X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FsimplCore%2FSimplUtils.lhs;h=3f5c1a5f2fa91213e30d67954b072c3298213dd1;hb=0596517a9b4b2b32e5d375a986351102ac4540fc;hp=d1bd744fce0ff1ad743c11324236a9c129806d16;hpb=6c381e873e222417d9a67aeec77b9555eca7b7a8;p=ghc-hetmet.git diff --git a/ghc/compiler/simplCore/SimplUtils.lhs b/ghc/compiler/simplCore/SimplUtils.lhs index d1bd744..3f5c1a5 100644 --- a/ghc/compiler/simplCore/SimplUtils.lhs +++ b/ghc/compiler/simplCore/SimplUtils.lhs @@ -10,7 +10,7 @@ module SimplUtils ( floatExposesHNF, - mkCoTyLamTryingEta, mkCoLamTryingEta, + mkTyLamTryingEta, mkValLamTryingEta, etaExpandCount, @@ -21,33 +21,21 @@ module SimplUtils ( type_ok_for_let_to_case ) where -IMPORT_Trace -- ToDo: rm (debugging) -import Pretty +import Ubiq{-uitous-} +import BinderInfo +import CoreSyn +import CoreUtils ( manifestlyWHNF ) +import Id ( idType, isBottomingId, getIdArity ) +import IdInfo ( arityMaybe ) +import Maybes ( maybeToBool ) +import PrelInfo ( augmentId, buildId, realWorldStateTy ) import SimplEnv import SimplMonad +import Type ( isPrimType, maybeAppDataTyCon, getTyVar_maybe ) +import Util ( isIn, panic ) -import BinderInfo - -import PrelInfo ( primOpIsCheap, realWorldStateTy, - buildId, augmentId - IF_ATTACK_PRAGMAS(COMMA realWorldTy) - IF_ATTACK_PRAGMAS(COMMA tagOf_PrimOp) - IF_ATTACK_PRAGMAS(COMMA pprPrimOp) - ) -import Type ( extractTyVarsFromTy, getTyVarMaybe, isPrimType, - splitTypeWithDictsAsArgs, maybeDataTyCon, - applyTy, isFunType, TyVar, TyVarTemplate - ) -import Id ( getInstantiatedDataConSig, isDataCon, idType, - getIdArity, isBottomingId, idWantsToBeINLINEd, - DataCon(..), Id - ) -import IdInfo -import CmdLineOpts ( SimplifierSwitch(..) ) -import Maybes ( maybeToBool, Maybe(..) ) -import Outputable -- isExported ... -import Util +primOpIsCheap = panic "SimplUtils. (ToDo)" \end{code} @@ -79,8 +67,8 @@ floatExposesHNF float_lets float_primops ok_to_dup rhs -- because it *will* become one. -- likewise for `augment g h' -- - try (App (CoTyApp (Var bld) _) _) | bld == buildId = True - try (App (App (CoTyApp (Var bld) _) _) _) | bld == augmentId = True + try (App (App (Var bld) _) _) | bld == buildId = True + try (App (App (App (Var aug) _) _) _) | aug == augmentId = True try other = manifestlyWHNF other {- but *not* necessarily "manifestlyBottom other"... @@ -99,7 +87,7 @@ floatExposesHNF float_lets float_primops ok_to_dup rhs to allocate it eagerly as that's a waste. -} - try_alt (lit,rhs) = try rhs + try_alt (lit,rhs) = try rhs try_deflt NoDefault = False try_deflt (BindDefault _ rhs) = try rhs @@ -127,13 +115,13 @@ gives rise to a recursive function for the list comprehension, and f turns out to be just a single call to this recursive function. \begin{code} -mkCoLamTryingEta :: [Id] -- Args to the lambda +mkValLamTryingEta :: [Id] -- Args to the lambda -> CoreExpr -- Lambda body -> CoreExpr -mkCoLamTryingEta [] body = body +mkValLamTryingEta [] body = body -mkCoLamTryingEta orig_ids body +mkValLamTryingEta orig_ids body = reduce_it (reverse orig_ids) body where bale_out = mkValLam orig_ids body @@ -150,16 +138,18 @@ mkCoLamTryingEta orig_ids body reduce_it ids other = bale_out - is_elem = isIn "mkCoLamTryingEta" + is_elem = isIn "mkValLamTryingEta" ----------- residual_ok :: CoreExpr -> Bool -- Checks for type application - -- and function not one of the - -- bound vars - residual_ok (CoTyApp fun ty) = residual_ok fun - residual_ok (Var v) = not (v `is_elem` orig_ids) -- Fun mustn't be one of - -- the bound ids - residual_ok other = False + -- and function not one of the + -- bound vars + + residual_ok (Var v) = not (v `is_elem` orig_ids) + -- Fun mustn't be one of the bound ids + residual_ok (App fun arg) + | notValArg arg = residual_ok fun + residual_ok other = False \end{code} Eta expansion @@ -169,20 +159,22 @@ such that E ===> (\x1::t1 x1::t2 ... xn::tn -> E x1 x2 ... xn) -is a safe transformation. In particular, the transformation should not -cause work to be duplicated, unless it is ``cheap'' (see @manifestlyCheap@ below). +is a safe transformation. In particular, the transformation should +not cause work to be duplicated, unless it is ``cheap'' (see +@manifestlyCheap@ below). -@etaExpandCount@ errs on the conservative side. It is always safe to return 0. +@etaExpandCount@ errs on the conservative side. It is always safe to +return 0. An application of @error@ is special, because it can absorb as many -arguments as you care to give it. For this special case we return 100, -to represent "infinity", which is a bit of a hack. +arguments as you care to give it. For this special case we return +100, to represent "infinity", which is a bit of a hack. \begin{code} etaExpandCount :: GenCoreExpr bdr Id - -> Int -- Number of extra args you can safely abstract + -> Int -- Number of extra args you can safely abstract -etaExpandCount (Lam _ body) +etaExpandCount (Lam (ValBinder _) body) = 1 + etaExpandCount body etaExpandCount (Let bind body) @@ -193,37 +185,38 @@ etaExpandCount (Case scrut alts) | manifestlyCheap scrut = minimum [etaExpandCount rhs | rhs <- rhssOfAlts alts] -etaExpandCount (App fun _) = case etaExpandCount fun of - 0 -> 0 - n -> n-1 -- Knock off one - -etaExpandCount fun@(CoTyApp _ _) = eta_fun fun etaExpandCount fun@(Var _) = eta_fun fun +etaExpandCount (App fun arg) + | notValArg arg = eta_fun fun + | otherwise = case etaExpandCount fun of + 0 -> 0 + n -> n-1 -- Knock off one -etaExpandCount other = 0 -- Give up +etaExpandCount other = 0 -- Give up -- Lit, Con, Prim, - -- CoTyLam, + -- non-val Lam, -- Scc (pessimistic; ToDo), -- Let with non-whnf rhs(s), -- Case with non-whnf scrutinee +----------------------------- eta_fun :: GenCoreExpr bdr Id -- The function -> Int -- How many args it can safely be applied to -eta_fun (CoTyApp fun ty) = eta_fun fun +eta_fun (App fun arg) | notValArg arg = eta_fun fun eta_fun expr@(Var v) - | isBottomingId v -- Bottoming ids have "infinite arity" - = 10000 -- Blargh. Infinite enough! + | isBottomingId v -- Bottoming ids have "infinite arity" + = 10000 -- Blargh. Infinite enough! eta_fun expr@(Var v) - | maybeToBool arity_maybe -- We know the arity + | maybeToBool arity_maybe -- We know the arity = arity where arity_maybe = arityMaybe (getIdArity v) arity = case arity_maybe of { Just arity -> arity } -eta_fun other = 0 -- Give up +eta_fun other = 0 -- Give up \end{code} @manifestlyCheap@ looks at a Core expression and returns \tr{True} if @@ -252,10 +245,11 @@ manifestlyCheap :: GenCoreExpr bndr Id -> Bool manifestlyCheap (Var _) = True manifestlyCheap (Lit _) = True manifestlyCheap (Con _ _ _) = True -manifestlyCheap (Lam _ _) = True -manifestlyCheap (CoTyLam _ e) = manifestlyCheap e manifestlyCheap (SCC _ e) = manifestlyCheap e +manifestlyCheap (Lam (ValBinder _) _) = True +manifestlyCheap (Lam other_binder e) = manifestlyCheap e + manifestlyCheap (Prim op _ _) = primOpIsCheap op manifestlyCheap (Let bind body) @@ -268,20 +262,20 @@ manifestlyCheap other_expr -- look for manifest partial application = case (collectArgs other_expr) of { (fun, args) -> case fun of - Var f | isBottomingId f -> True -- Application of a function which - -- always gives bottom; we treat this as - -- a WHNF, because it certainly doesn't - -- need to be shared! + Var f | isBottomingId f -> True -- Application of a function which + -- always gives bottom; we treat this as + -- a WHNF, because it certainly doesn't + -- need to be shared! Var f -> let - num_val_args = length [ a | (ValArg a) <- args ] - in - num_val_args == 0 || -- Just a type application of - -- a variable (f t1 t2 t3) - -- counts as WHNF - case (arityMaybe (getIdArity f)) of - Nothing -> False - Just arity -> num_val_args < arity + num_val_args = numValArgs args + in + num_val_args == 0 || -- Just a type application of + -- a variable (f t1 t2 t3) + -- counts as WHNF + case (arityMaybe (getIdArity f)) of + Nothing -> False + Just arity -> num_val_args < arity _ -> False } @@ -321,9 +315,9 @@ applications since this breaks the specialiser: /\ a -> f Char# a =NO=> f Char# \begin{code} -mkCoTyLamTryingEta :: [TyVar] -> CoreExpr -> CoreExpr +mkTyLamTryingEta :: [TyVar] -> CoreExpr -> CoreExpr -mkCoTyLamTryingEta tyvars tylam_body +mkTyLamTryingEta tyvars tylam_body = if tyvars == tyvar_args && -- Same args in same order check_fun fun -- Function left is ok @@ -332,15 +326,18 @@ mkCoTyLamTryingEta tyvars tylam_body fun else -- The vastly common case - mkCoTyLam tyvars tylam_body + mkTyLam tyvars tylam_body where (tyvar_args, fun) = strip_tyvar_args [] tylam_body - strip_tyvar_args args_so_far tyapp@(CoTyApp fun ty) - = case getTyVarMaybe ty of + strip_tyvar_args args_so_far tyapp@(App fun (TyArg ty)) + = case getTyVar_maybe ty of Just tyvar_arg -> strip_tyvar_args (tyvar_arg:args_so_far) fun Nothing -> (args_so_far, tyapp) + strip_tyvar_args args_so_far (App _ (UsageArg _)) + = panic "SimplUtils.mkTyLamTryingEta: strip_tyvar_args UsageArg" + strip_tyvar_args args_so_far fun = (args_so_far, fun) @@ -373,7 +370,7 @@ mkIdentityAlts rhs_ty returnSmpl (PrimAlts [] (BindDefault (binder, bad_occ_info) (Var binder))) | otherwise - = case maybeDataTyCon rhs_ty of + = case (maybeAppDataTyCon rhs_ty) of Just (tycon, ty_args, [data_con]) -> -- algebraic type suitable for unpacking let (_,inst_con_arg_tys,_) = getInstantiatedDataConSig data_con ty_args @@ -406,7 +403,7 @@ simplIdWantsToBeINLINEd id env type_ok_for_let_to_case :: Type -> Bool type_ok_for_let_to_case ty - = case maybeDataTyCon ty of + = case (maybeAppDataTyCon ty) of Nothing -> False Just (tycon, ty_args, []) -> False Just (tycon, ty_args, non_null_data_cons) -> True