certainlyWillInline,
okToUnfoldInHiFile,
- callSiteInline, blackListed
+ callSiteInline
) where
#include "HsVersions.h"
import OccurAnal ( occurAnalyseGlobalExpr )
import CoreUtils ( exprIsValue, exprIsCheap, exprIsTrivial )
import Id ( Id, idType, isId,
- idSpecialisation, idInlinePragma, idUnfolding,
+ idUnfolding,
isFCallId_maybe, globalIdDetails
)
-import VarSet
+import DataCon ( isUnboxedTupleCon )
import Literal ( isLitLitLit, litSize )
import PrimOp ( primOpIsDupable, primOpOutOfLine )
import ForeignCall ( okToExposeFCall )
-import IdInfo ( InlinePragInfo(..), OccInfo(..), GlobalIdDetails(..),
- isNeverInlinePrag
- )
+import IdInfo ( OccInfo(..), GlobalIdDetails(..) )
import Type ( isUnLiftedType )
import PrelNames ( hasKey, buildIdKey, augmentIdKey )
import Bag
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
+
(exprIsValue expr)
-- Already evaluated
-- 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
\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
| fun `hasKey` augmentIdKey = augmentSize
| otherwise
= case globalIdDetails fun of
- DataConId dc -> conSizeN (valArgCount args)
+ DataConWorkId dc -> conSizeN dc (valArgCount args)
FCallId fc -> sizeN opt_UF_DearOp
PrimOpId op -> primOpSize op (valArgCount args)
-- 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) m
- | n_tot ># (iUnbox bOMB_OUT_SIZE) = TooBig
- | otherwise = SizeIs n_tot xs d
- where
- n_tot = n +# iUnbox 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 ># (iUnbox 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 FastInt -- Size found
(Bag (Id,Int)) -- Arguments cased herein, and discount for each such
FastInt -- Size to subtract if result is scrutinised
-- by a case expression
-
+-- 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 (_ILIT 0) emptyBag (_ILIT 0)
-sizeOne = SizeIs (_ILIT 1) emptyBag (_ILIT 0)
+sizeZero = SizeIs (_ILIT 0) emptyBag (_ILIT 0)
+sizeOne = SizeIs (_ILIT 1) emptyBag (_ILIT 0)
sizeN n = SizeIs (iUnbox n) emptyBag (_ILIT 0)
-conSizeN n = SizeIs (_ILIT 1) emptyBag (iUnbox n +# _ILIT 1)
+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 (iBox x) has size 1,
-- which is the same as a lone variable; and hence 'v' will
-- 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) = sizeN (1 - n_args)
+ | 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 1.
- -- I found occasions where we had
- -- f x y z = case op# x y z of { s -> (# s, () #) }
- -- and f wasn't getting inlined
+ -- 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#
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
\begin{code}
callSiteInline :: DynFlags
- -> Bool -- True <=> the Id is black listed
+ -> Bool -- True <=> the Id can be inlined
-> Bool -- 'inline' note at call site
-> OccInfo
-> Id -- The Id
-> Maybe CoreExpr -- Unfolding, if any
-callSiteInline dflags 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
+
+ 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
n_val_args = length arg_infos
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 || is_cheap) && consider_safe in_lam True one_br
-- 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
- = WARN( not in_lam, ppr id ) -- If (not in_lam) && one_br then PreInlineUnconditionally
- -- should have caught it, shouldn't it?
- 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
in
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,
-- 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.
-
projects / ghc-hetmet.git / blobdiff