X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FSimplUtils.lhs;h=cd610a9865325f65bb7a0ebcc5f303d4f9f8dd5c;hb=f37e239fb5e81fc493e0ea1af98178bf1f7ceaba;hp=202a6176d396ea902fa3c7ea2079f2950a76d77b;hpb=80965661715b664b4926fc525d0c89306b92e832;p=ghc-hetmet.git diff --git a/compiler/simplCore/SimplUtils.lhs b/compiler/simplCore/SimplUtils.lhs index 202a617..cd610a9 100644 --- a/compiler/simplCore/SimplUtils.lhs +++ b/compiler/simplCore/SimplUtils.lhs @@ -5,7 +5,7 @@ \begin{code} module SimplUtils ( - mkLam, mkCase, + mkLam, mkCase, -- Inlining, preInlineUnconditionally, postInlineUnconditionally, activeInline, activeRule, @@ -31,23 +31,29 @@ import StaticFlags ( opt_UF_UpdateInPlace, opt_SimplNoPreInlining, import CoreSyn import CoreFVs ( exprFreeVars ) import CoreUtils ( cheapEqExpr, exprType, exprIsTrivial, - etaExpand, exprEtaExpandArity, bindNonRec, mkCoerce2, - findDefault, exprOkForSpeculation, exprIsHNF, mergeAlts + etaExpand, exprEtaExpandArity, bindNonRec, mkCoerce, + findDefault, exprOkForSpeculation, exprIsHNF, mergeAlts, + applyTypeToArgs ) import Literal ( mkStringLit ) import CoreUnfold ( smallEnoughToInline ) -import MkId ( eRROR_ID ) +import MkId ( eRROR_ID, wrapNewTypeBody ) import Id ( Id, idType, isDataConWorkId, idOccInfo, isDictId, - isDeadBinder, idNewDemandInfo, isExportedId, + isDeadBinder, idNewDemandInfo, isExportedId, mkSysLocal, idUnfolding, idNewStrictness, idInlinePragma, idHasRules ) import NewDemand ( isStrictDmd, isBotRes, splitStrictSig ) import SimplMonad +import Var ( tyVarKind, mkTyVar ) +import Name ( mkSysTvName ) import Type ( Type, splitFunTys, dropForAlls, isStrictType, - splitTyConApp_maybe, tyConAppArgs + splitTyConApp_maybe, tyConAppArgs, mkTyVarTys ) +import Coercion ( isEqPredTy ) -import TyCon ( tyConDataCons_maybe ) -import DataCon ( dataConRepArity ) +import Coercion ( Coercion, mkUnsafeCoercion, coercionKind ) +import TyCon ( tyConDataCons_maybe, isClosedNewTyCon ) +import DataCon ( DataCon, dataConRepArity, dataConExTyVars, + dataConInstArgTys, dataConTyCon ) import VarSet import BasicTypes ( TopLevelFlag(..), isNotTopLevel, OccInfo(..), isLoopBreaker, isOneOcc, Activation, isAlwaysActive, isActive ) @@ -75,12 +81,14 @@ data SimplCont -- Strict contexts -- (b) This is an argument of a function that has RULES -- Inlining the call might allow the rule to fire - | CoerceIt OutType -- The To-type, simplified + | CoerceIt OutCoercion -- The coercion simplified SimplCont | ApplyTo DupFlag - InExpr SimplEnv -- The argument, as yet unsimplified, - SimplCont -- and its environment + CoreExpr -- The argument + (Maybe SimplEnv) -- (Just se) => the arg is un-simplified and this is its subst-env + -- Nothing => the arg is already simplified; don't repeatedly simplify it! + SimplCont -- and its environment | Select DupFlag InId [InAlt] SimplEnv -- The case binder, alts, and subst-env @@ -112,7 +120,7 @@ instance Outputable SimplCont where ppr (ArgOf _ _ _ _) = ptext SLIT("ArgOf...") ppr (Select dup bndr alts se cont) = (ptext SLIT("Select") <+> ppr dup <+> ppr bndr) $$ (nest 4 (ppr alts)) $$ ppr cont - ppr (CoerceIt ty cont) = (ptext SLIT("CoerceIt") <+> ppr ty) $$ ppr cont + ppr (CoerceIt co cont) = (ptext SLIT("CoerceIt") <+> ppr co) $$ ppr cont data DupFlag = OkToDup | NoDup @@ -121,6 +129,7 @@ instance Outputable DupFlag where ppr NoDup = ptext SLIT("nodup") + ------------------- mkBoringStop :: OutType -> SimplCont mkBoringStop ty = Stop ty AnArg False @@ -154,13 +163,15 @@ discardableCont (Stop _ _ _) = False discardableCont (CoerceIt _ cont) = discardableCont cont discardableCont other = True -discardCont :: SimplCont -- A continuation, expecting +discardCont :: Type -- The type expected + -> SimplCont -- A continuation, expecting the previous type -> SimplCont -- Replace the continuation with a suitable coerce -discardCont cont = case cont of +discardCont from_ty cont = case cont of Stop to_ty is_rhs _ -> cont - other -> CoerceIt to_ty (mkBoringStop to_ty) + other -> CoerceIt co (mkBoringStop to_ty) where - to_ty = contResultType cont + co = mkUnsafeCoercion from_ty to_ty + to_ty = contResultType cont ------------------- contResultType :: SimplCont -> OutType @@ -181,18 +192,18 @@ countArgs (ApplyTo _ arg se cont) = 1 + countArgs cont countArgs other = 0 ------------------- -pushContArgs :: SimplEnv -> [OutArg] -> SimplCont -> SimplCont +pushContArgs ::[OutArg] -> SimplCont -> SimplCont -- Pushes args with the specified environment -pushContArgs env [] cont = cont -pushContArgs env (arg : args) cont = ApplyTo NoDup arg env (pushContArgs env args cont) +pushContArgs [] cont = cont +pushContArgs (arg : args) cont = ApplyTo NoDup arg Nothing (pushContArgs args cont) \end{code} \begin{code} getContArgs :: SwitchChecker -> OutId -> SimplCont - -> ([(InExpr, SimplEnv, Bool)], -- Arguments; the Bool is true for strict args - SimplCont) -- Remaining continuation + -> ([(InExpr, Maybe SimplEnv, Bool)], -- Arguments; the Bool is true for strict args + SimplCont) -- Remaining continuation -- getContArgs id k = (args, k', inl) -- args are the leading ApplyTo items in k -- (i.e. outermost comes first) @@ -228,17 +239,24 @@ getContArgs chkr fun orig_cont -- Then, especially in the first of these cases, we'd like to discard -- the continuation, leaving just the bottoming expression. But the -- type might not be right, so we may have to add a coerce. - go acc ss cont - | null ss && discardableCont cont = (reverse acc, discardCont cont) - | otherwise = (reverse acc, cont) + go acc ss cont + | null ss && discardableCont cont = (args, discardCont hole_ty cont) + | otherwise = (args, cont) + where + args = reverse acc + hole_ty = applyTypeToArgs (Var fun) (idType fun) + [substExpr_mb se arg | (arg,se,_) <- args] + substExpr_mb Nothing arg = arg + substExpr_mb (Just se) arg = substExpr se arg + ---------------------------- vanilla_stricts, computed_stricts :: [Bool] vanilla_stricts = repeat False computed_stricts = zipWith (||) fun_stricts arg_stricts ---------------------------- - (val_arg_tys, _) = splitFunTys (dropForAlls (idType fun)) + (val_arg_tys, res_ty) = splitFunTys (dropForAlls (idType fun)) arg_stricts = map isStrictType val_arg_tys ++ repeat False -- These argument types are used as a cheap and cheerful way to find -- unboxed arguments, which must be strict. But it's an InType @@ -374,12 +392,12 @@ interestingCallContext :: Bool -- False <=> no args at all interestingCallContext some_args some_val_args cont = interesting cont where - interesting (Select _ _ _ _ _) = some_args - interesting (ApplyTo _ _ _ _) = True -- Can happen if we have (coerce t (f x)) y + interesting (Select {}) = some_args + interesting (ApplyTo {}) = True -- Can happen if we have (coerce t (f x)) y -- Perhaps True is a bit over-keen, but I've -- seen (coerce f) x, where f has an INLINE prag, -- So we have to give some motivaiton for inlining it - interesting (ArgOf _ _ _ _) = some_val_args + interesting (ArgOf {}) = some_val_args interesting (Stop ty _ interesting) = some_val_args && interesting interesting (CoerceIt _ cont) = interesting cont -- If this call is the arg of a strict function, the context @@ -746,6 +764,11 @@ postInlineUnconditionally env top_lvl bndr occ_info rhs unfolding -- int_cxt to prevent us inlining inside a lambda without some -- good reason. See the notes on int_cxt in preInlineUnconditionally + IAmDead -> True -- This happens; for example, the case_bndr during case of + -- known constructor: case (a,b) of x { (p,q) -> ... } + -- Here x isn't mentioned in the RHS, so we don't want to + -- create the (dead) let-binding let x = (a,b) in ... + other -> False -- Here's an example that we don't handle well: @@ -1116,6 +1139,7 @@ tryRhsTyLam env tyvars body -- Only does something if there's a let %* * %************************************************************************ + mkCase puts a case expression back together, trying various transformations first. \begin{code} @@ -1438,28 +1462,32 @@ mkCase1 scrut case_bndr ty [(con,bndrs,rhs)] mkCase1 scrut case_bndr ty alts -- Identity case | all identity_alt alts = tick (CaseIdentity case_bndr) `thenSmpl_` - returnSmpl (re_note scrut) + returnSmpl (re_cast scrut) where - identity_alt (con, args, rhs) = de_note rhs `cheapEqExpr` identity_rhs con args + identity_alt (con, args, rhs) = de_cast rhs `cheapEqExpr` mk_id_rhs con args - identity_rhs (DataAlt con) args = mkConApp con (arg_tys ++ map varToCoreExpr args) - identity_rhs (LitAlt lit) _ = Lit lit - identity_rhs DEFAULT _ = Var case_bndr + mk_id_rhs (DataAlt con) args = mkConApp con (arg_tys ++ varsToCoreExprs args) + mk_id_rhs (LitAlt lit) _ = Lit lit + mk_id_rhs DEFAULT _ = Var case_bndr arg_tys = map Type (tyConAppArgs (idType case_bndr)) -- We've seen this: - -- case coerce T e of x { _ -> coerce T' x } - -- And we definitely want to eliminate this case! - -- So we throw away notes from the RHS, and reconstruct - -- (at least an approximation) at the other end - de_note (Note _ e) = de_note e - de_note e = e - - -- re_note wraps a coerce if it might be necessary - re_note scrut = case head alts of - (_,_,rhs1@(Note _ _)) -> mkCoerce2 (exprType rhs1) (idType case_bndr) scrut - other -> scrut + -- case e of x { _ -> x `cast` c } + -- And we definitely want to eliminate this case, to give + -- e `cast` c + -- So we throw away the cast from the RHS, and reconstruct + -- it at the other end. All the RHS casts must be the same + -- if (all identity_alt alts) holds. + -- + -- Don't worry about nested casts, because the simplifier combines them + de_cast (Cast e _) = e + de_cast e = e + + re_cast scrut = case head alts of + (_,_,Cast _ co) -> Cast scrut co + other -> scrut + --------------------------------------------------