SimpleUnfolding(..), Unfolding(..), UnfoldingGuidance(..), -- types
UfExpr, RdrName, -- For closure (delete in 1.3)
- FormSummary(..), mkFormSummary, whnfOrBottom, exprSmallEnoughToDup,
+ FormSummary(..), mkFormSummary, whnfOrBottom, exprSmallEnoughToDup, exprIsTrivial,
noUnfolding, mkMagicUnfolding, mkUnfolding, getUnfoldingTemplate,
smallEnoughToInline, couldBeSmallEnoughToInline, certainlySmallEnoughToInline,
- okToInline,
+ inlineUnconditionally,
- calcUnfoldingGuidance
+ calcUnfoldingGuidance,
+
+ PragmaInfo(..) -- Re-export
) where
IMP_Ubiq()
+#if defined (__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 201
IMPORT_DELOOPER(IdLoop) -- for paranoia checking;
-- and also to get mkMagicUnfoldingFun
IMPORT_DELOOPER(PrelLoop) -- for paranoia checking
+IMPORT_DELOOPER(SmplLoop)
+#else
+import {-# SOURCE #-} MagicUFs
+#endif
import Bag ( emptyBag, unitBag, unionBags, Bag )
import CmdLineOpts ( opt_UnfoldingCreationThreshold,
opt_UnfoldingUseThreshold,
- opt_UnfoldingConDiscount
+ opt_UnfoldingConDiscount,
+ opt_UnfoldingKeenessFactor
)
import Constants ( uNFOLDING_CHEAP_OP_COST,
uNFOLDING_DEAR_OP_COST,
uNFOLDING_NOREP_LIT_COST
)
-import BinderInfo ( BinderInfo(..), FunOrArg, DuplicationDanger, InsideSCC, isDupDanger )
+import BinderInfo ( BinderInfo, isOneFunOcc, isOneSafeFunOcc
+ )
+import PragmaInfo ( PragmaInfo(..) )
import CoreSyn
import CoreUtils ( unTagBinders )
import HsCore ( UfExpr )
import RdrHsSyn ( RdrName )
import OccurAnal ( occurAnalyseGlobalExpr )
import CoreUtils ( coreExprType )
-import CostCentre ( ccMentionsId )
-import Id ( idType, getIdArity, isBottomingId, isDataCon, isPrimitiveId_maybe,
+--import CostCentre ( ccMentionsId )
+import Id ( SYN_IE(Id), idType, getIdArity, isBottomingId, isDataCon,
+ idWantsToBeINLINEd, idMustBeINLINEd, idMustNotBeINLINEd,
SYN_IE(IdSet), GenId{-instances-} )
import PrimOp ( primOpCanTriggerGC, fragilePrimOp, PrimOp(..) )
import IdInfo ( ArityInfo(..), bottomIsGuaranteed )
import Pretty
import TyCon ( tyConFamilySize )
import Type ( maybeAppDataTyConExpandingDicts )
+import Unique ( Unique )
import UniqSet ( emptyUniqSet, unitUniqSet, mkUniqSet,
addOneToUniqSet, unionUniqSets
)
import Usage ( SYN_IE(UVar) )
import Maybes ( maybeToBool )
import Util ( isIn, panic, assertPanic )
+#if __GLASGOW_HASKELL__ >= 202
+import Outputable
+#endif
\end{code}
%************************************************************************
noUnfolding = NoUnfolding
-mkUnfolding inline_me expr
+mkUnfolding inline_prag expr
= let
-- strictness mangling (depends on there being no CSE)
- ufg = calcUnfoldingGuidance inline_me opt_UnfoldingCreationThreshold expr
+ ufg = calcUnfoldingGuidance inline_prag opt_UnfoldingCreationThreshold expr
occ = occurAnalyseGlobalExpr expr
cuf = CoreUnfolding (SimpleUnfolding (mkFormSummary expr) ufg occ)
| UnfoldIfGoodArgs Int -- if "m" type args
Int -- and "n" value args
+
[Int] -- Discount if the argument is evaluated.
-- (i.e., a simplification will definitely
-- be possible). One elt of the list per *value* arg.
+
Int -- The "size" of the unfolding; to be elaborated
-- later. ToDo
+
+ Int -- Scrutinee discount: the discount to substract if the thing is in
+ -- a context (case (thing args) of ...),
+ -- (where there are the right number of arguments.)
\end{code}
\begin{code}
instance Outputable UnfoldingGuidance where
- ppr sty UnfoldAlways = ppPStr SLIT("_ALWAYS_")
--- ppr sty EssentialUnfolding = ppPStr SLIT("_ESSENTIAL_") -- shouldn't appear in an iface
- ppr sty (UnfoldIfGoodArgs t v cs size)
- = ppCat [ppPStr SLIT("_IF_ARGS_"), ppInt t, ppInt v,
+ ppr sty UnfoldAlways = ptext SLIT("_ALWAYS_")
+ ppr sty (UnfoldIfGoodArgs t v cs size discount)
+ = hsep [ptext SLIT("_IF_ARGS_"), int t, int v,
if null cs -- always print *something*
- then ppChar 'X'
- else ppBesides (map (ppStr . show) cs),
- ppInt size ]
+ then char 'X'
+ else hcat (map (text . show) cs),
+ int size,
+ int discount ]
\end{code}
| OtherForm -- Anything else
instance Outputable FormSummary where
- ppr sty VarForm = ppPStr SLIT("Var")
- ppr sty ValueForm = ppPStr SLIT("Value")
- ppr sty BottomForm = ppPStr SLIT("Bot")
- ppr sty OtherForm = ppPStr SLIT("Other")
+ ppr sty VarForm = ptext SLIT("Var")
+ ppr sty ValueForm = ptext SLIT("Value")
+ ppr sty BottomForm = ptext SLIT("Bot")
+ ppr sty OtherForm = ptext SLIT("Other")
mkFormSummary ::GenCoreExpr bndr Id tyvar uvar -> FormSummary
go n (Prim _ _) = OtherForm
go n (SCC _ e) = go n e
go n (Coerce _ _ e) = go n e
+
+ go n (Let (NonRec b r) e) | exprIsTrivial r = go n e -- let f = f' alpha in (f,g)
+ -- should be treated as a value
go n (Let _ e) = OtherForm
go n (Case _ _) = OtherForm
ArityAtLeast a | n < a -> ValueForm
other -> OtherForm
-whnfOrBottom :: GenCoreExpr bndr Id tyvar uvar -> Bool
-whnfOrBottom e = case mkFormSummary e of
- VarForm -> True
- ValueForm -> True
- BottomForm -> True
- OtherForm -> False
+whnfOrBottom :: FormSummary -> Bool
+whnfOrBottom VarForm = True
+whnfOrBottom ValueForm = True
+whnfOrBottom BottomForm = True
+whnfOrBottom OtherForm = False
\end{code}
+@exprIsTrivial@ is true of expressions we are unconditionally happy to duplicate;
+simple variables and constants, and type applications.
\begin{code}
-exprSmallEnoughToDup (Con _ _) = True -- Could check # of args
-exprSmallEnoughToDup (Prim op _) = not (fragilePrimOp op) -- Could check # of args
-exprSmallEnoughToDup (Lit lit) = not (isNoRepLit lit)
+exprIsTrivial (Var v) = True
+exprIsTrivial (Lit lit) = not (isNoRepLit lit)
+exprIsTrivial (App e (TyArg _)) = exprIsTrivial e
+exprIsTrivial (Coerce _ _ e) = exprIsTrivial e
+exprIsTrivial other = False
+\end{code}
+
+\begin{code}
+exprSmallEnoughToDup (Con _ _) = True -- Could check # of args
+exprSmallEnoughToDup (Prim op _) = not (fragilePrimOp op) -- Could check # of args
+exprSmallEnoughToDup (Lit lit) = not (isNoRepLit lit)
+exprSmallEnoughToDup (Coerce _ _ e) = exprSmallEnoughToDup e
exprSmallEnoughToDup expr
= case (collectArgs expr) of { (fun, _, _, vargs) ->
case fun of
- Var v | length vargs == 0 -> True
+ Var v | length vargs <= 4 -> True
_ -> False
}
-{- LATER:
-WAS: MORE CLEVER:
-exprSmallEnoughToDup expr -- for now, just: <var> applied to <args>
- = case (collectArgs expr) of { (fun, _, _, vargs) ->
- case fun of
- Var v -> v /= buildId
- && v /= augmentId
- && length vargs <= 6 -- or 10 or 1 or 4 or anything smallish.
- _ -> False
- }
--}
\end{code}
-Question (ADR): What is the above used for? Is a _ccall_ really small
-enough?
+
%************************************************************************
%* *
\begin{code}
calcUnfoldingGuidance
- :: Bool -- True <=> there's an INLINE pragma on this thing
+ :: PragmaInfo -- INLINE pragma stuff
-> Int -- bomb out if size gets bigger than this
-> CoreExpr -- expression to look at
-> UnfoldingGuidance
-calcUnfoldingGuidance True bOMB_OUT_SIZE expr = UnfoldAlways -- Always inline if the INLINE pragma says so
+calcUnfoldingGuidance IMustBeINLINEd bOMB_OUT_SIZE expr = UnfoldAlways -- Always inline if the INLINE pragma says so
+calcUnfoldingGuidance IWantToBeINLINEd bOMB_OUT_SIZE expr = UnfoldAlways -- Always inline if the INLINE pragma says so
+calcUnfoldingGuidance IMustNotBeINLINEd bOMB_OUT_SIZE expr = UnfoldNever -- ...and vice versa...
-calcUnfoldingGuidance False bOMB_OUT_SIZE expr
+calcUnfoldingGuidance NoPragmaInfo bOMB_OUT_SIZE expr
= case collectBinders expr of { (use_binders, ty_binders, val_binders, body) ->
case (sizeExpr bOMB_OUT_SIZE val_binders body) of
- Nothing -> UnfoldNever
+ TooBig -> UnfoldNever
- Just (size, cased_args)
+ SizeIs size cased_args scrut_discount
-> UnfoldIfGoodArgs
(length ty_binders)
(length val_binders)
(map discount_for val_binders)
- size
+ (I# size)
+ (I# scrut_discount)
where
discount_for b
| is_data && b `is_elem` cased_args = tyConFamilySize tycon
-> [Id] -- Arguments; we're interested in which of these
-- get case'd
-> CoreExpr
- -> Maybe (Int, -- Size
- [Id] -- Subset of args which are cased
- )
-
-sizeExpr bOMB_OUT_SIZE args expr
-
- | data_or_prim fun
--- We are very keen to inline literals, constructors, or primitives
--- including their slightly-disguised forms as applications (the latter
--- can show up in the bodies of things imported from interfaces).
- = Just (0, [])
+ -> ExprSize
- | otherwise
+sizeExpr (I# bOMB_OUT_SIZE) args expr
= size_up expr
where
- (fun, _) = splitCoreApps expr
- data_or_prim (Var v) = maybeToBool (isPrimitiveId_maybe v) ||
- isDataCon v
- data_or_prim (Con _ _) = True
- data_or_prim (Prim _ _) = True
- data_or_prim (Lit _) = True
- data_or_prim other = False
-
- size_up (Var v) = sizeZero
- size_up (App fun arg) = size_up fun `addSize` size_up_arg arg `addSizeN` 1
- -- 1 for application node
-
- size_up (Lit lit) = if isNoRepLit lit
- then sizeN uNFOLDING_NOREP_LIT_COST
- else sizeZero
-
--- I don't understand this hack so I'm removing it! SLPJ Nov 96
--- size_up (SCC _ (Con _ _)) = Nothing -- **** HACK *****
+ size_up (Var v) = sizeZero
+ size_up (Lit lit) | isNoRepLit lit = sizeN uNFOLDING_NOREP_LIT_COST
+ | otherwise = sizeZero
size_up (SCC lbl body) = size_up body -- SCCs cost nothing
size_up (Coerce _ _ body) = size_up body -- Coercions cost nothing
- size_up (Con con args) = sizeN (numValArgs args)
+ size_up (App fun arg) = size_up fun `addSize` size_up_arg arg
+ -- NB Zero cost for for type applications;
+ -- others cost 1 or more
+
+ size_up (Con con args) = conSizeN (numValArgs args)
-- We don't count 1 for the constructor because we're
-- quite keen to get constructors into the open
size_up body `addSizeN` length args
size_up (Let (NonRec binder rhs) body)
- = size_up rhs
+ = nukeScrutDiscount (size_up rhs)
`addSize`
size_up body
- `addSizeN`
- 1
size_up (Let (Rec pairs) body)
- = foldr addSize sizeZero [size_up rhs | (_,rhs) <- pairs]
+ = nukeScrutDiscount (foldr addSize sizeZero [size_up rhs | (_,rhs) <- pairs])
`addSize`
size_up body
- `addSizeN`
- length pairs
size_up (Case scrut alts)
- = size_up_scrut scrut
+ = nukeScrutDiscount (size_up scrut)
+ `addSize`
+ arg_discount scrut
`addSize`
size_up_alts (coreExprType scrut) alts
-- We charge for the "case" itself in "size_up_alts"
------------
+ -- In an application we charge 0 for type application
+ -- 1 for most anything else
+ -- N for norep_lits
size_up_arg (LitArg lit) | isNoRepLit lit = sizeN uNFOLDING_NOREP_LIT_COST
- size_up_arg other = sizeZero
+ size_up_arg (TyArg _) = sizeZero
+ size_up_arg other = sizeOne
------------
size_up_alts scrut_ty (AlgAlts alts deflt)
- = foldr (addSize . size_alg_alt) (size_up_deflt deflt) alts
+ = (foldr (addSize . size_alg_alt) (size_up_deflt deflt) alts)
`addSizeN`
alt_cost
where
alt_cost :: Int
alt_cost
- = --trace "CoreUnfold.getAppDataTyConExpandingDicts:2" $
- case (maybeAppDataTyConExpandingDicts scrut_ty) of
+ = case (maybeAppDataTyConExpandingDicts scrut_ty) of
Nothing -> 1
Just (tc,_,_) -> tyConFamilySize tc
size_prim_alt (lit,rhs) = size_up rhs
------------
- size_up_deflt NoDefault = sizeZero
+ size_up_deflt NoDefault = sizeZero
size_up_deflt (BindDefault binder rhs) = size_up rhs
------------
- -- Scrutinees. There are two things going on here.
- -- First, we want to record if we're case'ing an argument
- -- Second, we want to charge nothing for the srutinee if it's just
- -- a variable. That way wrapper-like things look cheap.
- size_up_scrut (Var v) | v `is_elem` args = Just (0, [v])
- | otherwise = Just (0, [])
- size_up_scrut other = size_up other
+ -- We want to record if we're case'ing an argument
+ arg_discount (Var v) | v `is_elem` args = scrutArg v
+ arg_discount other = sizeZero
is_elem :: Id -> [Id] -> Bool
is_elem = isIn "size_up_scrut"
------------
- sizeZero = Just (0, [])
- sizeOne = Just (1, [])
- sizeN n = Just (n, [])
-
- addSizeN Nothing _ = Nothing
- addSizeN (Just (n, xs)) m
- | tot < bOMB_OUT_SIZE = Just (tot, xs)
- | otherwise = Nothing
- where
- tot = n+m
+ -- These addSize things have to be here because
+ -- I don't want to give them bOMB_OUT_SIZE as an argument
- addSize Nothing _ = Nothing
- addSize _ Nothing = Nothing
- addSize (Just (n, xs)) (Just (m, ys))
- | tot < bOMB_OUT_SIZE = Just (tot, xys)
- | otherwise = Nothing
+ addSizeN TooBig _ = TooBig
+ addSizeN (SizeIs n xs d) (I# m)
+ | n_tot -# d <# bOMB_OUT_SIZE = SizeIs n_tot xs d
+ | otherwise = TooBig
+ where
+ n_tot = n +# m
+
+ addSize TooBig _ = TooBig
+ addSize _ TooBig = TooBig
+ addSize (SizeIs n1 xs d1) (SizeIs n2 ys d2)
+ | (n_tot -# d_tot) <# bOMB_OUT_SIZE = SizeIs n_tot xys d_tot
+ | otherwise = TooBig
where
- tot = n+m
- xys = xs ++ ys
+ n_tot = n1 +# n2
+ d_tot = d1 +# d2
+ xys = xs ++ ys
-splitCoreApps e
- = go e []
- where
- go (App fun arg) args = go fun (arg:args)
- go fun args = (fun,args)
+
+\end{code}
+
+Code for manipulating sizes
+
+\begin{code}
+
+data ExprSize = TooBig
+ | SizeIs Int# -- Size found
+ [Id] -- Arguments cased herein
+ Int# -- Size to subtract if result is scrutinised
+ -- by a case expression
+
+sizeZero = SizeIs 0# [] 0#
+sizeOne = SizeIs 1# [] 0#
+sizeN (I# n) = SizeIs n [] 0#
+conSizeN (I# n) = SizeIs n [] n
+scrutArg v = SizeIs 0# [v] 0#
+
+nukeScrutDiscount (SizeIs n vs d) = SizeIs n vs 0#
+nukeScrutDiscount TooBig = TooBig
\end{code}
%************************************************************************
a single integer. (3)~An ``argument info'' vector. For this, what we
have at the moment is a Boolean per argument position that says, ``I
will look with great favour on an explicit constructor in this
-position.''
+position.'' (4)~The ``discount'' to subtract if the expression
+is being scrutinised.
Assuming we have enough type- and value arguments (if not, we give up
immediately), then we see if the ``discounted size'' is below some
hands, we get a (again, semi-arbitrary) discount [proportion to the
number of constructors in the type being scrutinized].
+If we're in the context of a scrutinee ( \tr{(case <expr > of A .. -> ...;.. )})
+and the expression in question will evaluate to a constructor, we use
+the computed discount size *for the result only* rather than
+computing the argument discounts. Since we know the result of
+the expression is going to be taken apart, discounting its size
+is more accurate (see @sizeExpr@ above for how this discount size
+is computed).
+
\begin{code}
smallEnoughToInline :: [Bool] -- Evaluated-ness of value arguments
+ -> Bool -- Result is scrutinised
-> UnfoldingGuidance
-> Bool -- True => unfold it
-smallEnoughToInline _ UnfoldAlways = True
-smallEnoughToInline _ UnfoldNever = False
-smallEnoughToInline arg_is_evald_s
- (UnfoldIfGoodArgs m_tys_wanted n_vals_wanted discount_vec size)
+smallEnoughToInline _ _ UnfoldAlways = True
+smallEnoughToInline _ _ UnfoldNever = False
+smallEnoughToInline arg_is_evald_s result_is_scruted
+ (UnfoldIfGoodArgs m_tys_wanted n_vals_wanted discount_vec size scrut_discount)
= enough_args n_vals_wanted arg_is_evald_s &&
- discounted_size <= opt_UnfoldingUseThreshold
+ size - discount <= opt_UnfoldingUseThreshold
where
- enough_args 0 evals = True
- enough_args n [] = False
- enough_args n (e:es) = enough_args (n-1) es
- -- NB: don't take the length of arg_is_evald_s because when
- -- called from couldBeSmallEnoughToInline it is infinite!
- discounted_size = size - sum (zipWith arg_discount discount_vec arg_is_evald_s)
+ enough_args n [] | n > 0 = False -- A function with no value args => don't unfold
+ enough_args _ _ = True -- Otherwise it's ok to try
+
+ -- We multiple the raw discounts (args_discount and result_discount)
+ -- ty opt_UnfoldingKeenessFactor because the former have to do with
+ -- *size* whereas the discounts imply that there's some extra *efficiency*
+ -- to be gained (e.g. beta reductions, case reductions) by inlining.
+ discount :: Int
+ discount = round (
+ opt_UnfoldingKeenessFactor *
+ fromInt (args_discount + result_discount)
+ )
+
+ args_discount = sum (zipWith arg_discount discount_vec arg_is_evald_s)
+ result_discount | result_is_scruted = scrut_discount
+ | otherwise = 0
arg_discount no_of_constrs is_evald
| is_evald = 1 + no_of_constrs * opt_UnfoldingConDiscount
Just the same as smallEnoughToInline, except that it has no actual arguments.
\begin{code}
+--UNUSED?
couldBeSmallEnoughToInline :: UnfoldingGuidance -> Bool
-couldBeSmallEnoughToInline guidance = smallEnoughToInline (repeat True) guidance
+couldBeSmallEnoughToInline guidance = smallEnoughToInline (repeat True) True guidance
certainlySmallEnoughToInline :: UnfoldingGuidance -> Bool
-certainlySmallEnoughToInline guidance = smallEnoughToInline (repeat False) guidance
+certainlySmallEnoughToInline guidance = smallEnoughToInline (repeat False) False guidance
\end{code}
Predicates
~~~~~~~~~~
+@inlineUnconditionally@ decides whether a let-bound thing can
+*definitely* be inlined at each of its call sites. If so, then
+we can drop the binding right away. But remember, you have to be
+certain that every use can be inlined. So, notably, any ArgOccs
+rule this out. Since ManyOcc doesn't record FunOcc/ArgOcc
+
\begin{code}
-okToInline
- :: FormSummary -- What the thing to be inlined is like
- -> BinderInfo -- How the thing to be inlined occurs
- -> Bool -- True => it's small enough to inline
- -> Bool -- True => yes, inline it
-
--- If there's no danger of duplicating work, we can inline if it occurs once, or is small
-okToInline form occ_info small_enough
- | no_dup_danger form
- = small_enough || one_occ
- where
- one_occ = case occ_info of
- OneOcc _ _ _ n_alts _ -> n_alts <= 1
- other -> False
-
- no_dup_danger VarForm = True
- no_dup_danger ValueForm = True
- no_dup_danger BottomForm = True
- no_dup_danger other = False
-
--- A non-WHNF can be inlined if it doesn't occur inside a lambda,
--- and occurs exactly once or
--- occurs once in each branch of a case and is small
-okToInline OtherForm (OneOcc _ dup_danger _ n_alts _) small_enough
- = not (isDupDanger dup_danger) && (n_alts <= 1 || small_enough)
+inlineUnconditionally :: Bool -> Id -> BinderInfo -> Bool
-okToInline form any_occ small_enough = False
-\end{code}
+inlineUnconditionally ok_to_dup id occ_info
+ | idMustNotBeINLINEd id = False
+
+ | isOneFunOcc occ_info
+ && idMustBeINLINEd id = True
+ | isOneSafeFunOcc (ok_to_dup || idWantsToBeINLINEd id) occ_info
+ = True
+
+ | otherwise
+ = False
+\end{code}
projects / ghc-hetmet.git / blobdiff