mkOtherCon, otherCons,
unfoldingTemplate, maybeUnfoldingTemplate,
isEvaldUnfolding, isValueUnfolding, isCheapUnfolding, isCompulsoryUnfolding,
- hasUnfolding, hasSomeUnfolding,
+ hasUnfolding, hasSomeUnfolding, neverUnfold,
couldBeSmallEnoughToInline,
certainlyWillInline,
okToUnfoldInHiFile,
- callSiteInline, blackListed
+ callSiteInline
) where
#include "HsVersions.h"
import CmdLineOpts ( opt_UF_CreationThreshold,
opt_UF_UseThreshold,
- opt_UF_ScrutConDiscount,
opt_UF_FunAppDiscount,
- opt_UF_PrimArgDiscount,
- opt_UF_KeenessFactor,
- opt_UF_CheapOp, opt_UF_DearOp,
- opt_UnfoldCasms, opt_PprStyle_Debug,
- opt_D_dump_inlinings
+ opt_UF_KeenessFactor,
+ opt_UF_DearOp, opt_UnfoldCasms,
+ DynFlags, DynFlag(..), dopt
)
import CoreSyn
import PprCore ( pprCoreExpr )
import OccurAnal ( occurAnalyseGlobalExpr )
-import BinderInfo ( )
-import CoreUtils ( exprIsValue, exprIsCheap, exprIsBottom, exprIsTrivial )
-import Id ( Id, idType, idFlavour, idUnique, isId, idWorkerInfo,
- idSpecialisation, idInlinePragma, idUnfolding,
- isPrimOpId_maybe
+import CoreUtils ( exprIsValue, exprIsCheap, exprIsTrivial )
+import Id ( Id, idType, isId,
+ idUnfolding,
+ isFCallId_maybe, globalIdDetails
)
-import VarSet
-import Name ( isLocallyDefined )
-import Literal ( isLitLitLit )
-import PrimOp ( PrimOp(..), primOpIsDupable, primOpOutOfLine, ccallIsCasm )
-import IdInfo ( ArityInfo(..), InlinePragInfo(..), OccInfo(..), IdFlavour(..), CprInfo(..),
- insideLam, workerExists, isNeverInlinePrag
- )
-import TyCon ( tyConFamilySize )
-import Type ( splitFunTy_maybe, isUnLiftedType )
-import Unique ( Unique, buildIdKey, augmentIdKey )
-import Maybes ( maybeToBool )
+import DataCon ( isUnboxedTupleCon )
+import Literal ( isLitLitLit, litSize )
+import PrimOp ( primOpIsDupable, primOpOutOfLine )
+import ForeignCall ( okToExposeFCall )
+import IdInfo ( OccInfo(..), GlobalIdDetails(..) )
+import Type ( isUnLiftedType )
+import PrelNames ( hasKey, buildIdKey, augmentIdKey )
import Bag
-import List ( maximumBy )
-import Util ( isIn, lengthExceeds )
+import FastTypes
import Outputable
+import Util
#if __GLASGOW_HASKELL__ >= 404
-import GlaExts ( fromInt )
+import GLAEXTS ( Int# )
#endif
\end{code}
mkUnfolding top_lvl expr
= CoreUnfolding (occurAnalyseGlobalExpr expr)
top_lvl
- (exprIsCheap expr)
+
(exprIsValue expr)
- (exprIsBottom expr)
+ -- Already evaluated
+
+ (exprIsCheap expr)
+ -- OK to inline inside a lambda
+
(calcUnfoldingGuidance opt_UF_CreationThreshold expr)
-- Sometimes during simplification, there's a large let-bound thing
-- which has been substituted, and so is now dead; so 'expr' contains
-- but no more.
in
- case (sizeExpr bOMB_OUT_SIZE val_binders body) of
+ case (sizeExpr (iUnbox bOMB_OUT_SIZE) val_binders body) of
TooBig
| not inline -> UnfoldNever
n_val_binders
(map discount_for val_binders)
final_size
- (I# scrut_discount)
+ (iBox scrut_discount)
where
- boxed_size = I# size
+ boxed_size = iBox size
final_size | inline = boxed_size `min` max_inline_size
| otherwise = boxed_size
\end{code}
\begin{code}
-sizeExpr :: Int -- Bomb out if it gets bigger than this
+sizeExpr :: Int# -- Bomb out if it gets bigger than this
-> [Id] -- Arguments; we're interested in which of these
-- get case'd
-> CoreExpr
-> ExprSize
-sizeExpr (I# bOMB_OUT_SIZE) top_args expr
+sizeExpr bOMB_OUT_SIZE top_args expr
= size_up expr
where
size_up (Type t) = sizeZero -- Types cost nothing
size_up (Var v) = sizeOne
- size_up (Note _ body) = size_up body -- Notes cost nothing
+ size_up (Note InlineMe body) = sizeOne -- Inline notes make it look very small
+ -- This can be important. If you have an instance decl like this:
+ -- instance Foo a => Foo [a] where
+ -- {-# INLINE op1, op2 #-}
+ -- op1 = ...
+ -- op2 = ...
+ -- then we'll get a dfun which is a pair of two INLINE lambdas
- size_up (App fun (Type t)) = size_up fun
- size_up (App fun arg) = size_up_app fun [arg]
+ size_up (Note _ body) = size_up body -- Other notes cost nothing
- size_up (Lit lit) = sizeOne
+ size_up (App fun (Type t)) = size_up fun
+ size_up (App fun arg) = size_up_app fun [arg]
+
+ size_up (Lit lit) = sizeN (litSize lit)
size_up (Lam b e) | isId b = lamScrutDiscount (size_up e `addSizeN` 1)
| otherwise = size_up e
where
rhs_size = foldr (addSize . size_up . snd) sizeZero pairs
- -- We want to make wrapper-style evaluation look cheap, so that
- -- when we inline a wrapper it doesn't make call site (much) bigger
- -- Otherwise we get nasty phase ordering stuff:
- -- f x = g x x
- -- h y = ...(f e)...
- -- If we inline g's wrapper, f looks big, and doesn't get inlined
- -- into h; if we inline f first, while it looks small, then g's
- -- wrapper will get inlined later anyway. To avoid this nasty
- -- ordering difference, we make (case a of (x,y) -> ...) look free.
- size_up (Case (Var v) _ [alt])
- | v `elem` top_args
- = size_up_alt alt `addSize` SizeIs 0# (unitBag (v, 1)) 0#
+ size_up (Case (Var v) _ alts)
+ | v `elem` top_args -- We are scrutinising an argument variable
+ =
+{- I'm nuking this special case; BUT see the comment with case alternatives.
+
+ (a) It's too eager. We don't want to inline a wrapper into a
+ context with no benefit.
+ E.g. \ x. f (x+x) no point in inlining (+) here!
+
+ (b) It's ineffective. Once g's wrapper is inlined, its case-expressions
+ aren't scrutinising arguments any more
+
+ case alts of
+
+ [alt] -> size_up_alt alt `addSize` SizeIs 0# (unitBag (v, 1)) 0#
+ -- We want to make wrapper-style evaluation look cheap, so that
+ -- when we inline a wrapper it doesn't make call site (much) bigger
+ -- Otherwise we get nasty phase ordering stuff:
+ -- f x = g x x
+ -- h y = ...(f e)...
+ -- If we inline g's wrapper, f looks big, and doesn't get inlined
+ -- into h; if we inline f first, while it looks small, then g's
+ -- wrapper will get inlined later anyway. To avoid this nasty
+ -- ordering difference, we make (case a of (x,y) -> ...),
+ -- *where a is one of the arguments* look free.
+
+ other ->
+-}
+ alts_size (foldr addSize sizeOne alt_sizes) -- The 1 is for the scrutinee
+ (foldr1 maxSize alt_sizes)
+
-- Good to inline if an arg is scrutinised, because
-- that may eliminate allocation in the caller
-- And it eliminates the case itself
- | otherwise
- = size_up_alt alt
-
- -- Scrutinising one of the argument variables,
- -- with more than one alternative
- size_up (Case (Var v) _ alts)
- | v `elem` top_args
- = alts_size (foldr addSize sizeOne alt_sizes) -- The 1 is for the scrutinee
- (foldr1 maxSize alt_sizes)
+
where
- v_in_args = v `elem` top_args
alt_sizes = map size_up_alt alts
+ -- alts_size tries to compute a good discount for
+ -- the case when we are scrutinising an argument variable
alts_size (SizeIs tot tot_disc tot_scrut) -- Size of all alternatives
(SizeIs max max_disc max_scrut) -- Size of biggest alternative
- = SizeIs tot (unitBag (v, I# (1# +# tot -# max)) `unionBags` max_disc) max_scrut
+ = SizeIs tot (unitBag (v, iBox (_ILIT 1 +# tot -# max)) `unionBags` max_disc) max_scrut
-- If the variable is known, we produce a discount that
-- will take us back to 'max', the size of rh largest alternative
-- The 1+ is a little discount for reduced allocation in the caller
-
alts_size tot_size _ = tot_size
-- Also if the function is a constant Id (constr or primop)
-- compute discounts specially
size_up_fun (Var fun) args
- | idUnique fun == buildIdKey = buildSize
- | idUnique fun == augmentIdKey = augmentSize
+ | fun `hasKey` buildIdKey = buildSize
+ | fun `hasKey` augmentIdKey = augmentSize
| otherwise
- = case idFlavour fun of
- DataConId dc -> conSizeN (valArgCount args)
+ = case globalIdDetails fun of
+ DataConWorkId dc -> conSizeN dc (valArgCount args)
+ FCallId fc -> sizeN opt_UF_DearOp
PrimOpId op -> primOpSize op (valArgCount args)
-- foldr addSize (primOpSize op) (map arg_discount args)
-- At one time I tried giving an arg-discount if a primop
------------
size_up_alt (con, bndrs, rhs) = size_up rhs
- -- Don't charge for args, so that wrappers look cheap
+ -- Don't charge for args, so that wrappers look cheap
+ -- (See comments about wrappers with Case)
------------
-- We want to record if we're case'ing, or applying, an argument
fun_discount v | v `elem` top_args = SizeIs 0# (unitBag (v, opt_UF_FunAppDiscount)) 0#
- fun_discount other = sizeZero
+ fun_discount other = sizeZero
------------
-- These addSize things have to be here because
-- I don't want to give them bOMB_OUT_SIZE as an argument
- addSizeN TooBig _ = TooBig
- addSizeN (SizeIs n xs d) (I# m)
- | n_tot ># bOMB_OUT_SIZE = TooBig
- | otherwise = SizeIs n_tot xs d
- where
- n_tot = n +# m
+ addSizeN TooBig _ = TooBig
+ addSizeN (SizeIs n xs d) m = mkSizeIs bOMB_OUT_SIZE (n +# iUnbox m) xs d
- addSize TooBig _ = TooBig
- addSize _ TooBig = TooBig
- addSize (SizeIs n1 xs d1) (SizeIs n2 ys d2)
- | n_tot ># bOMB_OUT_SIZE = TooBig
- | otherwise = SizeIs n_tot xys d_tot
- where
- n_tot = n1 +# n2
- d_tot = d1 +# d2
- xys = xs `unionBags` ys
+ addSize TooBig _ = TooBig
+ addSize _ TooBig = TooBig
+ addSize (SizeIs n1 xs d1) (SizeIs n2 ys d2)
+ = mkSizeIs bOMB_OUT_SIZE (n1 +# n2) (xs `unionBags` ys) (d1 +# d2)
\end{code}
Code for manipulating sizes
\begin{code}
-
data ExprSize = TooBig
- | SizeIs Int# -- Size found
+ | SizeIs FastInt -- Size found
(Bag (Id,Int)) -- Arguments cased herein, and discount for each such
- Int# -- Size to subtract if result is scrutinised
+ FastInt -- Size to subtract if result is scrutinised
-- by a case expression
-isTooBig TooBig = True
-isTooBig _ = False
-
+-- subtract the discount before deciding whether to bale out. eg. we
+-- want to inline a large constructor application into a selector:
+-- tup = (a_1, ..., a_99)
+-- x = case tup of ...
+--
+mkSizeIs max n xs d | (n -# d) ># max = TooBig
+ | otherwise = SizeIs n xs d
+
maxSize TooBig _ = TooBig
maxSize _ TooBig = TooBig
maxSize s1@(SizeIs n1 _ _) s2@(SizeIs n2 _ _) | n1 ># n2 = s1
| otherwise = s2
-sizeZero = SizeIs 0# emptyBag 0#
-sizeOne = SizeIs 1# emptyBag 0#
-sizeTwo = SizeIs 2# emptyBag 0#
-sizeN (I# n) = SizeIs n emptyBag 0#
-conSizeN (I# n) = SizeIs 1# emptyBag (n +# 1#)
+sizeZero = SizeIs (_ILIT 0) emptyBag (_ILIT 0)
+sizeOne = SizeIs (_ILIT 1) emptyBag (_ILIT 0)
+sizeN n = SizeIs (iUnbox n) emptyBag (_ILIT 0)
+conSizeN dc n
+ | isUnboxedTupleCon dc = SizeIs (_ILIT 0) emptyBag (iUnbox n +# _ILIT 1)
+ | otherwise = SizeIs (_ILIT 1) emptyBag (iUnbox n +# _ILIT 1)
-- Treat constructors as size 1; we are keen to expose them
-- (and we charge separately for their args). We can't treat
- -- them as size zero, else we find that (I# x) has size 1,
+ -- them as size zero, else we find that (iBox x) has size 1,
-- which is the same as a lone variable; and hence 'v' will
- -- always be replaced by (I# x), where v is bound to I# x.
+ -- always be replaced by (iBox x), where v is bound to iBox x.
+ --
+ -- However, unboxed tuples count as size zero
+ -- I found occasions where we had
+ -- f x y z = case op# x y z of { s -> (# s, () #) }
+ -- and f wasn't getting inlined
primOpSize op n_args
| not (primOpIsDupable op) = sizeN opt_UF_DearOp
- | not (primOpOutOfLine op) = sizeZero -- These are good to inline
+ | not (primOpOutOfLine op) = sizeN (2 - n_args)
+ -- Be very keen to inline simple primops.
+ -- We give a discount of 1 for each arg so that (op# x y z) costs 2.
+ -- We can't make it cost 1, else we'll inline let v = (op# x y z)
+ -- at every use of v, which is excessive.
+ --
+ -- A good example is:
+ -- let x = +# p q in C {x}
+ -- Even though x get's an occurrence of 'many', its RHS looks cheap,
+ -- and there's a good chance it'll get inlined back into C's RHS. Urgh!
| otherwise = sizeOne
buildSize = SizeIs (-2#) emptyBag 4#
nukeScrutDiscount TooBig = TooBig
-- When we return a lambda, give a discount if it's used (applied)
-lamScrutDiscount (SizeIs n vs d) = case opt_UF_FunAppDiscount of { I# d -> SizeIs n vs d }
+lamScrutDiscount (SizeIs n vs d) = case opt_UF_FunAppDiscount of { d -> SizeIs n vs (iUnbox d) }
lamScrutDiscount TooBig = TooBig
\end{code}
UnfoldNever -> False
other -> True
-certainlyWillInline :: Id -> Bool
- -- Sees if the Id is pretty certain to inline
-certainlyWillInline v
- = case idUnfolding v of
-
- CoreUnfolding _ _ _ is_value _ g@(UnfoldIfGoodArgs n_vals _ size _)
- -> is_value
- && size - (n_vals +1) <= opt_UF_UseThreshold
-
- other -> False
+certainlyWillInline :: Unfolding -> Bool
+ -- Sees if the unfolding is pretty certain to inline
+certainlyWillInline (CoreUnfolding _ _ _ is_cheap (UnfoldIfGoodArgs n_vals _ size _))
+ = is_cheap && size - (n_vals +1) <= opt_UF_UseThreshold
+certainlyWillInline other
+ = False
\end{code}
@okToUnfoldInHifile@ is used when emitting unfolding info into an interface
okToUnfoldInHiFile e = opt_UnfoldCasms || go e
where
-- Race over an expression looking for CCalls..
- go (Var v) = case isPrimOpId_maybe v of
- Just op -> okToUnfoldPrimOp op
- Nothing -> True
+ go (Var v) = case isFCallId_maybe v of
+ Just fcall -> okToExposeFCall fcall
+ Nothing -> True
go (Lit lit) = not (isLitLitLit lit)
go (App fun arg) = go fun && go arg
go (Lam _ body) = go body
go (Let binds body) = and (map go (body :rhssOfBind binds))
- go (Case scrut bndr alts) = and (map go (scrut:rhssOfAlts alts))
+ go (Case scrut bndr alts) = and (map go (scrut:rhssOfAlts alts)) &&
+ not (any isLitLitLit [ lit | (LitAlt lit, _, _) <- alts ])
go (Note _ body) = go body
go (Type _) = True
-
- -- ok to unfold a PrimOp as long as it's not a _casm_
- okToUnfoldPrimOp (CCallOp ccall) = not (ccallIsCasm ccall)
- okToUnfoldPrimOp _ = True
\end{code}
StrictAnal.addStrictnessInfoToTopId
\begin{code}
-callSiteInline :: Bool -- True <=> the Id is black listed
+callSiteInline :: DynFlags
+ -> Bool -- True <=> the Id can be inlined
-> Bool -- 'inline' note at call site
-> OccInfo
-> Id -- The Id
-> Maybe CoreExpr -- Unfolding, if any
-callSiteInline black_listed inline_call occ id arg_infos interesting_cont
+callSiteInline dflags active_inline inline_call occ id arg_infos interesting_cont
= case idUnfolding id of {
NoUnfolding -> Nothing ;
OtherCon cs -> Nothing ;
- CompulsoryUnfolding unf_template | black_listed -> Nothing
- | otherwise -> Just unf_template ;
- -- Constructors have compulsory unfoldings, but
- -- may have rules, in which case they are
- -- black listed till later
- CoreUnfolding unf_template is_top is_cheap is_value is_bot guidance ->
+
+ CompulsoryUnfolding unf_template -> Just unf_template ;
+ -- CompulsoryUnfolding => there is no top-level binding
+ -- for these things, so we must inline it.
+ -- Only a couple of primop-like things have
+ -- compulsory unfoldings (see MkId.lhs).
+ -- We don't allow them to be inactive
+
+ CoreUnfolding unf_template is_top is_value is_cheap guidance ->
let
result | yes_or_no = Just unf_template
n_val_args = length arg_infos
- ok_inside_lam = is_value || is_bot || (is_cheap && not is_top)
- -- I'm experimenting with is_cheap && not is_top
-
yes_or_no
- | black_listed = False
- | otherwise = case occ of
+ | not active_inline = False
+ | otherwise = case occ of
IAmDead -> pprTrace "callSiteInline: dead" (ppr id) False
IAmALoopBreaker -> False
- OneOcc in_lam one_br -> (not in_lam || ok_inside_lam) && consider_safe in_lam True one_br
- NoOccInfo -> ok_inside_lam && consider_safe True False False
+ OneOcc in_lam one_br -> (not in_lam || is_cheap) && consider_safe in_lam True one_br
+ NoOccInfo -> is_cheap && consider_safe True False False
consider_safe in_lam once once_in_one_branch
-- consider_safe decides whether it's a good idea to inline something,
-- then if the context is totally uninteresting (not applied, not scrutinised)
-- there is no point in substituting because it might just increase allocation,
-- by allocating the function itself many times
+ -- Note [Jan 2002]: this comment looks out of date. The actual code
+ -- doesn't inline *ever* in an uninteresting context. Why not? I
+ -- think it's just because we don't want to inline top-level constants
+ -- into uninteresting contexts, lest we (for example) re-nest top-level
+ -- literal lists.
--
-- Note: there used to be a '&& not top_level' in the guard above,
-- but that stopped us inlining top-level functions used only once,
-- which is stupid
- = not in_lam || not (null arg_infos) || interesting_cont
+ = WARN( not is_top && not in_lam, ppr id )
+ -- If (not in_lam) && one_br then PreInlineUnconditionally
+ -- should have caught it, shouldn't it? Unless it's a top
+ -- level thing.
+ notNull arg_infos || interesting_cont
| otherwise
= case guidance of
UnfoldIfGoodArgs n_vals_wanted arg_discounts size res_discount
| enough_args && size <= (n_vals_wanted + 1)
- -- No size increase
+ -- Inline unconditionally if there no size increase
-- Size of call is n_vals_wanted (+1 for the function)
-> True
arg_infos really_interesting_cont
in
-#ifdef DEBUG
- if opt_D_dump_inlinings then
+ if dopt Opt_D_dump_inlinings dflags then
pprTrace "Considering inlining"
- (ppr id <+> vcat [text "black listed" <+> ppr black_listed,
+ (ppr id <+> vcat [text "active:" <+> ppr active_inline,
text "occ info:" <+> ppr occ,
text "arg infos" <+> ppr arg_infos,
text "interesting continuation" <+> ppr interesting_cont,
text "is value:" <+> ppr is_value,
text "is cheap:" <+> ppr is_cheap,
- text "is bottom:" <+> ppr is_bot,
- text "is top-level:" <+> ppr is_top,
text "guidance" <+> ppr guidance,
text "ANSWER =" <+> if yes_or_no then text "YES" else text "NO",
if yes_or_no then
else empty])
result
else
-#endif
result
}
-- Discount of 1 for each arg supplied, because the
-- result replaces the call
round (opt_UF_KeenessFactor *
- fromInt (arg_discount + result_discount))
+ fromIntegral (arg_discount + result_discount))
where
arg_discount = sum (zipWith mk_arg_discount arg_discounts arg_infos)
result_discount | result_used = res_discount -- Over-applied, or case scrut
| otherwise = 0
\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Black-listing}
-%* *
-%************************************************************************
-
-Inlining is controlled by the "Inline phase" number, which is set
-by the per-simplification-pass '-finline-phase' flag.
-
-For optimisation we use phase 1,2 and nothing (i.e. no -finline-phase flag)
-in that order. The meanings of these are determined by the @blackListed@ function
-here.
-
-The final simplification doesn't have a phase number.
-
-Pragmas
-~~~~~~~
- Pragma Black list if
-
-(least black listing, most inlining)
- INLINE n foo phase is Just p *and* p<n *and* foo appears on LHS of rule
- INLINE foo phase is Just p *and* foo appears on LHS of rule
- NOINLINE n foo phase is Just p *and* (p<n *or* foo appears on LHS of rule)
- NOINLINE foo always
-(most black listing, least inlining)
-
-\begin{code}
-blackListed :: IdSet -- Used in transformation rules
- -> Maybe Int -- Inline phase
- -> Id -> Bool -- True <=> blacklisted
-
--- The blackListed function sees whether a variable should *not* be
--- inlined because of the inline phase we are in. This is the sole
--- place that the inline phase number is looked at.
-
-blackListed rule_vars Nothing -- Last phase
- = \v -> isNeverInlinePrag (idInlinePragma v)
-
-blackListed rule_vars (Just phase)
- = \v -> normal_case rule_vars phase v
-
-normal_case rule_vars phase v
- = case idInlinePragma v of
- NoInlinePragInfo -> has_rules
-
- IMustNotBeINLINEd from_INLINE Nothing
- | from_INLINE -> has_rules -- Black list until final phase
- | otherwise -> True -- Always blacklisted
-
- IMustNotBeINLINEd from_inline (Just threshold)
- | from_inline -> (phase < threshold && has_rules)
- | otherwise -> (phase < threshold || has_rules)
- where
- has_rules = v `elemVarSet` rule_vars
- || not (isEmptyCoreRules (idSpecialisation v))
-\end{code}
-
-
-SLPJ 95/04: Why @runST@ must be inlined very late:
-\begin{verbatim}
-f x =
- runST ( \ s -> let
- (a, s') = newArray# 100 [] s
- (_, s'') = fill_in_array_or_something a x s'
- in
- freezeArray# a s'' )
-\end{verbatim}
-If we inline @runST@, we'll get:
-\begin{verbatim}
-f x = let
- (a, s') = newArray# 100 [] realWorld#{-NB-}
- (_, s'') = fill_in_array_or_something a x s'
- in
- freezeArray# a s''
-\end{verbatim}
-And now the @newArray#@ binding can be floated to become a CAF, which
-is totally and utterly wrong:
-\begin{verbatim}
-f = let
- (a, s') = newArray# 100 [] realWorld#{-NB-} -- YIKES!!!
- in
- \ x ->
- let (_, s'') = fill_in_array_or_something a x s' in
- freezeArray# a s''
-\end{verbatim}
-All calls to @f@ will share a {\em single} array!
-
-Yet we do want to inline runST sometime, so we can avoid
-needless code. Solution: black list it until the last moment.
-