mirror of
https://github.com/idris-lang/Idris2.git
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[ performance ] CSE in linear space (#1949)
This commit is contained in:
Stefan Höck
GitHub
parent
931ff85164
commit
d180bd4b8c
@ -260,10 +260,7 @@ getCompileData doLazyAnnots phase_in tm_in
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logTime "++ Fix arity" $ traverse_ fixArityDef rcns
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compiledtm <- fixArityExp !(compileExp tm)
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(cseDefs, csetm) <- logTime "++ CSE" $ do
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um <- analyzeNames rcns
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defs <- catMaybes <$> traverse (cseDef um) rcns
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pure $ (cseNewToplevelDefs um ++ defs, adjust um compiledtm)
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(cseDefs, csetm) <- logTime "++ CSE" $ cse rcns compiledtm
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namedDefs <- logTime "++ Forget names" $
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traverse getNamedDef cseDefs
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@ -316,6 +313,13 @@ compileTerm tm_in
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= do tm <- toFullNames tm_in
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fixArityExp !(compileExp tm)
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compDef : {auto c : Ref Ctxt Defs} -> Name -> Core (Maybe (Name, FC, CDef))
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compDef n = do
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defs <- get Ctxt
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Just def <- lookupCtxtExact n (gamma defs) | Nothing => pure Nothing
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let Just cexpr = compexpr def | Nothing => pure Nothing
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pure $ Just (n, location def, cexpr)
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export
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getIncCompileData : {auto c : Ref Ctxt Defs} -> (doLazyAnnots : Bool) ->
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UsePhase -> Core CompileData
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@ -326,7 +330,7 @@ getIncCompileData doLazyAnnots phase
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let ns = keys (toIR defs)
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cns <- traverse toFullNames ns
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rcns <- filterM nonErased cns
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cseDefs <- catMaybes <$> traverse (cseDef empty) rcns
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cseDefs <- catMaybes <$> traverse compDef rcns
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namedDefs <- traverse getNamedDef cseDefs
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@ -1,6 +1,5 @@
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module Compiler.CompileExpr
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import Compiler.Opts.CSE
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import Core.CaseTree
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import public Core.CompileExpr
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import Core.Context
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@ -13,14 +13,18 @@
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||| iterate over all toplevel definitions once, trying to
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||| convert every subexpression to a closed one (no free
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||| variables). Closed terms are then stored in a `SortedMap`
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||| together with their size and count.
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||| together with their size and count. In order to only use
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||| linear space w.r.t. term size, we start this analysis at the
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||| leaves and substitute closed terms with the machine generated
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||| names before analyzing parent terms.
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|||
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||| This map is then pruned: Expressions with a count of 1 are removed,
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||| as are very small terms (some experiments showed, that a
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||| cut-off size of 5 is a good heuristic). The remaining duplicate
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||| expressions are then introduced as new zero-argument toplevel
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||| functions and replaced accordingly in all function definitions
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||| (including larger extracted subexpressions, if any).
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||| In a second step, we compare the count of each machine
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||| generated name with the count of its parent expression.
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||| If they are the same, the name is dropped and replaces with
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||| a CSE optimized version of the original expression, otherwise
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||| the name is kept and a new zero argumet function of the
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||| given name is added to the toplevel, thus eliminating the
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||| duplicate expressions.
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module Compiler.Opts.CSE
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import Core.CompileExpr
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@ -44,38 +48,37 @@ public export
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UsageMap : Type
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UsageMap = SortedMap (Integer, CExp []) (Name, Integer)
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--------------------------------------------------------------------------------
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-- Size of Expressions
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--------------------------------------------------------------------------------
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||| Number of appearances of a closed expression.
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|||
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||| `Once` : The expression occurs exactly once.
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||| `Many` : The expression occurs more than once.
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||| `C n` : The expression has been counted `n` times
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||| but we will have to compare this value
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||| with the number of occurences of its parent
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||| expression to decide whether it occured
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||| only once or several times.
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|||
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public export
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data Count = Once | Many | C Integer
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mutual
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-- comparison for `Nat` is (or used to be?) O(n),
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-- therefore, we use `Integer`
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size : CExp ns -> Integer
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size (CLocal _ _) = 1
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size (CRef _ _) = 1
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size (CLam _ _ y) = size y + 1
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size (CLet _ _ _ y z) = size y + size z + 1
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size (CApp _ _ xs) = sum (map size xs) + 1
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size (CCon _ _ _ _ xs) = sum (map size xs) + 1
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size (COp _ _ xs) = sum (map size xs) + 1
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size (CExtPrim _ _ xs) = sum (map size xs) + 1
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size (CForce _ _ y) = size y + 1
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size (CDelay _ _ y) = size y + 1
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size (CPrimVal _ _) = 1
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size (CErased _) = 1
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size (CCrash _ _) = 1
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size (CConCase _ sc xs x) =
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size sc + sum (map sizeConAlt xs) + sum (map size x) + 1
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Show Count where
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show Once = "Once"
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show Many = "Many"
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show (C n) = "C " ++ show n
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size (CConstCase _ sc xs x) =
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size sc + sum (map sizeConstAlt xs) + sum (map size x) + 1
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||| After common subexpression analysis we get a mapping
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||| from `Name`s to the closed expressions they replace.
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||| We use this mapping for substituting the names back
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||| to the corresponding expressions, if and only if
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||| the expression appears only in one place.
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public export
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ReplaceMap : Type
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ReplaceMap = SortedMap Name (CExp [], Count)
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sizeConAlt : CConAlt ns -> Integer
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sizeConAlt (MkConAlt _ _ _ _ z) = 1 + size z
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sizeConstAlt : CConstAlt ns -> Integer
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sizeConstAlt (MkConstAlt _ y) = 1 + size y
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toReplaceMap : UsageMap -> ReplaceMap
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toReplaceMap = SortedMap.fromList
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. map (\((_,exp),(n,c)) => (n, (exp, C c)))
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. SortedMap.toList
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--------------------------------------------------------------------------------
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-- State
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@ -88,24 +91,24 @@ record St where
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map : UsageMap
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idx : Int
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-- adds a new closed expression to the `UsageMap`
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-- returning the actual count of occurences.
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-- very small expressions are being ignored.
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store : Ref Sts St => CExp [] -> Core Integer
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store exp =
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let sz = size exp
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in if sz < 5
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then pure 0
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else do
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(MkSt map idx) <- get Sts
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-- Adds a new closed expression to the `UsageMap`
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-- returning a new machine generated name to be used
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-- if the expression should be lifted to the toplevel.
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-- Very small expressions are being ignored.
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store : Ref Sts St => Integer -> CExp [] -> Core (Maybe Name)
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store sz exp =
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if sz < 5
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then pure Nothing
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else do
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(MkSt map idx) <- get Sts
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(name,count,idx2) <-
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case lookup (sz,exp) map of
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Just (nm,cnt) => pure (nm, cnt+1, idx)
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Nothing => pure (MN "csegen" idx, 1, idx + 1)
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(name,count,idx2) <-
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case lookup (sz,exp) map of
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Just (nm,cnt) => pure (nm, cnt+1, idx)
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Nothing => pure (MN "csegen" idx, 1, idx + 1)
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put Sts $ MkSt (insert (sz,exp) (name, count) map) idx2
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pure count
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put Sts $ MkSt (insert (sz,exp) (name, count) map) idx2
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pure (Just name)
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--------------------------------------------------------------------------------
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-- Strengthening of Expressions
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@ -170,22 +173,18 @@ mutual
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--------------------------------------------------------------------------------
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mutual
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-- Tries to convert an expression to a closed term (`CExp []`).
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-- If this is successful, the expression's number of occurences
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-- is increased by one, otherwise, its subexpressions are analyzed
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-- in a similar manner.
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-- Tries to convert an expression and its
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-- sub-expression to closed terms (`CExp []`).
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-- Every occurence of a closed term will be replaced by
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-- a machine generated name and its count in the `UsageMap`
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-- will be increased by one.
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--
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-- We have to be careful here not to count subexpressions too
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-- often. For instance, consider a case of `outerExp (innerExp)`,
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-- where both `outerExp` and `innerExp` are closed terms. `innerExp`
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-- should be added to the set of extracted subexpressions, if
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-- and only if it appears somewhere else in the code,
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-- unrelated to `outerExp`. We must
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-- therefore make sure to analyze subexpressions of closed terms
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-- exactly once for each closed term, otherwise they might
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-- be counted as additional common subexpressions although they are not.
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-- Because we start at the leafs and substitute all closed
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-- expressions with machine generated names, we have to
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-- keep track of the original expression's size, which
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-- is returned in addition to the adjusted expressions.
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export
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analyze : Ref Sts St => CExp ns -> Core ()
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analyze : Ref Sts St => CExp ns -> Core (Integer, CExp ns)
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-- We ignore prim ops here, since moving them to the toplevel
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-- might interfere with other optimizations, for instance
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@ -199,159 +198,291 @@ mutual
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analyze c@(CForce _ _ _) = analyzeSubExp c
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analyze c@(CDelay _ _ _) = analyzeSubExp c
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analyze exp = case dropEnv {pre = []} exp of
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Just e0 => do
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count <- store e0
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-- only analyze subexpressions of closed terms once
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when (count == 1) $ analyzeSubExp exp
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Nothing => analyzeSubExp exp
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analyze exp = do
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(sze, exp') <- analyzeSubExp exp
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case dropEnv {pre = []} exp' of
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Just e0 => do
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Just nm <- store sze e0
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| Nothing => pure (sze, exp')
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pure (sze, CRef EmptyFC nm)
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Nothing => pure (sze, exp')
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analyzeSubExp : Ref Sts St => CExp ns -> Core ()
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analyzeSubExp (CLocal _ _) = pure ()
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analyzeSubExp (CRef _ _) = pure ()
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analyzeSubExp (CLam _ _ y) = analyze y
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analyzeSubExp (CLet _ _ _ y z) = analyze y >> analyze z
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analyzeSubExp (CApp fc x xs) = analyze x >> traverse_ analyze xs
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analyzeSubExp (CCon _ _ _ _ []) = pure ()
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analyzeSubExp (CCon _ _ _ _ xs) = traverse_ analyze xs
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analyzeSubExp (COp _ _ xs) = ignore $ traverseVect analyze xs
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analyzeSubExp (CExtPrim _ _ xs) = traverse_ analyze xs
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analyzeSubExp (CForce _ _ y) = analyze y
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analyzeSubExp (CDelay _ _ y) = analyze y
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analyzeSubExp (CConCase _ sc xs x) =
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analyze sc >>
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traverse_ analyzeConAlt xs >>
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ignore (traverseOpt analyze x)
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analyzeList : Ref Sts St => List (CExp ns) -> Core (Integer, List (CExp ns))
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analyzeList es = do
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(sizes, exps) <- unzip <$> traverse analyze es
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pure (sum sizes, exps)
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analyzeSubExp (CConstCase _ sc xs x) =
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analyze sc >>
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traverse_ analyzeConstAlt xs >>
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ignore (traverseOpt analyze x)
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analyzeMaybe : Ref Sts St => Maybe (CExp ns) -> Core (Integer, Maybe (CExp ns))
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analyzeMaybe Nothing = pure (0, Nothing)
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analyzeMaybe (Just e) = do
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(se,e') <- analyze e
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pure (se, Just e')
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analyzeSubExp (CPrimVal _ _) = pure ()
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analyzeSubExp (CErased _) = pure ()
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analyzeSubExp (CCrash _ _) = pure ()
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analyzeVect : Ref Sts St => Vect n (CExp ns) -> Core (Integer, Vect n (CExp ns))
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analyzeVect es = do
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(sizes, exps) <- unzip <$> traverseVect analyze es
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pure (sum sizes, exps)
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analyzeConAlt : { auto c : Ref Sts St } -> CConAlt ns -> Core ()
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analyzeConAlt (MkConAlt _ _ _ _ z) = analyze z
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analyzeConstAlt : Ref Sts St => CConstAlt ns -> Core ()
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analyzeConstAlt (MkConstAlt _ y) = analyze y
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analyzeSubExp : Ref Sts St => CExp ns -> Core (Integer, CExp ns)
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analyzeSubExp e@(CLocal _ _) = pure (1, e)
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analyzeSubExp e@(CRef _ _) = pure (1, e)
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analyzeSubExp (CLam f n y) = do
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(sy, y') <- analyze y
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pure (sy + 1, CLam f n y')
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analyzeDef : Ref Sts St => CDef -> Core ()
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analyzeDef (MkFun args x) = analyze x
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analyzeDef (MkCon _ _ _) = pure ()
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analyzeDef (MkForeign _ _ _) = pure ()
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analyzeDef (MkError _) = pure ()
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analyzeSubExp (CLet f n i y z) = do
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(sy, y') <- analyze y
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(sz, z') <- analyze z
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pure (sy + sz + 1, CLet f n i y' z')
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analyzeName : Ref Sts St => Ref Ctxt Defs => Name -> Core ()
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analyzeSubExp (CApp fc x xs) = do
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(sx, x') <- analyze x
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(sxs, xs') <- analyzeList xs
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pure (sx + sxs + 1, CApp fc x' xs')
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analyzeSubExp (CCon f n c t xs) = do
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(sxs, xs') <- analyzeList xs
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pure (sxs + 1, CCon f n c t xs')
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analyzeSubExp (COp f n xs) = do
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(sxs, xs') <- analyzeVect xs
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pure (sxs + 1, COp f n xs')
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analyzeSubExp (CExtPrim f n xs) = do
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(sxs, xs') <- analyzeList xs
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pure (sxs + 1, CExtPrim f n xs')
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analyzeSubExp (CForce f r y) = do
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(sy, y') <- analyze y
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pure (sy + 1, CForce f r y')
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analyzeSubExp (CDelay f r y) = do
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(sy, y') <- analyze y
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pure (sy + 1, CDelay f r y')
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analyzeSubExp (CConCase f sc xs x) = do
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(ssc, sc') <- analyze sc
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(sxs, xs') <- unzip <$> traverse analyzeConAlt xs
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(sx, x') <- analyzeMaybe x
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pure (ssc + sum sxs + sx + 1, CConCase f sc' xs' x')
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analyzeSubExp (CConstCase f sc xs x) = do
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(ssc, sc') <- analyze sc
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(sxs, xs') <- unzip <$> traverse analyzeConstAlt xs
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(sx, x') <- analyzeMaybe x
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pure (ssc + sum sxs + sx + 1, CConstCase f sc' xs' x')
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analyzeSubExp c@(CPrimVal _ _) = pure (1, c)
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analyzeSubExp c@(CErased _) = pure (1, c)
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analyzeSubExp c@(CCrash _ _) = pure (1, c)
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analyzeConAlt : { auto c : Ref Sts St }
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-> CConAlt ns
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-> Core (Integer, CConAlt ns)
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analyzeConAlt (MkConAlt n c t as z) = do
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(sz, z') <- analyze z
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pure (sz + 1, MkConAlt n c t as z')
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analyzeConstAlt : Ref Sts St => CConstAlt ns -> Core (Integer, CConstAlt ns)
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analyzeConstAlt (MkConstAlt c y) = do
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(sy, y') <- analyze y
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pure (sy + 1, MkConstAlt c y')
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analyzeDef : Ref Sts St => CDef -> Core CDef
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analyzeDef (MkFun args x) = MkFun args . snd <$> analyze x
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analyzeDef d@(MkCon _ _ _) = pure d
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analyzeDef d@(MkForeign _ _ _) = pure d
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analyzeDef d@(MkError _) = pure d
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analyzeName : Ref Sts St
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=> Ref Ctxt Defs
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=> Name
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-> Core (Maybe (Name, FC, CDef))
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analyzeName fn = do
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defs <- get Ctxt
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Just def <- lookupCtxtExact fn (gamma defs)
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| Nothing => pure ()
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| Nothing => pure Nothing
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let Just cexp = compexpr def
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| Nothing => pure ()
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analyzeDef cexp
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||| Generates a `UsageMap` (a mapping from closed terms
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||| to their number of occurences plus newly generated
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||| name in case they will be lifted to the toplevel)
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export
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analyzeNames : Ref Ctxt Defs => List Name -> Core UsageMap
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analyzeNames cns = do
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log "compiler.cse" 10 $ "Analysing " ++ show (length cns) ++ " names"
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s <- newRef Sts $ MkSt empty 0
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traverse_ analyzeName cns
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MkSt res _ <- get Sts
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let filtered = reverse
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. sortBy (comparing $ snd . snd)
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. filter ((> 1) . snd . snd)
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$ SortedMap.toList res
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log "compiler.cse" 10 $ unlines $
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"Selected the following definitions:"
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:: map (\((sz,_),(name,cnt)) =>
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show name ++
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": count " ++ show cnt ++
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", size " ++ show sz
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) filtered
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pure $ fromList filtered
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| Nothing => pure Nothing
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cexp' <- analyzeDef cexp
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pure $ Just (fn, location def, cexp')
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--------------------------------------------------------------------------------
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-- Adjusting Expressions
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-- Replacing Expressions
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--------------------------------------------------------------------------------
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mutual
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export
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adjust : UsageMap -> CExp ns -> CExp ns
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adjust um exp = case dropEnv {pre = []} exp of
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Nothing => adjustSubExp um exp
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Just e0 => case lookup (size e0, e0) um of
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Just (nm,_) => CApp EmptyFC (CRef EmptyFC nm) []
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Nothing => adjustSubExp um exp
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-- During the analysis step, we replaced every closed
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-- expression with a machine generated name. We only
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-- want to keep these substitutions, if a closed term
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-- appears in several distinct locations in the code.
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--
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-- We therefore check for each machine generated name, if
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-- the corresponding closed term has a count > 1. If that's
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-- not the case, the machine generated name will be dropped
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-- and replaces with the CSE-optimized original term.
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--
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-- However, during the analysis step, we might get counts > 1
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-- for expressions that still are used only once.
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-- Consider the following situation:
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--
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-- fun1 = exp1(exp2(exp3))
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-- fun2 = exp4(exp2(exp3))
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--
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-- In the example above, `exp2` is a proper common subexpression
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-- that should be lifted to the toplevel, but exp3 is not, although
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-- it will also get a count of 2 in the `UsageMap`.
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-- We therefore compare the count of each child expression
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-- with the count of their parent expression, lifting
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-- a child only if it was counted mor often than its parent.
|
||||
replaceRef : Ref ReplaceMap ReplaceMap
|
||||
=> Ref Ctxt Defs
|
||||
=> (parentCount : Integer)
|
||||
-> FC
|
||||
-> Name
|
||||
-> Core (CExp ns)
|
||||
replaceRef pc fc n = do
|
||||
log "compiler.cse" 10 $ "Trying to replace " ++ show n ++ ": "
|
||||
res <- lookup n <$> get ReplaceMap
|
||||
case res of
|
||||
-- not a name generated during CSE
|
||||
Nothing => do
|
||||
log "compiler.cse" 10 $ " not a name generated durin CSE"
|
||||
pure (CRef fc n)
|
||||
|
||||
adjustSubExp : UsageMap -> CExp ns -> CExp ns
|
||||
adjustSubExp um e@(CLocal _ _) = e
|
||||
adjustSubExp um e@(CRef _ _) = e
|
||||
adjustSubExp um e@(CPrimVal _ _) = e
|
||||
adjustSubExp um e@(CErased _) = e
|
||||
adjustSubExp um e@(CCrash _ _) = e
|
||||
adjustSubExp um (CLam fc x y) = CLam fc x $ adjust um y
|
||||
adjustSubExp um (CLet fc x inlineOK y z) =
|
||||
CLet fc x inlineOK (adjust um y) (adjust um z)
|
||||
-- Expression count has already been checked and occurs
|
||||
-- several times. Replace it with the machine generated name.
|
||||
Just (exp, Many) => do
|
||||
log "compiler.cse" 10 $ " already replaced: Occurs many times"
|
||||
pure (CApp EmptyFC (CRef fc n) [])
|
||||
|
||||
adjustSubExp um (CApp fc x xs) =
|
||||
CApp fc (adjust um x) (map (adjust um) xs)
|
||||
|
||||
adjustSubExp um (CCon fc x y tag xs) =
|
||||
CCon fc x y tag $ map (adjust um) xs
|
||||
-- Expression count has already been checked and occurs
|
||||
-- only once. Substitute the machine generated name with
|
||||
-- the original (but CSE optimized) exp
|
||||
Just (exp, Once) => do
|
||||
log "compiler.cse" 10 $ " already replaced: Occurs many times"
|
||||
pure (embed exp)
|
||||
|
||||
adjustSubExp um (COp fc x xs) = COp fc x $ map (adjust um) xs
|
||||
-- Expression count has not yet been compared with the
|
||||
-- parent count. Do this now.
|
||||
Just (exp, C c) => do
|
||||
log "compiler.cse" 10 $ " expression of unknown quantity ("
|
||||
++ show c
|
||||
++ " occurences)"
|
||||
-- We first have to replace all child expressions.
|
||||
exp' <- replaceExp c exp
|
||||
if c > pc
|
||||
-- This is a common subexpression. We set its count to `Many`
|
||||
-- and replace it with the machine generated name.
|
||||
then do
|
||||
log "compiler.cse" 10 $ show n ++ " assigned quantity \"Many\""
|
||||
update ReplaceMap (insert n (exp', Many))
|
||||
pure (CApp EmptyFC (CRef fc n) [])
|
||||
|
||||
adjustSubExp um (CExtPrim fc p xs) = CExtPrim fc p $ map (adjust um) xs
|
||||
-- This expression occurs only once. We set its count to `Once`
|
||||
-- and keep it.
|
||||
else do
|
||||
log "compiler.cse" 10 $ show n ++ " assigned quantity \"Once\""
|
||||
update ReplaceMap (insert n (exp', Once))
|
||||
pure (embed exp')
|
||||
|
||||
adjustSubExp um (CForce fc x y) = CForce fc x $ adjust um y
|
||||
replaceExp : Ref ReplaceMap ReplaceMap
|
||||
=> Ref Ctxt Defs
|
||||
=> (parentCount : Integer)
|
||||
-> CExp ns
|
||||
-> Core (CExp ns)
|
||||
replaceExp _ e@(CLocal _ _) = pure e
|
||||
replaceExp pc (CRef f n) = replaceRef pc f n
|
||||
replaceExp pc (CLam f n y) = CLam f n <$> replaceExp pc y
|
||||
replaceExp pc (CLet f n i y z) =
|
||||
CLet f n i <$> replaceExp pc y <*> replaceExp pc z
|
||||
replaceExp pc (CApp f x xs) =
|
||||
CApp f <$> replaceExp pc x <*> traverse (replaceExp pc) xs
|
||||
replaceExp pc (CCon f n c t xs) =
|
||||
CCon f n c t <$> traverse (replaceExp pc) xs
|
||||
replaceExp pc (COp f n xs) =
|
||||
COp f n <$> traverseVect (replaceExp pc) xs
|
||||
replaceExp pc (CExtPrim f n xs) =
|
||||
CExtPrim f n <$> traverse (replaceExp pc) xs
|
||||
replaceExp pc (CForce f r y) =
|
||||
CForce f r <$> replaceExp pc y
|
||||
replaceExp pc (CDelay f r y) =
|
||||
CDelay f r <$> replaceExp pc y
|
||||
replaceExp pc (CConCase f sc xs x) =
|
||||
CConCase f <$>
|
||||
replaceExp pc sc <*>
|
||||
traverse (replaceConAlt pc) xs <*>
|
||||
traverseOpt (replaceExp pc) x
|
||||
|
||||
adjustSubExp um (CDelay fc x y) = CDelay fc x $ adjust um y
|
||||
replaceExp pc (CConstCase f sc xs x) = do
|
||||
CConstCase f <$>
|
||||
replaceExp pc sc <*>
|
||||
traverse (replaceConstAlt pc) xs <*>
|
||||
traverseOpt (replaceExp pc) x
|
||||
|
||||
adjustSubExp um (CConCase fc sc xs x) =
|
||||
CConCase fc (adjust um sc) (map (adjustConAlt um) xs) (map (adjust um) x)
|
||||
replaceExp _ c@(CPrimVal _ _) = pure c
|
||||
replaceExp _ c@(CErased _) = pure c
|
||||
replaceExp _ c@(CCrash _ _) = pure c
|
||||
|
||||
adjustSubExp um (CConstCase fc sc xs x) =
|
||||
CConstCase fc (adjust um sc) (map (adjustConstAlt um) xs) (map (adjust um) x)
|
||||
replaceConAlt : Ref ReplaceMap ReplaceMap
|
||||
=> Ref Ctxt Defs
|
||||
=> (parentCount : Integer)
|
||||
-> CConAlt ns
|
||||
-> Core (CConAlt ns)
|
||||
replaceConAlt pc (MkConAlt n c t as z) =
|
||||
MkConAlt n c t as <$> replaceExp pc z
|
||||
|
||||
adjustConAlt : UsageMap -> CConAlt ns -> CConAlt ns
|
||||
adjustConAlt um (MkConAlt x y tag args z) =
|
||||
MkConAlt x y tag args $ adjust um z
|
||||
replaceConstAlt : Ref ReplaceMap ReplaceMap
|
||||
=> Ref Ctxt Defs
|
||||
=> (parentCount : Integer)
|
||||
-> CConstAlt ns
|
||||
-> Core (CConstAlt ns)
|
||||
replaceConstAlt pc (MkConstAlt c y) =
|
||||
MkConstAlt c <$> replaceExp pc y
|
||||
|
||||
adjustConstAlt : UsageMap -> CConstAlt ns -> CConstAlt ns
|
||||
adjustConstAlt um (MkConstAlt x y) = MkConstAlt x $ adjust um y
|
||||
replaceDef : Ref ReplaceMap ReplaceMap
|
||||
=> Ref Ctxt Defs
|
||||
=> (Name, FC, CDef)
|
||||
-> Core (Name, FC, CDef)
|
||||
replaceDef (n, fc, MkFun args x) =
|
||||
(\x' => (n, fc, MkFun args x')) <$> replaceExp 1 x
|
||||
replaceDef (n, fc, d@(MkCon _ _ _)) = pure (n, fc, d)
|
||||
replaceDef (n, fc, d@(MkForeign _ _ _)) = pure (n, fc, d)
|
||||
replaceDef (n, fc, d@(MkError _)) = pure (n, fc, d)
|
||||
|
||||
||| Converts occurences of common subexpressions in toplevel
|
||||
||| definitions to invocations of the corresponding
|
||||
||| (newly introduced) zero-argument toplevel functions.
|
||||
newToplevelDefs : ReplaceMap -> List (Name, FC, CDef)
|
||||
newToplevelDefs rm = mapMaybe toDef $ SortedMap.toList rm
|
||||
where toDef : (Name,(CExp[],Count)) -> Maybe (Name, FC, CDef)
|
||||
toDef (nm,(exp,Many)) = Just (nm, EmptyFC, MkFun [] exp)
|
||||
toDef _ = Nothing
|
||||
|
||||
undefinedCount : (Name, (CExp [], Count)) -> Bool
|
||||
undefinedCount (_, _, Once) = False
|
||||
undefinedCount (_, _, Many) = False
|
||||
undefinedCount (_, _, C x) = True
|
||||
|
||||
||| Runs the CSE alorithm on all provided names and
|
||||
||| the given main expression.
|
||||
export
|
||||
adjustDef : UsageMap -> CDef -> CDef
|
||||
adjustDef um (MkFun args x) = MkFun args $ adjust um x
|
||||
adjustDef um d@(MkCon _ _ _) = d
|
||||
adjustDef um d@(MkForeign _ _ _) = d
|
||||
adjustDef um d@(MkError _) = d
|
||||
|
||||
export
|
||||
cseDef : {auto c : Ref Ctxt Defs}
|
||||
-> UsageMap
|
||||
-> Name
|
||||
-> Core (Maybe (Name, FC, CDef))
|
||||
cseDef um n = do
|
||||
defs <- get Ctxt
|
||||
Just def <- lookupCtxtExact n (gamma defs) | Nothing => pure Nothing
|
||||
let Just cexpr = compexpr def | Nothing => pure Nothing
|
||||
pure $ Just (n, location def, adjustDef um cexpr)
|
||||
|
||||
export
|
||||
cseNewToplevelDefs : UsageMap -> List (Name, FC, CDef)
|
||||
cseNewToplevelDefs um = map toDef $ SortedMap.toList um
|
||||
where toDef : ((Integer, CExp[]),(Name,Integer)) -> (Name, FC, CDef)
|
||||
toDef ((_,exp),(nm,_)) =
|
||||
(nm, EmptyFC, MkFun [] $ adjustSubExp um exp)
|
||||
cse : Ref Ctxt Defs
|
||||
=> (definitionNames : List Name)
|
||||
-> (mainExpr : CExp ns)
|
||||
-> Core (List (Name, FC, CDef), CExp ns)
|
||||
cse defs me = do
|
||||
log "compiler.cse" 10 $ "Analysing " ++ show (length defs) ++ " names"
|
||||
s <- newRef Sts $ MkSt empty 0
|
||||
analyzedDefs <- mapMaybe id <$> traverse analyzeName defs
|
||||
MkSt um _ <- get Sts
|
||||
srep <- newRef ReplaceMap $ toReplaceMap um
|
||||
replacedDefs <- traverse replaceDef analyzedDefs
|
||||
replacedMain <- replaceExp 1 me
|
||||
replaceMap <- get ReplaceMap
|
||||
let filtered = SortedMap.toList replaceMap
|
||||
log "compiler.cse" 10 $ unlines $
|
||||
"Found the following unadjusted subexpressions:"
|
||||
:: map (\(name,(_,cnt)) =>
|
||||
show name ++ ": count " ++ show cnt
|
||||
) filtered
|
||||
pure (newToplevelDefs replaceMap ++ replacedDefs, replacedMain)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user