X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FsimplCore%2FSimplify.lhs;h=dffdd75212206ead238a652ac81f1e75551ddc9c;hp=b30ed048e48f72607d4c88d4cd760c043423d874;hb=9da4639011348fb6c318e3cba4b08622f811d9c4;hpb=c55001c567b4f6e17f7a0c174c003318aac6a8ed diff --git a/compiler/simplCore/Simplify.lhs b/compiler/simplCore/Simplify.lhs index b30ed04..dffdd75 100644 --- a/compiler/simplCore/Simplify.lhs +++ b/compiler/simplCore/Simplify.lhs @@ -13,7 +13,7 @@ import DynFlags ( dopt, DynFlag(Opt_D_dump_inlinings), ) import SimplMonad import SimplEnv -import SimplUtils ( mkCase, mkLam, +import SimplUtils ( mkCase, mkLam, SimplCont(..), DupFlag(..), LetRhsFlag(..), mkRhsStop, mkBoringStop, mkLazyArgStop, pushContArgs, contResultType, countArgs, contIsDupable, contIsRhsOrArg, @@ -26,17 +26,14 @@ import Id ( Id, idType, idInfo, idArity, isDataConWorkId, idNewDemandInfo, setIdInfo, setIdOccInfo, zapLamIdInfo, setOneShotLambda ) -import MkId ( eRROR_ID ) -import Literal ( mkStringLit ) import IdInfo ( OccInfo(..), isLoopBreaker, setArityInfo, zapDemandInfo, setUnfoldingInfo, occInfo ) import NewDemand ( isStrictDmd ) -import Unify ( coreRefineTys, dataConCanMatch ) -import DataCon ( DataCon, dataConTyCon, dataConRepStrictness, isVanillaDataCon, - dataConInstArgTys, dataConTyVars ) +import TcGadt ( dataConCanMatch ) +import DataCon ( dataConTyCon, dataConRepStrictness ) import TyCon ( tyConArity, isAlgTyCon, isNewTyCon, tyConDataCons_maybe ) import CoreSyn import PprCore ( pprParendExpr, pprCoreExpr ) @@ -45,24 +42,24 @@ import CoreUtils ( exprIsDupable, exprIsTrivial, needsCaseBinding, exprIsConApp_maybe, mkPiTypes, findAlt, exprType, exprIsHNF, findDefault, mergeAlts, exprOkForSpeculation, exprArity, - mkCoerce, mkCoerce2, mkSCC, mkInlineMe, applyTypeToArg + mkCoerce, mkSCC, mkInlineMe, applyTypeToArg, + dataConRepInstPat ) import Rules ( lookupRule ) import BasicTypes ( isMarkedStrict ) import CostCentre ( currentCCS ) import Type ( TvSubstEnv, isUnLiftedType, seqType, tyConAppArgs, funArgTy, - splitFunTy_maybe, splitFunTy, coreEqType, splitTyConApp_maybe, - isTyVarTy, mkTyVarTys + coreEqType, splitTyConApp_maybe, + isTyVarTy, isFunTy, tcEqType ) -import Var ( tyVarKind, mkTyVar ) +import Coercion ( Coercion, coercionKind, + mkTransCoercion, mkSymCoercion, splitCoercionKind_maybe, decomposeCo ) import VarEnv ( elemVarEnv, emptyVarEnv ) import TysPrim ( realWorldStatePrimTy ) import PrelInfo ( realWorldPrimId ) import BasicTypes ( TopLevelFlag(..), isTopLevel, RecFlag(..), isNonRec ) -import Name ( mkSysTvName ) -import StaticFlags ( opt_PprStyle_Debug ) import OrdList import List ( nub ) import Maybes ( orElse ) @@ -537,8 +534,8 @@ simplLazyBind env top_lvl is_rec bndr bndr1 rhs rhs_se -- we only float if (a) arg' is a WHNF, or (b) it's going to top level -- and so there can't be any 'will be demanded' bindings in the floats. -- Hence the warning - ASSERT2( is_top_level || not (any demanded_float (floatBinds floats)), - ppr (filter demanded_float (floatBinds floats)) ) + WARN( not (is_top_level || not (any demanded_float (floatBinds floats))), + ppr (filter demanded_float (floatBinds floats)) ) tick LetFloatFromLet `thenSmpl_` ( addFloats env1 floats $ \ env2 -> @@ -611,7 +608,6 @@ completeLazyBind env top_lvl old_bndr new_bndr new_rhs -- means that we can avoid tests in exprIsConApp, for example. -- This is important: if exprIsConApp says 'yes' for a recursive -- thing, then we can get into an infinite loop - -- If the unfolding is a value, the demand info may -- go pear-shaped, so we nuke it. Example: -- let x = (a,b) in @@ -715,7 +711,9 @@ simplExprF env (Var v) cont = simplVar env v cont simplExprF env (Lit lit) cont = rebuild env (Lit lit) cont simplExprF env expr@(Lam _ _) cont = simplLam env expr cont simplExprF env (Note note expr) cont = simplNote env note expr cont -simplExprF env (App fun arg) cont = simplExprF env fun (ApplyTo NoDup arg (Just env) cont) +simplExprF env (Cast body co) cont = simplCast env body co cont +simplExprF env (App fun arg) cont = simplExprF env fun + (ApplyTo NoDup arg (Just env) cont) simplExprF env (Type ty) cont = ASSERT( contIsRhsOrArg cont ) @@ -768,6 +766,69 @@ simplType env ty %************************************************************************ \begin{code} +simplCast :: SimplEnv -> InExpr -> Coercion -> SimplCont -> SimplM FloatsWithExpr +simplCast env body co cont + = let + addCoerce co cont + | (s1, k1) <- coercionKind co + , s1 `tcEqType` k1 = cont + addCoerce co1 (CoerceIt co2 cont) + | (s1, k1) <- coercionKind co1 + , (l1, t1) <- coercionKind co2 + -- coerce T1 S1 (coerce S1 K1 e) + -- ==> + -- e, if T1=K1 + -- coerce T1 K1 e, otherwise + -- + -- For example, in the initial form of a worker + -- we may find (coerce T (coerce S (\x.e))) y + -- and we'd like it to simplify to e[y/x] in one round + -- of simplification + , s1 `coreEqType` t1 = cont -- The coerces cancel out + | otherwise = CoerceIt (mkTransCoercion co1 co2) cont + + addCoerce co (ApplyTo dup arg arg_se cont) + | not (isTypeArg arg) -- This whole case only works for value args + -- Could upgrade to have equiv thing for type apps too + , Just (s1s2, t1t2) <- splitCoercionKind_maybe co + , isFunTy s1s2 + -- co : s1s2 :=: t1t2 + -- (coerce (T1->T2) (S1->S2) F) E + -- ===> + -- coerce T2 S2 (F (coerce S1 T1 E)) + -- + -- t1t2 must be a function type, T1->T2, because it's applied + -- to something but s1s2 might conceivably not be + -- + -- When we build the ApplyTo we can't mix the out-types + -- with the InExpr in the argument, so we simply substitute + -- to make it all consistent. It's a bit messy. + -- But it isn't a common case. + = result + where + -- we split coercion t1->t2 :=: s1->s2 into t1 :=: s1 and + -- t2 :=: s2 with left and right on the curried form: + -- (->) t1 t2 :=: (->) s1 s2 + [co1, co2] = decomposeCo 2 co + new_arg = mkCoerce (mkSymCoercion co1) arg' + arg' = case arg_se of + Nothing -> arg + Just arg_se -> substExpr (setInScope arg_se env) arg + result = ApplyTo dup new_arg (Just $ zapSubstEnv env) + (addCoerce co2 cont) + addCoerce co cont = CoerceIt co cont + in + simplType env co `thenSmpl` \ co' -> + simplExprF env body (addCoerce co' cont) +\end{code} + +%************************************************************************ +%* * +\subsection{Lambdas} +%* * +%************************************************************************ + +\begin{code} simplLam env fun cont = go env fun cont where @@ -829,56 +890,6 @@ mkLamBndrZapper fun n_args %************************************************************************ \begin{code} -simplNote env (Coerce to from) body cont - = let - addCoerce s1 k1 cont -- Drop redundant coerces. This can happen if a polymoprhic - -- (coerce a b e) is instantiated with a=ty1 b=ty2 and the - -- two are the same. This happens a lot in Happy-generated parsers - | s1 `coreEqType` k1 = cont - - addCoerce s1 k1 (CoerceIt t1 cont) - -- coerce T1 S1 (coerce S1 K1 e) - -- ==> - -- e, if T1=K1 - -- coerce T1 K1 e, otherwise - -- - -- For example, in the initial form of a worker - -- we may find (coerce T (coerce S (\x.e))) y - -- and we'd like it to simplify to e[y/x] in one round - -- of simplification - | t1 `coreEqType` k1 = cont -- The coerces cancel out - | otherwise = CoerceIt t1 cont -- They don't cancel, but - -- the inner one is redundant - - addCoerce t1t2 s1s2 (ApplyTo dup arg mb_arg_se cont) - | not (isTypeArg arg), -- This whole case only works for value args - -- Could upgrade to have equiv thing for type apps too - Just (s1, s2) <- splitFunTy_maybe s1s2 - -- (coerce (T1->T2) (S1->S2) F) E - -- ===> - -- coerce T2 S2 (F (coerce S1 T1 E)) - -- - -- t1t2 must be a function type, T1->T2, because it's applied to something - -- but s1s2 might conceivably not be - -- - -- When we build the ApplyTo we can't mix the out-types - -- with the InExpr in the argument, so we simply substitute - -- to make it all consistent. It's a bit messy. - -- But it isn't a common case. - = let - (t1,t2) = splitFunTy t1t2 - new_arg = mkCoerce2 s1 t1 arg' - arg' = case mb_arg_se of - Nothing -> arg - Just arg_se -> substExpr (setInScope arg_se env) arg - in - ApplyTo dup new_arg Nothing (addCoerce t2 s2 cont) - - addCoerce to' _ cont = CoerceIt to' cont - in - simplType env to `thenSmpl` \ to' -> - simplType env from `thenSmpl` \ from' -> - simplExprF env body (addCoerce to' from' cont) -- Hack: we only distinguish subsumed cost centre stacks for the purposes of @@ -1249,7 +1260,7 @@ rebuild :: SimplEnv -> OutExpr -> SimplCont -> SimplM FloatsWithExpr rebuild env expr (Stop _ _ _) = rebuildDone env expr rebuild env expr (ArgOf _ _ _ cont_fn) = cont_fn env expr -rebuild env expr (CoerceIt to_ty cont) = rebuild env (mkCoerce to_ty expr) cont +rebuild env expr (CoerceIt co cont) = rebuild env (mkCoerce co expr) cont rebuild env expr (Select _ bndr alts se cont) = rebuildCase (setInScope se env) expr bndr alts cont rebuild env expr (ApplyTo _ arg mb_se cont) = rebuildApp env expr arg mb_se cont @@ -1505,6 +1516,7 @@ simplDefault :: SimplEnv simplDefault env case_bndr' imposs_cons cont Nothing = return [] -- No default branch + simplDefault env case_bndr' imposs_cons cont (Just rhs) | -- This branch handles the case where we are -- scrutinisng an algebraic data type @@ -1536,7 +1548,11 @@ simplDefault env case_bndr' imposs_cons cont (Just rhs) -- altogether if it can't match [con] -> -- It matches exactly one constructor, so fill it in - do { con_alt <- mkDataConAlt case_bndr' con inst_tys rhs + do { tick (FillInCaseDefault case_bndr') + ; us <- getUniquesSmpl + ; let (ex_tvs, co_tvs, arg_ids) = + dataConRepInstPat us con inst_tys + ; let con_alt = (DataAlt con, ex_tvs ++ co_tvs ++ arg_ids, rhs) ; Just (_, alt') <- simplAlt env [] case_bndr' cont con_alt -- The simplAlt must succeed with Just because we have -- already filtered out construtors that can't match @@ -1544,7 +1560,7 @@ simplDefault env case_bndr' imposs_cons cont (Just rhs) two_or_more -> simplify_default (map DataAlt gadt_imposs ++ imposs_cons) - | otherwise + | otherwise = simplify_default imposs_cons where cant_match tys data_con = not (dataConCanMatch data_con tys) @@ -1555,29 +1571,6 @@ simplDefault env case_bndr' imposs_cons cont (Just rhs) ; rhs' <- simplExprC env' rhs cont ; return [(DEFAULT, [], rhs')] } -mkDataConAlt :: Id -> DataCon -> [OutType] -> InExpr -> SimplM InAlt --- Make a data-constructor alternative to replace the DEFAULT case --- NB: there's something a bit bogus here, because we put OutTypes into an InAlt -mkDataConAlt case_bndr con tys rhs - = do { tick (FillInCaseDefault case_bndr) - ; args <- mk_args con tys - ; return (DataAlt con, args, rhs) } - where - mk_args con inst_tys - = do { (tv_bndrs, inst_tys') <- mk_tv_bndrs con inst_tys - ; let arg_tys = dataConInstArgTys con inst_tys' - ; arg_ids <- mapM (newId FSLIT("a")) arg_tys - ; returnSmpl (tv_bndrs ++ arg_ids) } - - mk_tv_bndrs con inst_tys - | isVanillaDataCon con - = return ([], inst_tys) - | otherwise - = do { tv_uniqs <- getUniquesSmpl - ; let new_tvs = zipWith mk tv_uniqs (dataConTyVars con) - mk uniq tv = mkTyVar (mkSysTvName uniq FSLIT("t")) (tyVarKind tv) - ; return (new_tvs, mkTyVarTys new_tvs) } - simplAlt :: SimplEnv -> [AltCon] -- These constructors can't be present when -- matching this alternative @@ -1612,7 +1605,6 @@ simplAlt env handled_cons case_bndr' cont' (LitAlt lit, bndrs, rhs) env' = mk_rhs_env env case_bndr' (mkUnfolding False (Lit lit)) simplAlt env handled_cons case_bndr' cont' (DataAlt con, vs, rhs) - | isVanillaDataCon con = -- Deal with the pattern-bound variables -- Mark the ones that are in ! positions in the data constructor -- as certainly-evaluated. @@ -1624,50 +1616,11 @@ simplAlt env handled_cons case_bndr' cont' (DataAlt con, vs, rhs) -- Bind the case-binder to (con args) let unf = mkUnfolding False (mkConApp con con_args) inst_tys' = tyConAppArgs (idType case_bndr') - con_args = map Type inst_tys' ++ map varToCoreExpr vs' + con_args = map Type inst_tys' ++ varsToCoreExprs vs' env' = mk_rhs_env env case_bndr' unf in simplExprC env' rhs cont' `thenSmpl` \ rhs' -> returnSmpl (Just (emptyVarEnv, (DataAlt con, vs', rhs'))) - - | otherwise -- GADT case - = let - (tvs,ids) = span isTyVar vs - in - simplBinders env tvs `thenSmpl` \ (env1, tvs') -> - case coreRefineTys con tvs' (idType case_bndr') of { - Nothing -- Inaccessible - | opt_PprStyle_Debug -- Hack: if debugging is on, generate an error case - -- so we can see it - -> let rhs' = mkApps (Var eRROR_ID) - [Type (substTy env (exprType rhs)), - Lit (mkStringLit "Impossible alternative (GADT)")] - in - simplBinders env1 ids `thenSmpl` \ (env2, ids') -> - returnSmpl (Just (emptyVarEnv, (DataAlt con, tvs' ++ ids', rhs'))) - - | otherwise -- Filter out the inaccessible branch - -> return Nothing ; - - Just refine@(tv_subst_env, _) -> -- The normal case - - let - env2 = refineSimplEnv env1 refine - -- Simplify the Ids in the refined environment, so their types - -- reflect the refinement. Usually this doesn't matter, but it helps - -- in mkDupableAlt, when we want to float a lambda that uses these binders - -- Furthermore, it means the binders contain maximal type information - in - simplBinders env2 (add_evals con ids) `thenSmpl` \ (env3, ids') -> - let unf = mkUnfolding False con_app - con_app = mkConApp con con_args - con_args = map varToCoreExpr vs' -- NB: no inst_tys' - env_w_unf = mk_rhs_env env3 case_bndr' unf - vs' = tvs' ++ ids' - in - simplExprC env_w_unf rhs cont' `thenSmpl` \ rhs' -> - returnSmpl (Just (tv_subst_env, (DataAlt con, vs', rhs'))) } - where -- add_evals records the evaluated-ness of the bound variables of -- a case pattern. This is *important*. Consider @@ -1743,7 +1696,7 @@ knownCon env scrut con args bndr alts cont simplExprF env rhs cont (DataAlt dc, bs, rhs) - -> ASSERT( n_drop_tys + length bs == length args ) + -> -- ASSERT( n_drop_tys + length bs == length args ) bind_args env dead_bndr bs (drop n_drop_tys args) $ \ env -> let -- It's useful to bind bndr to scrut, rather than to a fresh @@ -1763,10 +1716,8 @@ knownCon env scrut con args bndr alts cont simplNonRecX env bndr bndr_rhs $ \ env -> simplExprF env rhs cont where - dead_bndr = isDeadBinder bndr - n_drop_tys | isVanillaDataCon dc = tyConArity (dataConTyCon dc) - | otherwise = 0 - -- Vanilla data constructors lack type arguments in the pattern + dead_bndr = isDeadBinder bndr + n_drop_tys = tyConArity (dataConTyCon dc) -- Ugh! bind_args env dead_bndr [] _ thing_inside = thing_inside env @@ -2063,7 +2014,7 @@ mkDupableAlt env case_bndr' cont alt then newId FSLIT("w") realWorldStatePrimTy `thenSmpl` \ rw_id -> returnSmpl ([rw_id], [Var realWorldPrimId]) else - returnSmpl (used_bndrs', map varToCoreExpr used_bndrs') + returnSmpl (used_bndrs', varsToCoreExprs used_bndrs') ) `thenSmpl` \ (final_bndrs', final_args) -> -- See comment about "$j" name above