X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FSimplEnv.lhs;h=1d7d2e4420eea9a6e69420eb689aaf42b59e85c4;hb=418175d3c36ca51495d9dfb085fb01711e4c38f9;hp=c9fb4fbb8ba23d5d9471a535c0498c71fe0609e1;hpb=6f074a37a1546391632863898da3c32bbb7995df;p=ghc-hetmet.git diff --git a/compiler/simplCore/SimplEnv.lhs b/compiler/simplCore/SimplEnv.lhs index c9fb4fb..1d7d2e4 100644 --- a/compiler/simplCore/SimplEnv.lhs +++ b/compiler/simplCore/SimplEnv.lhs @@ -9,8 +9,6 @@ module SimplEnv ( OutId, OutTyVar, OutBind, OutExpr, OutAlt, OutArg, OutType, OutBndr, InCoercion, OutCoercion, - isStrictBndr, - -- The simplifier mode setMode, getMode, @@ -34,9 +32,9 @@ module SimplEnv ( substExpr, substTy, -- Floats - Floats, emptyFloats, isEmptyFloats, addNonRec, addFloats, - wrapFloats, floatBinds, setFloats, canFloat, zapFloats, addRecFloats, - getFloats + Floats, emptyFloats, isEmptyFloats, addNonRec, addFloats, extendFloats, + wrapFloats, floatBinds, setFloats, zapFloats, addRecFloats, + doFloatFromRhs, getFloats ) where #include "HsVersions.h" @@ -46,14 +44,12 @@ import IdInfo import CoreSyn import Rules import CoreUtils -import CoreFVs import CostCentre import Var import VarEnv import VarSet import OrdList import Id -import NewDemand import qualified CoreSubst ( Subst, mkSubst, substExpr, substSpec, substWorker ) import qualified Type ( substTy, substTyVarBndr ) import Type hiding ( substTy, substTyVarBndr ) @@ -61,7 +57,6 @@ import Coercion import BasicTypes import DynFlags import Util -import UniqFM import Outputable \end{code} @@ -92,13 +87,6 @@ type OutAlt = CoreAlt type OutArg = CoreArg \end{code} -\begin{code} -isStrictBndr :: Id -> Bool -isStrictBndr bndr - = ASSERT2( isId bndr, ppr bndr ) - isStrictDmd (idNewDemandInfo bndr) || isStrictType (idType bndr) -\end{code} - %************************************************************************ %* * \subsubsection{The @SimplEnv@ type} @@ -113,9 +101,6 @@ data SimplEnv seChkr :: SwitchChecker, seCC :: CostCentreStack, -- The enclosing CCS (when profiling) - -- Rules from other modules - seExtRules :: RuleBase, - -- The current set of in-scope variables -- They are all OutVars, and all bound in this module seInScope :: InScopeSet, -- OutVars only @@ -219,11 +204,11 @@ seIdSubst: \begin{code} -mkSimplEnv :: SimplifierMode -> SwitchChecker -> RuleBase -> SimplEnv -mkSimplEnv mode switches rules +mkSimplEnv :: SimplifierMode -> SwitchChecker -> SimplEnv +mkSimplEnv mode switches = SimplEnv { seChkr = switches, seCC = subsumedCCS, seMode = mode, seInScope = emptyInScopeSet, - seExtRules = rules, seFloats = emptyFloats, + seFloats = emptyFloats, seTvSubst = emptyVarEnv, seIdSubst = emptyVarEnv } -- The top level "enclosing CC" is "SUBSUMED". @@ -301,10 +286,6 @@ mkContEx (SimplEnv { seTvSubst = tvs, seIdSubst = ids }) e = ContEx tvs ids e isEmptySimplSubst :: SimplEnv -> Bool isEmptySimplSubst (SimplEnv { seTvSubst = tvs, seIdSubst = ids }) = isEmptyVarEnv tvs && isEmptyVarEnv ids - ---------------------- -getRules :: SimplEnv -> RuleBase -getRules = seExtRules \end{code} @@ -321,11 +302,13 @@ The Floats is a bunch of bindings, classified by a FloatFlag. NonRec x (y:ys) FltLifted Rec [(x,rhs)] FltLifted - NonRec x# (y +# 3) FltOkSpec + + NonRec x# (y +# 3) FltOkSpec -- Unboxed, but ok-for-spec'n + NonRec x# (a /# b) FltCareful - NonRec x* (f y) FltCareful -- Might fail or diverge - NonRec x# (f y) FltCareful -- Might fail or diverge - (where f :: Int -> Int#) + NonRec x* (f y) FltCareful -- Strict binding; might fail or diverge + NonRec x# (f y) FltCareful -- Unboxed binding: might fail or diverge + -- (where f :: Int -> Int#) \begin{code} data Floats = Floats (OrdList OutBind) FloatFlag @@ -364,18 +347,19 @@ andFF FltLifted flt = flt classifyFF :: CoreBind -> FloatFlag classifyFF (Rec _) = FltLifted classifyFF (NonRec bndr rhs) - | not (isStrictBndr bndr) = FltLifted + | not (isStrictId bndr) = FltLifted | exprOkForSpeculation rhs = FltOkSpec | otherwise = FltCareful -canFloat :: TopLevelFlag -> RecFlag -> Bool -> SimplEnv -> Bool -canFloat lvl rec str (SimplEnv {seFloats = Floats _ ff}) - = canFloatFlt lvl rec str ff - -canFloatFlt :: TopLevelFlag -> RecFlag -> Bool -> FloatFlag -> Bool -canFloatFlt lvl rec str FltLifted = True -canFloatFlt lvl rec str FltOkSpec = isNotTopLevel lvl && isNonRec rec -canFloatFlt lvl rec str FltCareful = str && isNotTopLevel lvl && isNonRec rec +doFloatFromRhs :: TopLevelFlag -> RecFlag -> Bool -> OutExpr -> SimplEnv -> Bool +doFloatFromRhs lvl rec str rhs (SimplEnv {seFloats = Floats fs ff}) + = not (isNilOL fs) && want_to_float && can_float + where + want_to_float = isTopLevel lvl || exprIsCheap rhs + can_float = case ff of + FltLifted -> True + FltOkSpec -> isNotTopLevel lvl && isNonRec rec + FltCareful -> isNotTopLevel lvl && isNonRec rec && str \end{code} @@ -396,6 +380,16 @@ addNonRec env id rhs = env { seFloats = seFloats env `addFlts` unitFloat (NonRec id rhs), seInScope = extendInScopeSet (seInScope env) id } +extendFloats :: SimplEnv -> [OutBind] -> SimplEnv +-- Add these bindings to the floats, and extend the in-scope env too +extendFloats env binds + = env { seFloats = seFloats env `addFlts` new_floats, + seInScope = extendInScopeSetList (seInScope env) bndrs } + where + bndrs = bindersOfBinds binds + new_floats = Floats (toOL binds) + (foldr (andFF . classifyFF) FltLifted binds) + addFloats :: SimplEnv -> SimplEnv -> SimplEnv -- Add the floats for env2 to env1; -- *plus* the in-scope set for env2, which is bigger @@ -608,8 +602,12 @@ substLetIdBndr :: SimplEnv -> InBndr -- Env and binder to transform -> (SimplEnv, OutBndr) -- C.f. substIdBndr above -- Clone Id if necessary, substitute its type --- Return an Id with completely zapped IdInfo +-- Return an Id with its fragile info zapped +-- namely, any info that depends on free variables -- [addLetIdInfo, below, will restore its IdInfo] +-- We want to retain robust info, especially arity and demand info, +-- so that they are available to occurrences that occur in an +-- earlier binding of a letrec -- Augment the subtitution -- if the unique changed, *or* -- if there's interesting occurrence info @@ -620,7 +618,10 @@ substLetIdBndr env@(SimplEnv { seInScope = in_scope, seIdSubst = id_subst }) old where id1 = uniqAway in_scope old_id id2 = substIdType env id1 - new_id = setIdInfo id2 vanillaIdInfo + + -- We want to get rid of any info that's dependent on free variables, + -- but keep other info (like the arity). + new_id = zapFragileIdInfo id2 -- Extend the substitution if the unique has changed, -- or there's some useful occurrence information @@ -631,8 +632,8 @@ substLetIdBndr env@(SimplEnv { seInScope = in_scope, seIdSubst = id_subst }) old = delVarEnv id_subst old_id \end{code} -Add IdInfo back onto a let-bound Id -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Note [Add IdInfo back onto a let-bound Id] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We must transfer the IdInfo of the original binder to the new binder. This is crucial, to preserve strictness