returnM (Load v)
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let inlineM = returnM
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let with_tempM x = match x with
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| Load v when Variable.is_temporary v -> inlineM x (* avoid trivial moves *)
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| _ -> with_varM (fresh ()) x
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(* declare a temporary only if node is used more than once *)
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let with_temp_maybeM node x =
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fetchVisited >>= (fun v ->
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match node_lookup node v with
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Some count ->
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if (count = 1 && !Magic.inline_single) then
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inlineM x
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else
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with_tempM x
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| None ->
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failwith "with_temp_maybeM")
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type fma =
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NO_FMA
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| FMA of expr * expr * expr (* FMA (a, b, c) => a + b * c *)
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| FMS of expr * expr * expr (* FMS (a, b, c) => -a + b * c *)
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| FNMS of expr * expr * expr (* FNMS (a, b, c) => a - b * c *)
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let good_for_fma (a, b) =
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let good = function
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| NaN I -> true
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| NaN CONJ -> true
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| NaN _ -> false
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| Times(NaN _, _) -> false
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| Times(_, NaN _) -> false
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| _ -> true
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in good a && good b
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let build_fma l =
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if (not !Magic.enable_fma) then NO_FMA
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else match l with
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| [a; Uminus (Times (b, c))] when good_for_fma (b, c) -> FNMS (a, b, c)
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| [Uminus (Times (b, c)); a] when good_for_fma (b, c) -> FNMS (a, b, c)
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| [Uminus a; Times (b, c)] when good_for_fma (b, c) -> FMS (a, b, c)
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| [Times (b, c); Uminus a] when good_for_fma (b, c) -> FMS (a, b, c)
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| [a; Times (b, c)] when good_for_fma (b, c) -> FMA (a, b, c)
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| [Times (b, c); a] when good_for_fma (b, c) -> FMA (a, b, c)
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| _ -> NO_FMA
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let children_fma l = match build_fma l with
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| FMA (a, b, c) -> Some (a, b, c)
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| FMS (a, b, c) -> Some (a, b, c)
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| FNMS (a, b, c) -> Some (a, b, c)
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| NO_FMA -> None
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let rec visitM x =
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counting (function
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| Load v -> returnM ()
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| Num a -> returnM ()
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| NaN a -> returnM ()
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| Store (v, x) -> visitM x
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| Plus a -> (match children_fma a with
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None -> mapM visitM a >> returnM ()
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| Some (a, b, c) ->
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(* visit fma's arguments twice to make sure they are not inlined *)
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visitM a >> visitM a >>
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visitM b >> visitM b >>
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visitM c >> visitM c)
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| Times (a, b) -> visitM a >> visitM b
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| CTimes (a, b) -> visitM a >> visitM b
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| CTimesJ (a, b) -> visitM a >> visitM b
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| Uminus a -> visitM a)
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x
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let visit_rootsM = mapM visitM
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let rec expr_of_nodeM x =
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memoizing lookupVisitedM' insertVisitedM'
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(function x -> match x with
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| Load v ->
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if (Variable.is_temporary v) then
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inlineM (Load v)
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else if (Variable.is_locative v && !Magic.inline_loads) then
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inlineM (Load v)
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else if (Variable.is_constant v && !Magic.inline_loads_constants) then
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inlineM (Load v)
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else
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with_tempM (Load v)
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| Num a ->
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if !Magic.inline_constants then
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inlineM (Num a)
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else
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with_temp_maybeM x (Num a)
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| NaN a -> inlineM (NaN a)
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| Store (v, x) ->
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expr_of_nodeM x >>=
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(if !Magic.trivial_stores then with_tempM else inlineM) >>=
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with_varM v
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| Plus a ->
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begin
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match build_fma a with
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FMA (a, b, c) ->
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expr_of_nodeM a >>= fun a' ->
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expr_of_nodeM b >>= fun b' ->
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expr_of_nodeM c >>= fun c' ->
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with_temp_maybeM x (Plus [a'; Times (b', c')])
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| FMS (a, b, c) ->
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expr_of_nodeM a >>= fun a' ->
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expr_of_nodeM b >>= fun b' ->
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expr_of_nodeM c >>= fun c' ->
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with_temp_maybeM x
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(Plus [Times (b', c'); Uminus a'])
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| FNMS (a, b, c) ->
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expr_of_nodeM a >>= fun a' ->
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expr_of_nodeM b >>= fun b' ->
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expr_of_nodeM c >>= fun c' ->
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with_temp_maybeM x
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(Plus [a'; Uminus (Times (b', c'))])
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| NO_FMA ->
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mapM expr_of_nodeM a >>= fun a' ->
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with_temp_maybeM x (Plus a')
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end
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| CTimes (Load _ as a, b) when !Magic.generate_bytw ->
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expr_of_nodeM b >>= fun b' ->
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with_tempM (CTimes (a, b'))
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| CTimes (a, b) ->
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expr_of_nodeM a >>= fun a' ->
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expr_of_nodeM b >>= fun b' ->
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with_tempM (CTimes (a', b'))
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| CTimesJ (Load _ as a, b) when !Magic.generate_bytw ->
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expr_of_nodeM b >>= fun b' ->
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with_tempM (CTimesJ (a, b'))
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| CTimesJ (a, b) ->
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expr_of_nodeM a >>= fun a' ->
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expr_of_nodeM b >>= fun b' ->
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with_tempM (CTimesJ (a', b'))
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| Times (a, b) ->
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expr_of_nodeM a >>= fun a' ->
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expr_of_nodeM b >>= fun b' ->
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begin
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match a' with
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Num a'' when !Magic.strength_reduce_mul && Number.is_two a'' ->
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(inlineM b' >>= fun b'' ->
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with_temp_maybeM x (Plus [b''; b'']))
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| _ -> with_temp_maybeM x (Times (a', b'))
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end
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| Uminus a ->
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expr_of_nodeM a >>= fun a' ->
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inlineM (Uminus a'))
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x
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let expr_of_rootsM = mapM expr_of_nodeM
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let peek_alistM roots =
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visit_rootsM roots >> expr_of_rootsM roots >> fetchAl
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let wrap_assign (a, b) = Expr.Assign (a, b)
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let to_assignments dag =
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let () = Util.info "begin to_alist" in
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let al = List.rev (runM ([], empty, empty) peek_alistM dag) in
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let res = List.map wrap_assign al in
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let () = Util.info "end to_alist" in
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res
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(* dump alist in `dot' format *)
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let dump print alist =
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let vs v = "\"" ^ (Variable.unparse v) ^ "\"" in
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begin
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print "digraph G {\n";
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print "\tsize=\"6,6\";\n";
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(* all input nodes have the same rank *)
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print "{ rank = same;\n";
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List.iter (fun (Expr.Assign (v, x)) ->
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List.iter (fun y ->
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if (Variable.is_locative y) then print("\t" ^ (vs y) ^ ";\n"))
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(Expr.find_vars x))
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alist;
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print "}\n";
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(* all output nodes have the same rank *)
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print "{ rank = same;\n";
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List.iter (fun (Expr.Assign (v, x)) ->
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if (Variable.is_locative v) then print("\t" ^ (vs v) ^ ";\n"))
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alist;
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print "}\n";
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(* edges *)
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List.iter (fun (Expr.Assign (v, x)) ->
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List.iter (fun y -> print("\t" ^ (vs y) ^ " -> " ^ (vs v) ^ ";\n"))
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(Expr.find_vars x))
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alist;
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print "}\n";
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end
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