\section[SpecConstr]{Specialise over constructors}
\begin{code}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
module SpecConstr(
specConstrProgram
) where
import PprCore ( pprRules )
import WwLib ( mkWorkerArgs )
import DataCon ( dataConRepArity, dataConUnivTyVars )
-import Type ( Type, tyConAppArgs )
-import Coercion ( coercionKind )
-import Id ( Id, idName, idType, isDataConWorkId_maybe,
+import Coercion
+import Type hiding( substTy )
+import Id ( Id, idName, idType, isDataConWorkId_maybe, idArity,
mkUserLocal, mkSysLocal, idUnfolding, isLocalId )
-import Var ( Var )
+import Var
import VarEnv
import VarSet
-import Name ( nameOccName, nameSrcLoc )
+import Name
import Rules ( addIdSpecialisations, mkLocalRule, rulesOfBinds )
import OccName ( mkSpecOcc )
import ErrUtils ( dumpIfSet_dyn )
import DynFlags ( DynFlags(..), DynFlag(..) )
+import StaticFlags ( opt_SpecInlineJoinPoints )
import BasicTypes ( Activation(..) )
-import Maybes ( orElse, catMaybes )
+import Maybes ( orElse, catMaybes, isJust )
import Util
import List ( nubBy, partition )
import UniqSupply
import Outputable
import FastString
import UniqFM
+import MonadUtils
\end{code}
-----------------------------------------------------
return binds'
where
- go env [] = returnUs []
- go env (bind:binds) = scBind env bind `thenUs` \ (env', _, bind') ->
- go env' binds `thenUs` \ binds' ->
- returnUs (bind' : binds')
+ go _ [] = return []
+ go env (bind:binds) = do (env', _, bind') <- scBind env bind
+ binds' <- go env' binds
+ return (bind' : binds')
\end{code}
%************************************************************************
\begin{code}
-data ScEnv = SCE { sc_size :: Int, -- Size threshold
+data ScEnv = SCE { sc_size :: Maybe Int, -- Size threshold
- sc_subst :: Subst, -- Current subsitution
+ sc_subst :: Subst, -- Current substitution
+ -- Maps InIds to OutExprs
sc_how_bound :: HowBoundEnv,
-- Binds interesting non-top-level variables
- -- Look up in here *after* applying the substitution
+ -- Domain is OutVars (*after* applying the substitution)
- sc_cons :: ConstrEnv
- -- Look up in here *after* applying the substitution
+ sc_vals :: ValueEnv
+ -- Domain is OutIds (*after* applying the substitution)
+ -- Used even for top-level bindings (but not imported ones)
}
-type HowBoundEnv = VarEnv HowBound
+---------------------
+-- As we go, we apply a substitution (sc_subst) to the current term
+type InExpr = CoreExpr -- *Before* applying the subst
+
+type OutExpr = CoreExpr -- *After* applying the subst
+type OutId = Id
+type OutVar = Var
-type ConstrEnv = IdEnv ConValue
-data ConValue = CV AltCon [CoreArg]
- -- Variables known to be bound to a constructor
- -- in a particular case alternative
+---------------------
+type HowBoundEnv = VarEnv HowBound -- Domain is OutVars
+---------------------
+type ValueEnv = IdEnv Value -- Domain is OutIds
+data Value = ConVal AltCon [CoreArg] -- *Saturated* constructors
+ | LambdaVal -- Inlinable lambdas or PAPs
-instance Outputable ConValue where
- ppr (CV con args) = ppr con <+> interpp'SP args
+instance Outputable Value where
+ ppr (ConVal con args) = ppr con <+> interpp'SP args
+ ppr LambdaVal = ptext SLIT("<Lambda>")
+---------------------
+initScEnv :: DynFlags -> ScEnv
initScEnv dflags
- = SCE { sc_size = specThreshold dflags,
+ = SCE { sc_size = specConstrThreshold dflags,
sc_subst = emptySubst,
sc_how_bound = emptyVarEnv,
- sc_cons = emptyVarEnv }
+ sc_vals = emptyVarEnv }
data HowBound = RecFun -- These are the recursive functions for which
-- we seek interesting call patterns
-- Bring the quantified variables into scope
extendScInScope env qvars = env { sc_subst = extendInScopeList (sc_subst env) qvars }
-extendScSubst :: ScEnv -> [(Var,CoreArg)] -> ScEnv
-- Extend the substitution
-extendScSubst env prs = env { sc_subst = extendSubstList (sc_subst env) prs }
+extendScSubst :: ScEnv -> Var -> OutExpr -> ScEnv
+extendScSubst env var expr = env { sc_subst = extendSubst (sc_subst env) var expr }
+
+extendScSubstList :: ScEnv -> [(Var,OutExpr)] -> ScEnv
+extendScSubstList env prs = env { sc_subst = extendSubstList (sc_subst env) prs }
extendHowBound :: ScEnv -> [Var] -> HowBound -> ScEnv
extendHowBound env bndrs how_bound
where
(subst', bndr') = substBndr (sc_subst env) bndr
-extendConEnv :: ScEnv -> Id -> Maybe ConValue -> ScEnv
-extendConEnv env id Nothing = env
-extendConEnv env id (Just cv) = env { sc_cons = extendVarEnv (sc_cons env) id cv }
+extendValEnv :: ScEnv -> Id -> Maybe Value -> ScEnv
+extendValEnv env _ Nothing = env
+extendValEnv env id (Just cv) = env { sc_vals = extendVarEnv (sc_vals env) id cv }
extendCaseBndrs :: ScEnv -> CoreExpr -> Id -> AltCon -> [Var] -> ScEnv
-- When we encounter
-- case scrut of b
-- C x y -> ...
-- we want to bind b, and perhaps scrut too, to (C x y)
--- NB: Extends only the sc_cons part of the envt
+-- NB: Extends only the sc_vals part of the envt
extendCaseBndrs env scrut case_bndr con alt_bndrs
= case scrut of
- Var v -> extendConEnv env1 v cval
- other -> env1
+ Var v -> extendValEnv env1 v cval
+ _other -> env1
where
- env1 = extendConEnv env case_bndr cval
+ env1 = extendValEnv env case_bndr cval
cval = case con of
DEFAULT -> Nothing
- LitAlt lit -> Just (CV con [])
- DataAlt dc -> Just (CV con vanilla_args)
+ LitAlt {} -> Just (ConVal con [])
+ DataAlt {} -> Just (ConVal con vanilla_args)
where
vanilla_args = map Type (tyConAppArgs (idType case_bndr)) ++
varsToCoreExprs alt_bndrs
\begin{code}
data ScUsage
= SCU {
- calls :: CallEnv, -- Calls
+ scu_calls :: CallEnv, -- Calls
-- The functions are a subset of the
-- RecFuns in the ScEnv
- occs :: !(IdEnv ArgOcc) -- Information on argument occurrences
- } -- The variables are a subset of the
- -- RecArg in the ScEnv
+ scu_occs :: !(IdEnv ArgOcc) -- Information on argument occurrences
+ } -- The domain is OutIds
type CallEnv = IdEnv [Call]
-type Call = (ConstrEnv, [CoreArg])
+type Call = (ValueEnv, [CoreArg])
-- The arguments of the call, together with the
-- env giving the constructor bindings at the call site
-nullUsage = SCU { calls = emptyVarEnv, occs = emptyVarEnv }
+nullUsage :: ScUsage
+nullUsage = SCU { scu_calls = emptyVarEnv, scu_occs = emptyVarEnv }
combineCalls :: CallEnv -> CallEnv -> CallEnv
combineCalls = plusVarEnv_C (++)
-combineUsage u1 u2 = SCU { calls = combineCalls (calls u1) (calls u2),
- occs = plusVarEnv_C combineOcc (occs u1) (occs u2) }
+combineUsage :: ScUsage -> ScUsage -> ScUsage
+combineUsage u1 u2 = SCU { scu_calls = combineCalls (scu_calls u1) (scu_calls u2),
+ scu_occs = plusVarEnv_C combineOcc (scu_occs u1) (scu_occs u2) }
+combineUsages :: [ScUsage] -> ScUsage
combineUsages [] = nullUsage
combineUsages us = foldr1 combineUsage us
-lookupOcc :: ScUsage -> Var -> (ScUsage, ArgOcc)
-lookupOcc (SCU { calls = sc_calls, occs = sc_occs }) bndr
- = (SCU {calls = sc_calls, occs = delVarEnv sc_occs bndr},
+lookupOcc :: ScUsage -> OutVar -> (ScUsage, ArgOcc)
+lookupOcc (SCU { scu_calls = sc_calls, scu_occs = sc_occs }) bndr
+ = (SCU {scu_calls = sc_calls, scu_occs = delVarEnv sc_occs bndr},
lookupVarEnv sc_occs bndr `orElse` NoOcc)
-lookupOccs :: ScUsage -> [Var] -> (ScUsage, [ArgOcc])
-lookupOccs (SCU { calls = sc_calls, occs = sc_occs }) bndrs
- = (SCU {calls = sc_calls, occs = delVarEnvList sc_occs bndrs},
+lookupOccs :: ScUsage -> [OutVar] -> (ScUsage, [ArgOcc])
+lookupOccs (SCU { scu_calls = sc_calls, scu_occs = sc_occs }) bndrs
+ = (SCU {scu_calls = sc_calls, scu_occs = delVarEnvList sc_occs bndrs},
[lookupVarEnv sc_occs b `orElse` NoOcc | b <- bndrs])
data ArgOcc = NoOcc -- Doesn't occur at all; or a type argument
-- that if the thing is scrutinised anywhere then we get to see that
-- in the overall result, even if it's also used in a boxed way
-- This might be too agressive; see Note [Reboxing] Alternative 3
+combineOcc :: ArgOcc -> ArgOcc -> ArgOcc
combineOcc NoOcc occ = occ
combineOcc occ NoOcc = occ
combineOcc (ScrutOcc xs) (ScrutOcc ys) = ScrutOcc (plusUFM_C combineOccs xs ys)
-combineOcc occ (ScrutOcc ys) = ScrutOcc ys
-combineOcc (ScrutOcc xs) occ = ScrutOcc xs
+combineOcc _occ (ScrutOcc ys) = ScrutOcc ys
+combineOcc (ScrutOcc xs) _occ = ScrutOcc xs
combineOcc UnkOcc UnkOcc = UnkOcc
combineOcc _ _ = BothOcc
combineOccs :: [ArgOcc] -> [ArgOcc] -> [ArgOcc]
combineOccs xs ys = zipWithEqual "combineOccs" combineOcc xs ys
-setScrutOcc :: ScEnv -> ScUsage -> CoreExpr -> ArgOcc -> ScUsage
+setScrutOcc :: ScEnv -> ScUsage -> OutExpr -> ArgOcc -> ScUsage
-- *Overwrite* the occurrence info for the scrutinee, if the scrutinee
-- is a variable, and an interesting variable
setScrutOcc env usg (Cast e _) occ = setScrutOcc env usg e occ
setScrutOcc env usg (Note _ e) occ = setScrutOcc env usg e occ
setScrutOcc env usg (Var v) occ
- | Just RecArg <- lookupHowBound env v = usg { occs = extendVarEnv (occs usg) v occ }
+ | Just RecArg <- lookupHowBound env v = usg { scu_occs = extendVarEnv (scu_occs usg) v occ }
| otherwise = usg
-setScrutOcc env usg other occ -- Catch-all
+setScrutOcc _env usg _other _occ -- Catch-all
= usg
conArgOccs :: ArgOcc -> AltCon -> [ArgOcc]
conArgOccs (ScrutOcc fm) (DataAlt dc)
| Just pat_arg_occs <- lookupUFM fm dc
- = [UnkOcc | tv <- dataConUnivTyVars dc] ++ pat_arg_occs
+ = [UnkOcc | _ <- dataConUnivTyVars dc] ++ pat_arg_occs
-conArgOccs other con = repeat UnkOcc
+conArgOccs _other _con = repeat UnkOcc
\end{code}
%************************************************************************
creates specialised versions of functions.
\begin{code}
-scExpr :: ScEnv -> CoreExpr -> UniqSM (ScUsage, CoreExpr)
+scExpr, scExpr' :: ScEnv -> CoreExpr -> UniqSM (ScUsage, CoreExpr)
-- The unique supply is needed when we invent
-- a new name for the specialised function and its args
scExpr' env (Var v) = case scSubstId env v of
- Var v' -> returnUs (varUsage env v UnkOcc, Var v')
+ Var v' -> return (varUsage env v' UnkOcc, Var v')
e' -> scExpr (zapScSubst env) e'
-scExpr' env e@(Type t) = returnUs (nullUsage, Type (scSubstTy env t))
-scExpr' env e@(Lit l) = returnUs (nullUsage, e)
-scExpr' env (Note n e) = do { (usg,e') <- scExpr env e
- ; return (usg, Note n e') }
-scExpr' env (Cast e co) = do { (usg, e') <- scExpr env e
- ; return (usg, Cast e' (scSubstTy env co)) }
-scExpr' env (Lam b e) = do { let (env', b') = extendBndr env b
- ; (usg, e') <- scExpr env' e
- ; return (usg, Lam b' e') }
+scExpr' env (Type t) = return (nullUsage, Type (scSubstTy env t))
+scExpr' _ e@(Lit {}) = return (nullUsage, e)
+scExpr' env (Note n e) = do (usg,e') <- scExpr env e
+ return (usg, Note n e')
+scExpr' env (Cast e co) = do (usg, e') <- scExpr env e
+ return (usg, Cast e' (scSubstTy env co))
+scExpr' env e@(App _ _) = scApp env (collectArgs e)
+scExpr' env (Lam b e) = do let (env', b') = extendBndr env b
+ (usg, e') <- scExpr env' e
+ return (usg, Lam b' e')
scExpr' env (Case scrut b ty alts)
= do { (scrut_usg, scrut') <- scExpr env scrut
- ; case isConApp (sc_cons env) scrut' of
- Nothing -> sc_vanilla scrut_usg scrut'
- Just cval -> sc_con_app cval scrut'
+ ; case isValue (sc_vals env) scrut' of
+ Just (ConVal con args) -> sc_con_app con args scrut'
+ _other -> sc_vanilla scrut_usg scrut'
}
where
- sc_con_app cval@(CV con args) scrut' -- Known constructor; simplify
+ sc_con_app con args scrut' -- Known constructor; simplify
= do { let (_, bs, rhs) = findAlt con alts
- alt_env' = extendScSubst env ((b,scrut') : bs `zip` trimConArgs con args)
+ alt_env' = extendScSubstList env ((b,scrut') : bs `zip` trimConArgs con args)
; scExpr alt_env' rhs }
-
sc_vanilla scrut_usg scrut' -- Normal case
= do { let (alt_env,b') = extendBndrWith RecArg env b
-- Record RecArg for the components
; (alt_usgs, alt_occs, alts')
- <- mapAndUnzip3Us (sc_alt alt_env scrut' b') alts
+ <- mapAndUnzip3M (sc_alt alt_env scrut' b') alts
- ; let (alt_usg, b_occ) = lookupOcc (combineUsages alt_usgs) b
+ ; let (alt_usg, b_occ) = lookupOcc (combineUsages alt_usgs) b'
scrut_occ = foldr combineOcc b_occ alt_occs
scrut_usg' = setScrutOcc env scrut_usg scrut' scrut_occ
-- The combined usage of the scrutinee is given
= do { let (env1, bs') = extendBndrsWith RecArg env bs
env2 = extendCaseBndrs env1 scrut' b' con bs'
; (usg,rhs') <- scExpr env2 rhs
- ; let (usg', arg_occs) = lookupOccs usg bs
+ ; let (usg', arg_occs) = lookupOccs usg bs'
scrut_occ = case con of
DataAlt dc -> ScrutOcc (unitUFM dc arg_occs)
- other -> ScrutOcc emptyUFM
+ _ofther -> ScrutOcc emptyUFM
; return (usg', scrut_occ, (con,bs',rhs')) }
scExpr' env (Let (NonRec bndr rhs) body)
- = do { (rhs_usg, rhs_info@(_, args', rhs_body', _)) <- scRecRhs env (bndr,rhs)
- ; if null args' || isEmptyVarEnv (calls rhs_usg) then do
+ | isTyVar bndr -- Type-lets may be created by doBeta
+ = scExpr' (extendScSubst env bndr rhs) body
+ | otherwise
+ = do { let (body_env, bndr') = extendBndr env bndr
+ ; (rhs_usg, (_, args', rhs_body', _)) <- scRecRhs env (bndr',rhs)
+ ; let rhs' = mkLams args' rhs_body'
+
+ ; if not opt_SpecInlineJoinPoints || null args' || isEmptyVarEnv (scu_calls rhs_usg) then do
do { -- Vanilla case
- let rhs' = mkLams args' rhs_body'
- (body_env, bndr') = extendBndr env bndr
- body_env2 = extendConEnv body_env bndr' (isConApp (sc_cons env) rhs')
- -- Record if the RHS is a constructor
+ let body_env2 = extendValEnv body_env bndr' (isValue (sc_vals env) rhs')
+ -- Record if the RHS is a value
; (body_usg, body') <- scExpr body_env2 body
; return (body_usg `combineUsage` rhs_usg, Let (NonRec bndr' rhs') body') }
- else
+ else -- For now, just brutally inline the join point
+ do { let body_env2 = extendScSubst env bndr rhs'
+ ; scExpr body_env2 body } }
+
+
+{- Old code
do { -- Join-point case
- let (body_env, bndr') = extendBndrWith RecFun env bndr
+ let body_env2 = extendHowBound body_env [bndr'] RecFun
-- If the RHS of this 'let' contains calls
-- to recursive functions that we're trying
-- to specialise, then treat this let too
-- as one to specialise
- ; (body_usg, body') <- scExpr body_env body
+ ; (body_usg, body') <- scExpr body_env2 body
- ; (spec_usg, _, specs) <- specialise env (calls body_usg) ([], rhs_info)
+ ; (spec_usg, _, specs) <- specialise env (scu_calls body_usg) ([], rhs_info)
- ; return (body_usg { calls = calls body_usg `delVarEnv` bndr' }
+ ; return (body_usg { scu_calls = scu_calls body_usg `delVarEnv` bndr' }
`combineUsage` rhs_usg `combineUsage` spec_usg,
mkLets [NonRec b r | (b,r) <- addRules rhs_info specs] body')
- } }
+ }
+-}
scExpr' env (Let (Rec prs) body)
= do { (env', bind_usg, bind') <- scBind env (Rec prs)
; (body_usg, body') <- scExpr env' body
; return (bind_usg `combineUsage` body_usg, Let bind' body') }
-scExpr' env e@(App _ _)
- = do { let (fn, args) = collectArgs e
- ; (fn_usg, fn') <- scExpr env fn
- -- Process the function too. It's almost always a variable,
- -- but not always. In particular, if this pass follows float-in,
- -- which it may, we can get
- -- (let f = ...f... in f) arg1 arg2
- -- Also the substitution may replace a variable by a non-variable
-
- ; let fn_usg' = setScrutOcc env fn_usg fn' (ScrutOcc emptyUFM)
- -- We use setScrutOcc to record the fact that the function is called
- -- Perhaps we should check that it has at least one value arg,
- -- but currently we don't bother
-
- ; (arg_usgs, args') <- mapAndUnzipUs (scExpr env) args
- ; let call_usg = case fn' of
- Var f | Just RecFun <- lookupHowBound env f
- , not (null args) -- Not a proper call!
- -> SCU { calls = unitVarEnv f [(sc_cons env, args')],
- occs = emptyVarEnv }
- other -> nullUsage
- ; return (combineUsages arg_usgs `combineUsage` fn_usg'
- `combineUsage` call_usg,
- mkApps fn' args') }
+-----------------------------------
+scApp :: ScEnv -> (InExpr, [InExpr]) -> UniqSM (ScUsage, CoreExpr)
+
+scApp env (Var fn, args) -- Function is a variable
+ = ASSERT( not (null args) )
+ do { args_w_usgs <- mapM (scExpr env) args
+ ; let (arg_usgs, args') = unzip args_w_usgs
+ arg_usg = combineUsages arg_usgs
+ ; case scSubstId env fn of
+ fn'@(Lam {}) -> scExpr (zapScSubst env) (doBeta fn' args')
+ -- Do beta-reduction and try again
+
+ Var fn' -> return (arg_usg `combineUsage` fn_usg, mkApps (Var fn') args')
+ where
+ fn_usg = case lookupHowBound env fn' of
+ Just RecFun -> SCU { scu_calls = unitVarEnv fn' [(sc_vals env, args')],
+ scu_occs = emptyVarEnv }
+ Just RecArg -> SCU { scu_calls = emptyVarEnv,
+ scu_occs = unitVarEnv fn' (ScrutOcc emptyUFM) }
+ Nothing -> nullUsage
+
+
+ other_fn' -> return (arg_usg, mkApps other_fn' args') }
+ -- NB: doing this ignores any usage info from the substituted
+ -- function, but I don't think that matters. If it does
+ -- we can fix it.
+ where
+ doBeta :: OutExpr -> [OutExpr] -> OutExpr
+ -- ToDo: adjust for System IF
+ doBeta (Lam bndr body) (arg : args) = Let (NonRec bndr arg) (doBeta body args)
+ doBeta fn args = mkApps fn args
+
+-- The function is almost always a variable, but not always.
+-- In particular, if this pass follows float-in,
+-- which it may, we can get
+-- (let f = ...f... in f) arg1 arg2
+scApp env (other_fn, args)
+ = do { (fn_usg, fn') <- scExpr env other_fn
+ ; (arg_usgs, args') <- mapAndUnzipM (scExpr env) args
+ ; return (combineUsages arg_usgs `combineUsage` fn_usg, mkApps fn' args') }
----------------------
scBind :: ScEnv -> CoreBind -> UniqSM (ScEnv, ScUsage, CoreBind)
scBind env (Rec prs)
- | not (all (couldBeSmallEnoughToInline (sc_size env)) rhss)
+ | Just threshold <- sc_size env
+ , not (all (couldBeSmallEnoughToInline threshold) rhss)
-- No specialisation
= do { let (rhs_env,bndrs') = extendRecBndrs env bndrs
- ; (rhs_usgs, rhss') <- mapAndUnzipUs (scExpr rhs_env) rhss
+ ; (rhs_usgs, rhss') <- mapAndUnzipM (scExpr rhs_env) rhss
; return (rhs_env, combineUsages rhs_usgs, Rec (bndrs' `zip` rhss')) }
| otherwise -- Do specialisation
= do { let (rhs_env1,bndrs') = extendRecBndrs env bndrs
- rhs_env2 = extendHowBound rhs_env1 bndrs RecFun
+ rhs_env2 = extendHowBound rhs_env1 bndrs' RecFun
- ; (rhs_usgs, rhs_infos) <- mapAndUnzipUs (scRecRhs rhs_env2) (bndrs' `zip` rhss)
+ ; (rhs_usgs, rhs_infos) <- mapAndUnzipM (scRecRhs rhs_env2) (bndrs' `zip` rhss)
; let rhs_usg = combineUsages rhs_usgs
- ; (spec_usg, specs) <- spec_loop rhs_env2 (calls rhs_usg)
+ ; (spec_usg, specs) <- spec_loop rhs_env2 (scu_calls rhs_usg)
(repeat [] `zip` rhs_infos)
; let all_usg = rhs_usg `combineUsage` spec_usg
; return (rhs_env1, -- For the body of the letrec, delete the RecFun business
- all_usg { calls = calls rhs_usg `delVarEnvList` bndrs' },
+ all_usg { scu_calls = scu_calls rhs_usg `delVarEnvList` bndrs' },
Rec (concat (zipWith addRules rhs_infos specs))) }
where
(bndrs,rhss) = unzip prs
-> [([CallPat], RhsInfo)] -- One per binder
-> UniqSM (ScUsage, [[SpecInfo]]) -- One list per binder
spec_loop env all_calls rhs_stuff
- = do { (spec_usg_s, new_pats_s, specs) <- mapAndUnzip3Us (specialise env all_calls) rhs_stuff
+ = do { (spec_usg_s, new_pats_s, specs) <- mapAndUnzip3M (specialise env all_calls) rhs_stuff
; let spec_usg = combineUsages spec_usg_s
; if all null new_pats_s then
return (spec_usg, specs) else do
- { (spec_usg1, specs1) <- spec_loop env (calls spec_usg)
+ { (spec_usg1, specs1) <- spec_loop env (scu_calls spec_usg)
(zipWith add_pats new_pats_s rhs_stuff)
; return (spec_usg `combineUsage` spec_usg1, zipWith (++) specs specs1) } }
scBind env (NonRec bndr rhs)
= do { (usg, rhs') <- scExpr env rhs
- ; let (env', bndr') = extendBndr env bndr
- ; return (env', usg, NonRec bndr' rhs') }
+ ; let (env1, bndr') = extendBndr env bndr
+ env2 = extendValEnv env1 bndr' (isValue (sc_vals env) rhs')
+ ; return (env2, usg, NonRec bndr' rhs') }
----------------------
-scRecRhs :: ScEnv -> (Id,CoreExpr) -> UniqSM (ScUsage, RhsInfo)
+scRecRhs :: ScEnv -> (OutId, InExpr) -> UniqSM (ScUsage, RhsInfo)
scRecRhs env (bndr,rhs)
= do { let (arg_bndrs,body) = collectBinders rhs
(body_env, arg_bndrs') = extendBndrsWith RecArg env arg_bndrs
rules = [r | (r,_,_) <- specs]
----------------------
+varUsage :: ScEnv -> OutVar -> ArgOcc -> ScUsage
varUsage env v use
- | Just RecArg <- lookupHowBound env v = SCU { calls = emptyVarEnv,
- occs = unitVarEnv v use }
+ | Just RecArg <- lookupHowBound env v = SCU { scu_calls = emptyVarEnv
+ , scu_occs = unitVarEnv v use }
| otherwise = nullUsage
\end{code}
%************************************************************************
\begin{code}
-type RhsInfo = (Id, [Var], CoreExpr, [ArgOcc])
+type RhsInfo = (OutId, [OutVar], OutExpr, [ArgOcc])
-- Info about the *original* RHS of a binding we are specialising
-- Original binding f = \xs.body
-- Plus info about usage of arguments
-type SpecInfo = (CoreRule, Var, CoreExpr)
+type SpecInfo = (CoreRule, OutId, OutExpr)
-- One specialisation: Rule plus definition
-- text "good pats" <+> ppr pats]) $
-- return ()
- ; (spec_usgs, specs) <- mapAndUnzipUs (spec_one env fn arg_bndrs body)
+ ; (spec_usgs, specs) <- mapAndUnzipM (spec_one env fn arg_bndrs body)
(pats `zip` [length done_pats..])
; return (combineUsages spec_usgs, pats, specs) }
---------------------
spec_one :: ScEnv
- -> Id -- Function
+ -> OutId -- Function
-> [Var] -- Lambda-binders of RHS; should match patterns
-> CoreExpr -- Body of the original function
-> (([Var], [CoreArg]), Int)
spec_one env fn arg_bndrs body ((qvars, pats), rule_number)
= do { -- Specialise the body
- let spec_env = extendScSubst (extendScInScope env qvars)
- (arg_bndrs `zip` pats)
+ let spec_env = extendScSubstList (extendScInScope env qvars)
+ (arg_bndrs `zip` pats)
; (spec_usg, spec_body) <- scExpr spec_env body
-- ; pprTrace "spec_one" (ppr fn <+> vcat [text "pats" <+> ppr pats,
--- text "calls" <+> (ppr (calls spec_usg))])
+-- text "calls" <+> (ppr (scu_calls spec_usg))])
-- (return ())
-- And build the results
-- a spec_rhs of unlifted type and no args
fn_name = idName fn
- fn_loc = nameSrcLoc fn_name
+ fn_loc = nameSrcSpan fn_name
spec_occ = mkSpecOcc (nameOccName fn_name)
rule_name = mkFastString ("SC:" ++ showSDoc (ppr fn <> int rule_number))
spec_rhs = mkLams spec_lam_args spec_body
-- C a (D (f x) (g y)) ==> C p1 (D p2 p3)
argToPat :: InScopeSet -- What's in scope at the fn defn site
- -> ConstrEnv -- ConstrEnv at the call site
+ -> ValueEnv -- ValueEnv at the call site
-> CoreArg -- A call arg (or component thereof)
-> ArgOcc
-> UniqSM (Bool, CoreArg)
-- lvl7 --> (True, lvl7) if lvl7 is bound
-- somewhere further out
-argToPat in_scope con_env arg@(Type ty) arg_occ
+argToPat _in_scope _val_env arg@(Type {}) _arg_occ
= return (False, arg)
-argToPat in_scope con_env (Note n arg) arg_occ
- = argToPat in_scope con_env arg arg_occ
+argToPat in_scope val_env (Note _ arg) arg_occ
+ = argToPat in_scope val_env arg arg_occ
-- Note [Notes in call patterns]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- Ignore Notes. In particular, we want to ignore any InlineMe notes
-- ride roughshod over them all for now.
--- See Note [Notes in RULE matching] in Rules
-argToPat in_scope con_env (Let _ arg) arg_occ
- = argToPat in_scope con_env arg arg_occ
+argToPat in_scope val_env (Let _ arg) arg_occ
+ = argToPat in_scope val_env arg arg_occ
-- Look through let expressions
-- e.g. f (let v = rhs in \y -> ...v...)
-- Here we can specialise for f (\y -> ...)
-- because the rule-matcher will look through the let.
-argToPat in_scope con_env (Cast arg co) arg_occ
- = do { (interesting, arg') <- argToPat in_scope con_env arg arg_occ
- ; if interesting then
- return (interesting, Cast arg' co)
- else
- wildCardPat (snd (coercionKind co)) }
+argToPat in_scope val_env (Cast arg co) arg_occ
+ = do { (interesting, arg') <- argToPat in_scope val_env arg arg_occ
+ ; let (ty1,ty2) = coercionKind co
+ ; if not interesting then
+ wildCardPat ty2
+ else do
+ { -- Make a wild-card pattern for the coercion
+ uniq <- getUniqueUs
+ ; let co_name = mkSysTvName uniq FSLIT("sg")
+ co_var = mkCoVar co_name (mkCoKind ty1 ty2)
+ ; return (interesting, Cast arg' (mkTyVarTy co_var)) } }
{- Disabling lambda specialisation for now
It's fragile, and the spec_loop can be infinite
-argToPat in_scope con_env arg arg_occ
+argToPat in_scope val_env arg arg_occ
| is_value_lam arg
= return (True, arg)
where
-- Check for a constructor application
-- NB: this *precedes* the Var case, so that we catch nullary constrs
-argToPat in_scope con_env arg arg_occ
- | Just (CV dc args) <- isConApp con_env arg
+argToPat in_scope val_env arg arg_occ
+ | Just (ConVal dc args) <- isValue val_env arg
, case arg_occ of
ScrutOcc _ -> True -- Used only by case scrutinee
BothOcc -> case arg of -- Used elsewhere
App {} -> True -- see Note [Reboxing]
- other -> False
- other -> False -- No point; the arg is not decomposed
- = do { args' <- argsToPats in_scope con_env (args `zip` conArgOccs arg_occ dc)
+ _other -> False
+ _other -> False -- No point; the arg is not decomposed
+ = do { args' <- argsToPats in_scope val_env (args `zip` conArgOccs arg_occ dc)
; return (True, mk_con_app dc (map snd args')) }
-- Check if the argument is a variable that
-- It's worth specialising on this if
-- (a) it's used in an interesting way in the body
-- (b) we know what its value is
-argToPat in_scope con_env (Var v) arg_occ
- | not (isLocalId v) || v `elemInScopeSet` in_scope,
- case arg_occ of { UnkOcc -> False; other -> True }, -- (a)
- isValueUnfolding (idUnfolding v) -- (b)
+argToPat in_scope val_env (Var v) arg_occ
+ | case arg_occ of { UnkOcc -> False; _other -> True }, -- (a)
+ is_value -- (b)
= return (True, Var v)
+ where
+ is_value
+ | isLocalId v = v `elemInScopeSet` in_scope
+ && isJust (lookupVarEnv val_env v)
+ -- Local variables have values in val_env
+ | otherwise = isValueUnfolding (idUnfolding v)
+ -- Imports have unfoldings
-- I'm really not sure what this comment means
-- And by not wild-carding we tend to get forall'd
-- Don't make a wild-card, because we may usefully share
-- e.g. f a = let x = ... in f (x,x)
-- NB: this case follows the lambda and con-app cases!!
-argToPat in_scope con_env (Var v) arg_occ
+argToPat _in_scope _val_env (Var v) _arg_occ
= return (False, Var v)
-- The default case: make a wild-card
-argToPat in_scope con_env arg arg_occ
+argToPat _in_scope _val_env arg _arg_occ
= wildCardPat (exprType arg)
wildCardPat :: Type -> UniqSM (Bool, CoreArg)
; let id = mkSysLocal FSLIT("sc") uniq ty
; return (False, Var id) }
-argsToPats :: InScopeSet -> ConstrEnv
+argsToPats :: InScopeSet -> ValueEnv
-> [(CoreArg, ArgOcc)]
-> UniqSM [(Bool, CoreArg)]
-argsToPats in_scope con_env args
- = mapUs do_one args
+argsToPats in_scope val_env args
+ = mapM do_one args
where
- do_one (arg,occ) = argToPat in_scope con_env arg occ
+ do_one (arg,occ) = argToPat in_scope val_env arg occ
\end{code}
\begin{code}
-isConApp :: ConstrEnv -> CoreExpr -> Maybe ConValue
-isConApp env (Lit lit)
- = Just (CV (LitAlt lit) [])
-
-isConApp env expr -- Maybe it's a constructor application
- | (Var fun, args) <- collectArgs expr,
- Just con <- isDataConWorkId_maybe fun,
- args `lengthAtLeast` dataConRepArity con
- -- Might be > because the arity excludes type args
- = Just (CV (DataAlt con) args)
-
-isConApp env (Var v)
+isValue :: ValueEnv -> CoreExpr -> Maybe Value
+isValue _env (Lit lit)
+ = Just (ConVal (LitAlt lit) [])
+
+isValue env (Var v)
| Just stuff <- lookupVarEnv env v
= Just stuff -- You might think we could look in the idUnfolding here
-- but that doesn't take account of which branch of a
-- case we are in, which is the whole point
| not (isLocalId v) && isCheapUnfolding unf
- = isConApp env (unfoldingTemplate unf)
+ = isValue env (unfoldingTemplate unf)
where
unf = idUnfolding v
-- However we do want to consult the unfolding
-- as well, for let-bound constructors!
-isConApp env expr = Nothing
+isValue env (Lam b e)
+ | isTyVar b = isValue env e
+ | otherwise = Just LambdaVal
+
+isValue _env expr -- Maybe it's a constructor application
+ | (Var fun, args) <- collectArgs expr
+ = case isDataConWorkId_maybe fun of
+
+ Just con | args `lengthAtLeast` dataConRepArity con
+ -- Check saturated; might be > because the
+ -- arity excludes type args
+ -> Just (ConVal (DataAlt con) args)
+
+ _other | valArgCount args < idArity fun
+ -- Under-applied function
+ -> Just LambdaVal -- Partial application
+
+ _other -> Nothing
+
+isValue _env _expr = Nothing
mk_con_app :: AltCon -> [CoreArg] -> CoreExpr
mk_con_app (LitAlt lit) [] = Lit lit
mk_con_app (DataAlt con) args = mkConApp con args
-mk_con_app other args = panic "SpecConstr.mk_con_app"
+mk_con_app _other _args = panic "SpecConstr.mk_con_app"
samePat :: CallPat -> CallPat -> Bool
samePat (vs1, as1) (vs2, as2)
same (Lit l1) (Lit l2) = l1==l2
same (App f1 a1) (App f2 a2) = same f1 f2 && same a1 a2
- same (Type t1) (Type t2) = True -- Note [Ignore type differences]
+ same (Type {}) (Type {}) = True -- Note [Ignore type differences]
same (Note _ e1) e2 = same e1 e2 -- Ignore casts and notes
same (Cast e1 _) e2 = same e1 e2
same e1 (Note _ e2) = same e1 e2
same e1 e2 = WARN( bad e1 || bad e2, ppr e1 $$ ppr e2)
False -- Let, lambda, case should not occur
-#ifdef DEBUG
bad (Case {}) = True
bad (Let {}) = True
bad (Lam {}) = True
- bad other = False
-#endif
+ bad _other = False
\end{code}
Note [Ignore type differences]
projects / ghc-hetmet.git / blobdiff