X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FSetLevels.lhs;h=9726aa68a0d2b44b9ae231a380297536877b1ee1;hb=432b9c9322181a3644083e3c19b7e240d90659e7;hp=fb9ca7f5953ca870dbe2fc17eab44a6e01a93286;hpb=27061b5b4008a831eba4784358b040bb1250dcef;p=ghc-hetmet.git diff --git a/compiler/simplCore/SetLevels.lhs b/compiler/simplCore/SetLevels.lhs index fb9ca7f..9726aa6 100644 --- a/compiler/simplCore/SetLevels.lhs +++ b/compiler/simplCore/SetLevels.lhs @@ -42,13 +42,6 @@ the scrutinee of the case, and we can inline it. \begin{code} -{-# OPTIONS -w #-} --- 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 SetLevels ( setLevels, @@ -71,9 +64,7 @@ import Id ( Id, idType, mkSysLocal, isOneShotLambda, zapDemandIdInfo, transferPolyIdInfo, idSpecialisation, idWorkerInfo, setIdInfo ) -import IdInfo ( workerExists, vanillaIdInfo, isEmptySpecInfo, - setNewStrictnessInfo, newStrictnessInfo, - setArityInfo, arityInfo ) +import IdInfo import Var import VarSet import VarEnv @@ -159,14 +150,15 @@ the worker at all. type LevelledExpr = TaggedExpr Level type LevelledBind = TaggedBind Level +tOP_LEVEL, iNLINE_CTXT :: Level tOP_LEVEL = Level 0 0 iNLINE_CTXT = InlineCtxt incMajorLvl :: Level -> Level -- For InlineCtxt we ignore any inc's; we don't want -- to do any floating at all; see notes above -incMajorLvl InlineCtxt = InlineCtxt -incMajorLvl (Level major minor) = Level (major+1) 0 +incMajorLvl InlineCtxt = InlineCtxt +incMajorLvl (Level major _) = Level (major + 1) 0 incMinorLvl :: Level -> Level incMinorLvl InlineCtxt = InlineCtxt @@ -180,33 +172,33 @@ maxLvl l1@(Level maj1 min1) l2@(Level maj2 min2) | otherwise = l2 ltLvl :: Level -> Level -> Bool -ltLvl any_lvl InlineCtxt = False +ltLvl _ InlineCtxt = False ltLvl InlineCtxt (Level _ _) = True ltLvl (Level maj1 min1) (Level maj2 min2) = (maj1 < maj2) || (maj1 == maj2 && min1 < min2) ltMajLvl :: Level -> Level -> Bool -- Tells if one level belongs to a difft *lambda* level to another -ltMajLvl any_lvl InlineCtxt = False -ltMajLvl InlineCtxt (Level maj2 _) = 0 < maj2 +ltMajLvl _ InlineCtxt = False +ltMajLvl InlineCtxt (Level maj2 _) = 0 < maj2 ltMajLvl (Level maj1 _) (Level maj2 _) = maj1 < maj2 isTopLvl :: Level -> Bool isTopLvl (Level 0 0) = True -isTopLvl other = False +isTopLvl _ = False isInlineCtxt :: Level -> Bool isInlineCtxt InlineCtxt = True -isInlineCtxt other = False +isInlineCtxt _ = False instance Outputable Level where ppr InlineCtxt = text "" ppr (Level maj min) = hcat [ char '<', int maj, char ',', int min, char '>' ] instance Eq Level where - InlineCtxt == InlineCtxt = True - (Level maj1 min1) == (Level maj2 min2) = maj1==maj2 && min1==min2 - l1 == l2 = False + InlineCtxt == InlineCtxt = True + (Level maj1 min1) == (Level maj2 min2) = maj1 == maj2 && min1 == min2 + _ == _ = False \end{code} @@ -238,6 +230,7 @@ setLevels float_lams binds us init_env = initialEnv float_lams +lvlTopBind :: LevelEnv -> Bind Id -> LvlM (LevelledBind, LevelEnv) lvlTopBind env (NonRec binder rhs) = lvlBind TopLevel tOP_LEVEL env (AnnNonRec binder (freeVars rhs)) -- Rhs can have no free vars! @@ -275,9 +268,9 @@ don't want @lvlExpr@ to turn the scrutinee of the @case@ into an MFE If there were another lambda in @r@'s rhs, it would get level-2 as well. \begin{code} -lvlExpr _ _ (_, AnnType ty) = return (Type ty) +lvlExpr _ _ ( _, AnnType ty) = return (Type ty) lvlExpr _ env (_, AnnVar v) = return (lookupVar env v) -lvlExpr _ env (_, AnnLit lit) = return (Lit lit) +lvlExpr _ _ (_, AnnLit lit) = return (Lit lit) lvlExpr ctxt_lvl env (_, AnnApp fun arg) = do fun' <- lvl_fun fun @@ -286,11 +279,11 @@ lvlExpr ctxt_lvl env (_, AnnApp fun arg) = do where -- gaw 2004 lvl_fun (_, AnnCase _ _ _ _) = lvlMFE True ctxt_lvl env fun - lvl_fun other = lvlExpr ctxt_lvl env fun + lvl_fun _ = lvlExpr ctxt_lvl env fun -- We don't do MFE on partial applications generally, -- but we do if the function is big and hairy, like a case -lvlExpr ctxt_lvl env (_, AnnNote InlineMe expr) = do +lvlExpr _ env (_, AnnNote InlineMe expr) = do -- Don't float anything out of an InlineMe; hence the iNLINE_CTXT expr' <- lvlExpr iNLINE_CTXT env expr return (Note InlineMe expr') @@ -310,7 +303,7 @@ lvlExpr ctxt_lvl env (_, AnnCast expr co) = do -- Why not? Because partial applications are fairly rare, and splitting -- lambdas makes them more expensive. -lvlExpr ctxt_lvl env expr@(_, AnnLam bndr rhs) = do +lvlExpr ctxt_lvl env expr@(_, AnnLam {}) = do new_body <- lvlMFE True new_lvl new_env body return (mkLams new_bndrs new_body) where @@ -365,13 +358,22 @@ lvlExpr ctxt_lvl env (_, AnnCase expr case_bndr ty alts) = do @lvlMFE@ is just like @lvlExpr@, except that it might let-bind the expression, so that it can itself be floated. -[NOTE: unlifted MFEs] +Note [Unlifted MFEs] +~~~~~~~~~~~~~~~~~~~~~ We don't float unlifted MFEs, which potentially loses big opportunites. For example: \x -> f (h y) where h :: Int -> Int# is expensive. We'd like to float the (h y) outside the \x, but we don't because it's unboxed. Possible solution: box it. +Note [Case MFEs] +~~~~~~~~~~~~~~~~ +We don't float a case expression as an MFE from a strict context. Why not? +Because in doing so we share a tiny bit of computation (the switch) but +in exchange we build a thunk, which is bad. This case reduces allocation +by 7% in spectral/puzzle (a rather strange benchmark) and 1.2% in real/fem. +Doesn't change any other allocation at all. + \begin{code} lvlMFE :: Bool -- True <=> strict context [body of case or let] -> Level -- Level of innermost enclosing lambda/tylam @@ -379,12 +381,23 @@ lvlMFE :: Bool -- True <=> strict context [body of case or let] -> CoreExprWithFVs -- input expression -> LvlM LevelledExpr -- Result expression -lvlMFE strict_ctxt ctxt_lvl env (_, AnnType ty) +lvlMFE _ _ _ (_, AnnType ty) = return (Type ty) +-- No point in floating out an expression wrapped in a coercion; +-- If we do we'll transform lvl = e |> co +-- to lvl' = e; lvl = lvl' |> co +-- and then inline lvl. Better just to float out the payload. +lvlMFE strict_ctxt ctxt_lvl env (_, AnnCast e co) + = do { expr' <- lvlMFE strict_ctxt ctxt_lvl env e + ; return (Cast expr' co) } + +-- Note [Case MFEs] +lvlMFE True ctxt_lvl env e@(_, AnnCase {}) + = lvlExpr ctxt_lvl env e -- Don't share cases lvlMFE strict_ctxt ctxt_lvl env ann_expr@(fvs, _) - | isUnLiftedType ty -- Can't let-bind it; see [NOTE: unlifted MFEs] + | isUnLiftedType ty -- Can't let-bind it; see Note [Unlifted MFEs] || isInlineCtxt ctxt_lvl -- Don't float out of an __inline__ context || exprIsTrivial expr -- Never float if it's trivial || not good_destination @@ -488,7 +501,9 @@ lvlBind :: TopLevelFlag -- Used solely to decide whether to clone -> LvlM (LevelledBind, LevelEnv) lvlBind top_lvl ctxt_lvl env (AnnNonRec bndr rhs@(rhs_fvs,_)) - | isInlineCtxt ctxt_lvl -- Don't do anything inside InlineMe + | isTyVar bndr -- Don't do anything for TyVar binders + -- (simplifier gets rid of them pronto) + || isInlineCtxt ctxt_lvl -- Don't do anything inside InlineMe = do rhs' <- lvlExpr ctxt_lvl env rhs return (NonRec (TB bndr ctxt_lvl) rhs', env) @@ -571,6 +586,8 @@ lvlBind top_lvl ctxt_lvl env (AnnRec pairs) ---------------------------------------------------- -- Three help functons for the type-abstraction case +lvlFloatRhs :: [CoreBndr] -> Level -> LevelEnv -> CoreExprWithFVs + -> UniqSM (Expr (TaggedBndr Level)) lvlFloatRhs abs_vars dest_lvl env rhs = do rhs' <- lvlExpr rhs_lvl rhs_env rhs return (mkLams abs_vars_w_lvls rhs') @@ -600,7 +617,7 @@ lvlLamBndrs lvl bndrs [] bndrs where go old_lvl bumped_major rev_lvld_bndrs (bndr:bndrs) - | isId bndr && -- Go to the next major level if this is a value binder, + | isId bndr && -- Go to the next major level if this is a value binder, not bumped_major && -- and we havn't already gone to the next level (one jump per group) not (isOneShotLambda bndr) -- and it isn't a one-shot lambda = go new_lvl True (TB bndr new_lvl : rev_lvld_bndrs) bndrs @@ -643,9 +660,9 @@ isFunction :: CoreExprWithFVs -> Bool -- variables. We certainly only want to do it for values, and not for -- constructors. So the simple thing is just to look for lambdas isFunction (_, AnnLam b e) | isId b = True - | otherwise = isFunction e -isFunction (_, AnnNote n e) = isFunction e -isFunction other = False + | otherwise = isFunction e +isFunction (_, AnnNote _ e) = isFunction e +isFunction _ = False \end{code} @@ -686,10 +703,10 @@ initialEnv :: FloatOutSwitches -> LevelEnv initialEnv float_lams = (float_lams, emptyVarEnv, emptySubst, emptyVarEnv) floatLams :: LevelEnv -> Bool -floatLams (FloatOutSw float_lams _, _, _, _) = float_lams +floatLams (fos, _, _, _) = floatOutLambdas fos floatConsts :: LevelEnv -> Bool -floatConsts (FloatOutSw _ float_consts, _, _, _) = float_consts +floatConsts (fos, _, _, _) = floatOutConstants fos extendLvlEnv :: LevelEnv -> [TaggedBndr Level] -> LevelEnv -- Used when *not* cloning @@ -718,33 +735,37 @@ extendLvlEnv (float_lams, lvl_env, subst, id_env) prs -- extendCaseBndrLvlEnv adds the mapping case-bndr->scrut-var if it can -- (see point 4 of the module overview comment) +extendCaseBndrLvlEnv :: LevelEnv -> Expr (TaggedBndr Level) -> Var -> Level + -> LevelEnv extendCaseBndrLvlEnv (float_lams, lvl_env, subst, id_env) (Var scrut_var) case_bndr lvl = (float_lams, extendVarEnv lvl_env case_bndr lvl, extendIdSubst subst case_bndr (Var scrut_var), extendVarEnv id_env case_bndr ([scrut_var], Var scrut_var)) -extendCaseBndrLvlEnv env scrut case_bndr lvl +extendCaseBndrLvlEnv env _scrut case_bndr lvl = extendLvlEnv env [TB case_bndr lvl] +extendPolyLvlEnv :: Level -> LevelEnv -> [Var] -> [(Var, Var)] -> LevelEnv extendPolyLvlEnv dest_lvl (float_lams, lvl_env, subst, id_env) abs_vars bndr_pairs = (float_lams, foldl add_lvl lvl_env bndr_pairs, foldl add_subst subst bndr_pairs, foldl add_id id_env bndr_pairs) where - add_lvl env (v,v') = extendVarEnv env v' dest_lvl - add_subst env (v,v') = extendIdSubst env v (mkVarApps (Var v') abs_vars) - add_id env (v,v') = extendVarEnv env v ((v':abs_vars), mkVarApps (Var v') abs_vars) + add_lvl env (_, v') = extendVarEnv env v' dest_lvl + add_subst env (v, v') = extendIdSubst env v (mkVarApps (Var v') abs_vars) + add_id env (v, v') = extendVarEnv env v ((v':abs_vars), mkVarApps (Var v') abs_vars) +extendCloneLvlEnv :: Level -> LevelEnv -> Subst -> [(Var, Var)] -> LevelEnv extendCloneLvlEnv lvl (float_lams, lvl_env, _, id_env) new_subst bndr_pairs = (float_lams, foldl add_lvl lvl_env bndr_pairs, new_subst, foldl add_id id_env bndr_pairs) where - add_lvl env (v,v') = extendVarEnv env v' lvl - add_id env (v,v') = extendVarEnv env v ([v'], Var v') + add_lvl env (_, v') = extendVarEnv env v' lvl + add_id env (v, v') = extendVarEnv env v ([v'], Var v') maxIdLevel :: LevelEnv -> VarSet -> Level @@ -764,7 +785,7 @@ maxIdLevel (_, lvl_env,_,id_env) var_set lookupVar :: LevelEnv -> Id -> LevelledExpr lookupVar (_, _, _, id_env) v = case lookupVarEnv id_env v of Just (_, expr) -> expr - other -> Var v + _ -> Var v abstractVars :: Level -> LevelEnv -> VarSet -> [Var] -- Find the variables in fvs, free vars of the target expresion, @@ -783,7 +804,7 @@ abstractVars dest_lvl (_, lvl_env, _, id_env) fvs v1 `le` v2 = case (is_tv v1, is_tv v2) of (True, False) -> True (False, True) -> False - other -> v1 <= v2 -- Same family + _ -> v1 <= v2 -- Same family is_tv v = isTyVar v && not (isCoVar v) @@ -830,17 +851,19 @@ absVarsOf id_env v \begin{code} type LvlM result = UniqSM result -initLvl = initUs_ +initLvl :: UniqSupply -> UniqSM a -> a +initLvl = initUs_ \end{code} \begin{code} +newPolyBndrs :: Level -> LevelEnv -> [Var] -> [Id] -> UniqSM (LevelEnv, [Id]) newPolyBndrs dest_lvl env abs_vars bndrs = do uniqs <- getUniquesM let new_bndrs = zipWith mk_poly_bndr bndrs uniqs return (extendPolyLvlEnv dest_lvl env abs_vars (bndrs `zip` new_bndrs), new_bndrs) where - mk_poly_bndr bndr uniq = transferPolyIdInfo bndr $ -- Note [transferPolyIdInfo] in Id.lhs + mk_poly_bndr bndr uniq = transferPolyIdInfo bndr abs_vars $ -- Note [transferPolyIdInfo] in Id.lhs mkSysLocal (mkFastString str) uniq poly_ty where str = "poly_" ++ occNameString (getOccName bndr) @@ -857,7 +880,7 @@ newLvlVar str vars body_ty = do -- to the rules inside each Id. Grr. But it matters. cloneVar :: TopLevelFlag -> LevelEnv -> Id -> Level -> Level -> LvlM (LevelEnv, Id) -cloneVar TopLevel env v ctxt_lvl dest_lvl +cloneVar TopLevel env v _ _ = return (env, v) -- Don't clone top level things cloneVar NotTopLevel env@(_,_,subst,_) v ctxt_lvl dest_lvl = ASSERT( isId v ) do @@ -869,7 +892,7 @@ cloneVar NotTopLevel env@(_,_,subst,_) v ctxt_lvl dest_lvl return (env', v2) cloneRecVars :: TopLevelFlag -> LevelEnv -> [Id] -> Level -> Level -> LvlM (LevelEnv, [Id]) -cloneRecVars TopLevel env vs ctxt_lvl dest_lvl +cloneRecVars TopLevel env vs _ _ = return (env, vs) -- Don't clone top level things cloneRecVars NotTopLevel env@(_,_,subst,_) vs ctxt_lvl dest_lvl = ASSERT( all isId vs ) do @@ -883,6 +906,7 @@ cloneRecVars NotTopLevel env@(_,_,subst,_) vs ctxt_lvl dest_lvl -- VERY IMPORTANT: we must zap the demand info -- if the thing is going to float out past a lambda, -- or if it's going to top level (where things can't be strict) +zap_demand :: Level -> Level -> Id -> Id zap_demand dest_lvl ctxt_lvl id | ctxt_lvl == dest_lvl, not (isTopLvl dest_lvl) = id -- Stays, and not going to top level