-- η abstraction
--------------------------------
eta, etatop :: Transform
-eta expr | is_fun expr && not (is_lam expr) = do
+-- Don't apply to expressions that are applied, since that would cause
+-- us to apply to our own result indefinitely.
+eta (AppFirst:_) expr = return expr
+-- Also don't apply to arguments, since this can cause loops with
+-- funextract. This isn't the proper solution, but due to an
+-- implementation bug in notappargs, this is how it used to work so far.
+eta (AppSecond:_) expr = return expr
+eta c expr | is_fun expr && not (is_lam expr) = do
let arg_ty = (fst . Type.splitFunTy . CoreUtils.exprType) expr
id <- Trans.lift $ mkInternalVar "param" arg_ty
change (Lam id (App expr (Var id)))
-- Leave all other expressions unchanged
-eta e = return e
-etatop = notappargs ("eta", eta)
+eta c e = return e
+etatop = everywhere ("eta", eta)
--------------------------------
-- β-reduction
beta, betatop :: Transform
-- Substitute arg for x in expr. For value lambda's, also clone before
-- substitution.
-beta (App (Lam x expr) arg) | CoreSyn.isTyVar x = setChanged >> substitute x arg expr
- | otherwise = setChanged >> substitute_clone x arg expr
+beta c (App (Lam x expr) arg) | CoreSyn.isTyVar x = setChanged >> substitute x arg c expr
+ | otherwise = setChanged >> substitute_clone x arg c expr
-- Propagate the application into the let
-beta (App (Let binds expr) arg) = change $ Let binds (App expr arg)
+beta c (App (Let binds expr) arg) = change $ Let binds (App expr arg)
-- Propagate the application into each of the alternatives
-beta (App (Case scrut b ty alts) arg) = change $ Case scrut b ty' alts'
+beta c (App (Case scrut b ty alts) arg) = change $ Case scrut b ty' alts'
where
alts' = map (\(con, bndrs, expr) -> (con, bndrs, (App expr arg))) alts
ty' = CoreUtils.applyTypeToArg ty arg
-- Leave all other expressions unchanged
-beta expr = return expr
+beta c expr = return expr
-- Perform this transform everywhere
betatop = everywhere ("beta", beta)
--------------------------------
-- Try to move casts as much downward as possible.
castprop, castproptop :: Transform
-castprop (Cast (Let binds expr) ty) = change $ Let binds (Cast expr ty)
-castprop expr@(Cast (Case scrut b _ alts) ty) = change (Case scrut b ty alts')
+castprop c (Cast (Let binds expr) ty) = change $ Let binds (Cast expr ty)
+castprop c expr@(Cast (Case scrut b _ alts) ty) = change (Case scrut b ty alts')
where
alts' = map (\(con, bndrs, expr) -> (con, bndrs, (Cast expr ty))) alts
-- Leave all other expressions unchanged
-castprop expr = return expr
+castprop c expr = return expr
-- Perform this transform everywhere
castproptop = everywhere ("castprop", castprop)
-- perhaps for others as well.
--------------------------------
castsimpl, castsimpltop :: Transform
-castsimpl expr@(Cast val ty) = do
+castsimpl c expr@(Cast val ty) = do
-- Don't extract values that are already simpl
local_var <- Trans.lift $ is_local_var val
-- Don't extract values that are not representable, to prevent loops with
else
return expr
-- Leave all other expressions unchanged
-castsimpl expr = return expr
+castsimpl c expr = return expr
-- Perform this transform everywhere
castsimpltop = everywhere ("castsimpl", castsimpl)
lambdasimpl, lambdasimpltop :: Transform
-- Don't simplify a lambda that evaluates to let, since this is already
-- normal form (and would cause infinite loops).
-lambdasimpl expr@(Lam _ (Let _ _)) = return expr
+lambdasimpl c expr@(Lam _ (Let _ _)) = return expr
-- Put the of a lambda in its own binding, but not when the expression is
-- already a local variable, or not representable (to prevent loops with
-- inlinenonrep).
-lambdasimpl expr@(Lam bndr res) = do
+lambdasimpl c expr@(Lam bndr res) = do
repr <- isRepr res
local_var <- Trans.lift $ is_local_var res
if not local_var && repr
return expr
-- Leave all other expressions unchanged
-lambdasimpl expr = return expr
+lambdasimpl c expr = return expr
-- Perform this transform everywhere
lambdasimpltop = everywhere ("lambdasimpl", lambdasimpl)
-- let derecursification
--------------------------------
letderec, letderectop :: Transform
-letderec expr@(Let (Rec binds) res) = case liftable of
+letderec c expr@(Let (Rec binds) res) = case liftable of
-- Nothing is liftable, just return
[] -> return expr
-- Something can be lifted, generate a new let expression
-- single bind recursive let.
canlift (bndr, e) = not $ expr_uses_binders bndrs e
-- Leave all other expressions unchanged
-letderec expr = return expr
+letderec c expr = return expr
-- Perform this transform everywhere
letderectop = everywhere ("letderec", letderec)
letsimpl, letsimpltop :: Transform
-- Don't simplify a let that evaluates to another let, since this is already
-- normal form (and would cause infinite loops with letflat below).
-letsimpl expr@(Let _ (Let _ _)) = return expr
+letsimpl c expr@(Let _ (Let _ _)) = return expr
-- Put the "in ..." value of a let in its own binding, but not when the
-- expression is already a local variable, or not representable (to prevent loops with inlinenonrep).
-letsimpl expr@(Let binds res) = do
+letsimpl c expr@(Let binds res) = do
repr <- isRepr res
local_var <- Trans.lift $ is_local_var res
if not local_var && repr
return expr
-- Leave all other expressions unchanged
-letsimpl expr = return expr
+letsimpl c expr = return expr
-- Perform this transform everywhere
letsimpltop = everywhere ("letsimpl", letsimpl)
-- let b' = expr' in (let b = res' in res)
letflat, letflattop :: Transform
-- Turn a nonrec let that binds a let into two nested lets.
-letflat (Let (NonRec b (Let binds res')) res) =
+letflat c (Let (NonRec b (Let binds res')) res) =
change $ Let binds (Let (NonRec b res') res)
-letflat (Let (Rec binds) expr) = do
+letflat c (Let (Rec binds) expr) = do
-- Flatten each binding.
binds' <- Utils.concatM $ Monad.mapM flatbind binds
-- Return the new let. We don't use change here, since possibly nothing has
flatbind (b, Let (NonRec b' expr') expr) = change [(b, expr), (b', expr')]
flatbind (b, expr) = return [(b, expr)]
-- Leave all other expressions unchanged
-letflat expr = return expr
+letflat c expr = return expr
-- Perform this transform everywhere
letflattop = everywhere ("letflat", letflat)
--------------------------------
-- Remove empty (recursive) lets
letremove, letremovetop :: Transform
-letremove (Let (Rec []) res) = change res
+letremove c (Let (Rec []) res) = change res
-- Leave all other expressions unchanged
-letremove expr = return expr
+letremove c expr = return expr
-- Perform this transform everywhere
letremovetop = everywhere ("letremove", letremove)
-- Unused let binding removal
--------------------------------
letremoveunused, letremoveunusedtop :: Transform
-letremoveunused expr@(Let (NonRec b bound) res) = do
+letremoveunused c expr@(Let (NonRec b bound) res) = do
let used = expr_uses_binders [b] res
if used
then return expr
else change res
-letremoveunused expr@(Let (Rec binds) res) = do
+letremoveunused c expr@(Let (Rec binds) res) = do
-- Filter out all unused binds.
let binds' = filter dobind binds
-- Only set the changed flag if binds got removed
-- expressions
dobind (bndr, _) = any (expr_uses_binders [bndr]) (res:bound_exprs)
-- Leave all other expressions unchanged
-letremoveunused expr = return expr
+letremoveunused c expr = return expr
letremoveunusedtop = everywhere ("letremoveunused", letremoveunused)
{-
-- TODO: We would very much like to use GHC's CSE module for this, but that
-- doesn't track if something changed or not, so we can't use it properly.
letmerge, letmergetop :: Transform
-letmerge expr@(Let _ _) = do
+letmerge c expr@(Let _ _) = do
let (binds, res) = flattenLets expr
binds' <- domerge binds
return $ mkNonRecLets binds' res
-- Different expressions? Don't change
| otherwise = return (b2, e2)
-- Leave all other expressions unchanged
-letmerge expr = return expr
+letmerge c expr = return expr
letmergetop = everywhere ("letmerge", letmerge)
-}
-- an infinite loop in transformation. Not inlining == is really a hack,
-- but for now it keeps things working with the most common symptom of
-- this problem.
-inlinetoplevel expr@(Var f) | Name.getOccString f `elem` ["==", "/="] = return expr
+inlinetoplevel c expr@(Var f) | Name.getOccString f `elem` ["==", "/="] = return expr
-- Any system name is candidate for inlining. Never inline user-defined
-- functions, to preserve structure.
-inlinetoplevel expr@(Var f) | not $ isUserDefined f = do
+inlinetoplevel c expr@(Var f) | not $ isUserDefined f = do
body_maybe <- needsInline f
case body_maybe of
Just body -> do
-- Leave all other expressions unchanged
-inlinetoplevel expr = return expr
+inlinetoplevel c expr = return expr
inlinetopleveltop = everywhere ("inlinetoplevel", inlinetoplevel)
-- | Does the given binder need to be inlined? If so, return the body to
--------------------------------
-- Inline all top level dictionaries, so we can use them to resolve
-- class methods based on the dictionary passed.
-inlinedict expr@(Var f) | Id.isDictId f = do
+inlinedict c expr@(Var f) | Id.isDictId f = do
body_maybe <- Trans.lift $ getGlobalBind f
case body_maybe of
Nothing -> return expr
Just body -> change body
-- Leave all other expressions unchanged
-inlinedict expr = return expr
+inlinedict c expr = return expr
inlinedicttop = everywhere ("inlinedict", inlinedict)
--------------------------------
-- using $con2tag functions to translate a datacon to an int and compare
-- that with GHC.Prim.==# . Better to avoid that for now.
classopresolution, classopresolutiontop :: Transform
-classopresolution expr@(App (App (Var sel) ty) dict) | not is_builtin =
+classopresolution c expr@(App (App (Var sel) ty) dict) | not is_builtin =
case Id.isClassOpId_maybe sel of
-- Not a class op selector
Nothing -> return expr
is_builtin = elem (Name.getOccString sel) builtinIds
-- Leave all other expressions unchanged
-classopresolution expr = return expr
+classopresolution c expr = return expr
-- Perform this transform everywhere
classopresolutiontop = everywhere ("classopresolution", classopresolution)
--------------------------------
scrutsimpl,scrutsimpltop :: Transform
-- Don't touch scrutinees that are already simple
-scrutsimpl expr@(Case (Var _) _ _ _) = return expr
+scrutsimpl c expr@(Case (Var _) _ _ _) = return expr
-- Replace all other cases with a let that binds the scrutinee and a new
-- simple scrutinee, but only when the scrutinee is representable (to prevent
-- loops with inlinenonrep, though I don't think a non-representable scrutinee
-- will be supported anyway...)
-scrutsimpl expr@(Case scrut b ty alts) = do
+scrutsimpl c expr@(Case scrut b ty alts) = do
repr <- isRepr scrut
if repr
then do
else
return expr
-- Leave all other expressions unchanged
-scrutsimpl expr = return expr
+scrutsimpl c expr = return expr
-- Perform this transform everywhere
scrutsimpltop = everywhere ("scrutsimpl", scrutsimpl)
scrutbndrremove, scrutbndrremovetop :: Transform
-- If the scrutinee is already simple, and the bndr is not wild yet, replace
-- all occurences of the binder with the scrutinee variable.
-scrutbndrremove (Case (Var scrut) bndr ty alts) | bndr_used = do
+scrutbndrremove c (Case (Var scrut) bndr ty alts) | bndr_used = do
alts' <- mapM subs_bndr alts
change $ Case (Var scrut) wild ty alts'
where
is_used (_, _, expr) = expr_uses_binders [bndr] expr
bndr_used = or $ map is_used alts
subs_bndr (con, bndrs, expr) = do
- expr' <- substitute bndr (Var scrut) expr
+ expr' <- substitute bndr (Var scrut) c expr
return (con, bndrs, expr')
wild = MkCore.mkWildBinder (Id.idType bndr)
-- Leave all other expressions unchanged
-scrutbndrremove expr = return expr
+scrutbndrremove c expr = return expr
scrutbndrremovetop = everywhere ("scrutbndrremove", scrutbndrremove)
--------------------------------
-- This is already a selector case (or, if x does not appear in bndrs, a very
-- simple case statement that will be removed by caseremove below). Just leave
-- it be.
-casesimpl expr@(Case scrut b ty [(con, bndrs, Var x)]) = return expr
+casesimpl c expr@(Case scrut b ty [(con, bndrs, Var x)]) = return expr
-- Make sure that all case alternatives have only wild binders and simple
-- expressions.
-- This is done by creating a new let binding for each non-wild binder, which
-- is bound to a new simple selector case statement and for each complex
-- expression. We do this only for representable types, to prevent loops with
-- inlinenonrep.
-casesimpl expr@(Case scrut bndr ty alts) | not bndr_used = do
+casesimpl c expr@(Case scrut bndr ty alts) | not bndr_used = do
(bindingss, alts') <- (Monad.liftM unzip) $ mapM doalt alts
let bindings = concat bindingss
-- Replace the case with a let with bindings and a case
-- Don't simplify anything else
return (Nothing, expr)
-- Leave all other expressions unchanged
-casesimpl expr = return expr
+casesimpl c expr = return expr
-- Perform this transform everywhere
casesimpltop = everywhere ("casesimpl", casesimpl)
-- binders.
caseremove, caseremovetop :: Transform
-- Replace a useless case by the value of its single alternative
-caseremove (Case scrut b ty [(con, bndrs, expr)]) | not usesvars = change expr
+caseremove c (Case scrut b ty [(con, bndrs, expr)]) | not usesvars = change expr
-- Find if any of the binders are used by expr
where usesvars = (not . VarSet.isEmptyVarSet . (CoreFVs.exprSomeFreeVars (`elem` b:bndrs))) expr
-- Leave all other expressions unchanged
-caseremove expr = return expr
+caseremove c expr = return expr
-- Perform this transform everywhere
caseremovetop = everywhere ("caseremove", caseremove)
appsimpl, appsimpltop :: Transform
-- Simplify all representable arguments. Do this by introducing a new Let
-- that binds the argument and passing the new binder in the application.
-appsimpl expr@(App f arg) = do
+appsimpl c expr@(App f arg) = do
-- Check runtime representability
repr <- isRepr arg
local_var <- Trans.lift $ is_local_var arg
else -- Leave non-representable arguments unchanged
return expr
-- Leave all other expressions unchanged
-appsimpl expr = return expr
+appsimpl c expr = return expr
-- Perform this transform everywhere
appsimpltop = everywhere ("appsimpl", appsimpl)
-- Transform any application of a named function (i.e., skip applications of
-- lambda's). Also skip applications that have arguments with free type
-- variables, since we can't inline those.
-argprop expr@(App _ _) | is_var fexpr = do
+argprop c expr@(App _ _) | is_var fexpr = do
-- Find the body of the function called
body_maybe <- Trans.lift $ getGlobalBind f
case body_maybe of
-- to a new id and just pass that new id to the old function body.
return ([arg], [id], mkReferenceTo id)
-- Leave all other expressions unchanged
-argprop expr = return expr
+argprop c expr = return expr
-- Perform this transform everywhere
argproptop = everywhere ("argprop", argprop)
-- apply map to a lambda expression This will not conflict with inlinenonrep,
-- since that only inlines local let bindings, not top level bindings.
funextract, funextracttop :: Transform
-funextract expr@(App _ _) | is_var fexpr = do
+funextract c expr@(App _ _) | is_var fexpr = do
body_maybe <- Trans.lift $ getGlobalBind f
case body_maybe of
-- We don't have a function body for f, so we can perform this transform.
doarg arg = return arg
-- Leave all other expressions unchanged
-funextract expr = return expr
+funextract c expr = return expr
-- Perform this transform everywhere
funextracttop = everywhere ("funextract", funextract)
-- solution, we should probably integrate this pass with lambdasimpl and
-- letsimpl instead.
--------------------------------
-simplrestop expr@(Lam _ _) = return expr
-simplrestop expr@(Let _ _) = return expr
-simplrestop expr = do
+simplrestop c expr@(Lam _ _) = return expr
+simplrestop c expr@(Let _ _) = return expr
+simplrestop c expr = do
local_var <- Trans.lift $ is_local_var expr
-- Don't extract values that are not representable, to prevent loops with
-- inlinenonrep
projects / matthijs / master-project / cλash.git / blobdiff