\begin{code}
module CoreUnfold (
- Unfolding, UnfoldingGuidance, -- types
+ Unfolding, UnfoldingGuidance, -- Abstract types
noUnfolding, mkTopUnfolding, mkUnfolding, mkCompulsoryUnfolding, seqUnfolding,
mkOtherCon, otherCons,
unfoldingTemplate, maybeUnfoldingTemplate,
- isEvaldUnfolding, isCheapUnfolding, isCompulsoryUnfolding,
+ isEvaldUnfolding, isValueUnfolding, isCheapUnfolding, isCompulsoryUnfolding,
hasUnfolding, hasSomeUnfolding,
couldBeSmallEnoughToInline,
- certainlySmallEnoughToInline,
+ certainlyWillInline,
okToUnfoldInHiFile,
- calcUnfoldingGuidance,
-
callSiteInline, blackListed
) where
opt_UF_FunAppDiscount,
opt_UF_PrimArgDiscount,
opt_UF_KeenessFactor,
- opt_UF_CheapOp, opt_UF_DearOp, opt_UF_NoRepLit,
+ opt_UF_CheapOp, opt_UF_DearOp,
opt_UnfoldCasms, opt_PprStyle_Debug,
opt_D_dump_inlinings
)
import PprCore ( pprCoreExpr )
import OccurAnal ( occurAnalyseGlobalExpr )
import BinderInfo ( )
-import CoreUtils ( coreExprType, exprIsTrivial, exprIsValue, exprIsCheap )
-import Id ( Id, idType, idUnique, isId, getIdWorkerInfo,
- getIdSpecialisation, getInlinePragma, getIdUnfolding,
- isConstantId_maybe
+import CoreUtils ( exprIsValue, exprIsCheap, exprIsBottom, exprIsTrivial )
+import Id ( Id, idType, idFlavour, idUnique, isId, idWorkerInfo,
+ idSpecialisation, idInlinePragma, idUnfolding,
+ isPrimOpId_maybe
)
import VarSet
import Name ( isLocallyDefined )
-import Const ( Con(..), isLitLitLit, isWHNFCon )
-import PrimOp ( PrimOp(..), primOpIsDupable )
-import IdInfo ( ArityInfo(..), InlinePragInfo(..), OccInfo(..), insideLam, workerExists )
+import Literal ( isLitLitLit )
+import PrimOp ( PrimOp(..), primOpIsDupable, primOpOutOfLine, ccallIsCasm )
+import IdInfo ( ArityInfo(..), InlinePragInfo(..), OccInfo(..), IdFlavour(..), CprInfo(..), insideLam, workerExists )
import TyCon ( tyConFamilySize )
import Type ( splitAlgTyConApp_maybe, splitFunTy_maybe, isUnLiftedType )
-import Const ( isNoRepLit )
import Unique ( Unique, buildIdKey, augmentIdKey )
import Maybes ( maybeToBool )
import Bag
+import List ( maximumBy )
import Util ( isIn, lengthExceeds )
import Outputable
#endif
\end{code}
+
%************************************************************************
%* *
-\subsection{@Unfolding@ and @UnfoldingGuidance@ types}
+\subsection{Making unfoldings}
%* *
%************************************************************************
\begin{code}
-data Unfolding
- = NoUnfolding
-
- | OtherCon [Con] -- It ain't one of these
- -- (OtherCon xs) also indicates that something has been evaluated
- -- and hence there's no point in re-evaluating it.
- -- OtherCon [] is used even for non-data-type values
- -- to indicated evaluated-ness. Notably:
- -- data C = C !(Int -> Int)
- -- case x of { C f -> ... }
- -- Here, f gets an OtherCon [] unfolding.
-
- | CompulsoryUnfolding CoreExpr -- There is no "original" definition,
- -- so you'd better unfold.
-
- | CoreUnfolding -- An unfolding with redundant cached information
- CoreExpr -- Template; binder-info is correct
- Bool -- This is a top-level binding
- Bool -- exprIsCheap template (cached); it won't duplicate (much) work
- -- if you inline this in more than one place
- Bool -- exprIsValue template (cached); it is ok to discard a `seq` on
- -- this variable
- UnfoldingGuidance -- Tells about the *size* of the template.
-
-seqUnfolding :: Unfolding -> ()
-seqUnfolding (CoreUnfolding e top b1 b2 g)
- = seqExpr e `seq` top `seq` b1 `seq` b2 `seq` seqGuidance g
-seqUnfolding other = ()
-\end{code}
-
-\begin{code}
-noUnfolding = NoUnfolding
-mkOtherCon = OtherCon
-
-mkTopUnfolding expr = mkUnfolding True expr
+mkTopUnfolding expr = mkUnfolding True {- Top level -} expr
mkUnfolding top_lvl expr
= CoreUnfolding (occurAnalyseGlobalExpr expr)
top_lvl
(exprIsCheap expr)
(exprIsValue expr)
+ (exprIsBottom expr)
(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
+ -- two copies of the thing while the occurrence-analysed expression doesn't
+ -- Nevertheless, we don't occ-analyse before computing the size because the
+ -- size computation bales out after a while, whereas occurrence analysis does not.
+ --
+ -- This can occasionally mean that the guidance is very pessimistic;
+ -- it gets fixed up next round
mkCompulsoryUnfolding expr -- Used for things that absolutely must be unfolded
= CompulsoryUnfolding (occurAnalyseGlobalExpr expr)
+\end{code}
-unfoldingTemplate :: Unfolding -> CoreExpr
-unfoldingTemplate (CoreUnfolding expr _ _ _ _) = expr
-unfoldingTemplate (CompulsoryUnfolding expr) = expr
-unfoldingTemplate other = panic "getUnfoldingTemplate"
-
-maybeUnfoldingTemplate :: Unfolding -> Maybe CoreExpr
-maybeUnfoldingTemplate (CoreUnfolding expr _ _ _ _) = Just expr
-maybeUnfoldingTemplate (CompulsoryUnfolding expr) = Just expr
-maybeUnfoldingTemplate other = Nothing
-
-otherCons (OtherCon cons) = cons
-otherCons other = []
-
-isEvaldUnfolding :: Unfolding -> Bool
-isEvaldUnfolding (OtherCon _) = True
-isEvaldUnfolding (CoreUnfolding _ _ _ is_evald _) = is_evald
-isEvaldUnfolding other = False
-
-isCheapUnfolding :: Unfolding -> Bool
-isCheapUnfolding (CoreUnfolding _ _ is_cheap _ _) = is_cheap
-isCheapUnfolding other = False
-
-isCompulsoryUnfolding :: Unfolding -> Bool
-isCompulsoryUnfolding (CompulsoryUnfolding _) = True
-isCompulsoryUnfolding other = False
-
-hasUnfolding :: Unfolding -> Bool
-hasUnfolding (CoreUnfolding _ _ _ _ _) = True
-hasUnfolding (CompulsoryUnfolding _) = True
-hasUnfolding other = False
-
-hasSomeUnfolding :: Unfolding -> Bool
-hasSomeUnfolding NoUnfolding = False
-hasSomeUnfolding other = True
-
-data UnfoldingGuidance
- = UnfoldNever
- | UnfoldIfGoodArgs 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.)
-seqGuidance (UnfoldIfGoodArgs n ns a b) = n `seq` sum ns `seq` a `seq` b `seq` ()
-seqGuidance other = ()
-\end{code}
+%************************************************************************
+%* *
+\subsection{The UnfoldingGuidance type}
+%* *
+%************************************************************************
\begin{code}
instance Outputable UnfoldingGuidance where
\end{code}
-%************************************************************************
-%* *
-\subsection[calcUnfoldingGuidance]{Calculate ``unfolding guidance'' for an expression}
-%* *
-%************************************************************************
-
\begin{code}
calcUnfoldingGuidance
:: Int -- bomb out if size gets bigger than this
= case collect_val_bndrs expr of { (inline, val_binders, body) ->
let
n_val_binders = length val_binders
+
+ max_inline_size = n_val_binders+2
+ -- The idea is that if there is an INLINE pragma (inline is True)
+ -- and there's a big body, we give a size of n_val_binders+2. This
+ -- This is just enough to fail the no-size-increase test in callSiteInline,
+ -- so that INLINE things don't get inlined into entirely boring contexts,
+ -- but no more.
+
in
case (sizeExpr bOMB_OUT_SIZE val_binders body) of
-- have an UnfoldIfGoodArgs guidance
| inline -> UnfoldIfGoodArgs n_val_binders
(map (const 0) val_binders)
- (n_val_binders + 2) 0
- -- See comments with final_size below
+ max_inline_size 0
SizeIs size cased_args scrut_discount
-> UnfoldIfGoodArgs
where
boxed_size = I# size
- final_size | inline = 0 -- Trying very agresssive inlining of INLINE things.
- -- Reason: we don't want to call the un-inlined version,
- -- because its body is awful
- -- boxed_size `min` (n_val_binders + 2) -- Trying "+2" again...
+ final_size | inline = boxed_size `min` max_inline_size
| otherwise = boxed_size
- -- The idea is that if there is an INLINE pragma (inline is True)
- -- and there's a big body, we give a size of n_val_binders+1. This
- -- This is enough to pass the no-size-increase test in callSiteInline,
- -- but no more.
- -- I tried n_val_binders+2, to just defeat the test, on the grounds that
- -- we don't want to inline an INLINE thing into a totally boring context,
- -- but I found that some wrappers (notably one for a join point) weren't
- -- getting inlined, and that was terrible. In that particular case, the
- -- call site applied the wrapper to realWorld#, so if we made that an
- -- "interesting" value the inlining would have happened... but it was
- -- simpler to inline wrappers a little more eagerly instead.
- --
- -- Sometimes, though, an INLINE thing is smaller than n_val_binders+2.
+
+ -- Sometimes an INLINE thing is smaller than n_val_binders+2.
-- A particular case in point is a constructor, which has size 1.
-- We want to inline this regardless, hence the `min`
- discount_for b
- | num_cases == 0 = 0
- | is_fun_ty = num_cases * opt_UF_FunAppDiscount
- | is_data_ty = num_cases * opt_UF_ScrutConDiscount
- | otherwise = num_cases * opt_UF_PrimArgDiscount
- where
- num_cases = foldlBag (\n b' -> if b==b' then n+1 else n) 0 cased_args
- -- Count occurrences of b in cased_args
- arg_ty = idType b
- is_fun_ty = maybeToBool (splitFunTy_maybe arg_ty)
- (is_data_ty, tycon) = case (splitAlgTyConApp_maybe (idType b)) of
- Nothing -> (False, panic "discount")
- Just (tc,_,_) -> (True, tc)
+ discount_for b = foldlBag (\acc (b',n) -> if b==b' then acc+n else acc)
+ 0 cased_args
}
where
-
collect_val_bndrs e = go False [] e
-- We need to be a bit careful about how we collect the
-- value binders. In ptic, if we see
size_up (Note _ body) = size_up body -- Notes cost nothing
size_up (App fun (Type t)) = size_up fun
- size_up (App fun arg) = size_up_app fun [arg]
+ size_up (App fun arg) = size_up_app fun [arg]
- size_up (Con con args) = foldr (addSize . nukeScrutDiscount . size_up)
- (size_up_con con args)
- args
+ size_up (Lit lit) = sizeOne
- size_up (Lam b e) | isId b = size_up e `addSizeN` 1
+ size_up (Lam b e) | isId b = lamScrutDiscount (size_up e `addSizeN` 1)
| otherwise = size_up e
size_up (Let (NonRec binder rhs) body)
where
rhs_size = foldr (addSize . size_up . snd) sizeZero pairs
- size_up (Case scrut _ alts)
- = nukeScrutDiscount (size_up scrut) `addSize`
- arg_discount scrut `addSize`
- foldr (addSize . size_up_alt) sizeZero alts
- `addSizeN` 1 -- charge one for the case itself.
-
--- Just charge for the alts that exist, not the ones that might exist
--- `addSizeN`
--- case (splitAlgTyConApp_maybe (coreExprType scrut)) of
--- Nothing -> 1
--- Just (tc,_,_) -> tyConFamilySize tc
+ -- 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#
+ -- 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 (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
+ -- 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
+
+
+ size_up (Case e _ alts) = nukeScrutDiscount (size_up e) `addSize`
+ foldr (addSize . size_up_alt) sizeZero alts
+ -- We don't charge for the case itself
+ -- It's a strict thing, and the price of the call
+ -- is paid by scrut. Also consider
+ -- case f x of DEFAULT -> e
+ -- This is just ';'! Don't charge for it.
------------
- size_up_app (App fun arg) args = size_up_app fun (arg:args)
+ size_up_app (App fun arg) args
+ | isTypeArg arg = size_up_app fun args
+ | otherwise = size_up_app fun (arg:args)
size_up_app fun args = foldr (addSize . nukeScrutDiscount . size_up)
(size_up_fun fun args)
args
-- A function application with at least one value argument
-- so if the function is an argument give it an arg-discount
+ --
-- Also behave specially if the function is a build
+ --
-- Also if the function is a constant Id (constr or primop)
- -- compute discounts as if it were actually a Con; in the early
- -- stages these constructors and primops may not yet be inlined
- size_up_fun (Var fun) args | idUnique fun == buildIdKey = buildSize
- | idUnique fun == augmentIdKey = augmentSize
- | fun `is_elem` top_args = scrutArg fun `addSize` fun_size
- | otherwise = fun_size
- where
- fun_size = case isConstantId_maybe fun of
- Just con -> size_up_con con args
- Nothing -> sizeOne
+ -- compute discounts specially
+ size_up_fun (Var fun) args
+ | idUnique fun == buildIdKey = buildSize
+ | idUnique fun == augmentIdKey = augmentSize
+ | otherwise
+ = case idFlavour fun of
+ DataConId dc -> conSizeN (valArgCount args)
+
+ 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
+ -- is applied to one of the function's arguments, but it's
+ -- not good. At the moment, any unlifted-type arg gets a
+ -- 'True' for 'yes I'm evald', so we collect the discount even
+ -- if we know nothing about it. And just having it in a primop
+ -- doesn't help at all if we don't know something more.
+
+ other -> fun_discount fun `addSizeN`
+ (1 + length (filter (not . exprIsTrivial) args))
+ -- The 1+ is for the function itself
+ -- Add 1 for each non-trivial arg;
+ -- the allocation cost, as in let(rec)
+ -- Slight hack here: for constructors the args are almost always
+ -- trivial; and for primops they are almost always prim typed
+ -- We should really only count for non-prim-typed args in the
+ -- general case, but that seems too much like hard work
size_up_fun other args = size_up other
-- Don't charge for args, so that wrappers look cheap
------------
- size_up_con (Literal lit) args | isNoRepLit lit = sizeN opt_UF_NoRepLit
- | otherwise = sizeOne
-
- size_up_con (DataCon dc) args = conSizeN (valArgCount args)
-
- size_up_con (PrimOp op) args = foldr addSize (sizeN op_cost) (map arg_discount args)
- -- Give an arg-discount if a primop is applies to
- -- one of the function's arguments
- where
- op_cost | primOpIsDupable op = opt_UF_CheapOp
- | otherwise = opt_UF_DearOp
-
-- We want to record if we're case'ing, or applying, an argument
- arg_discount (Var v) | v `is_elem` top_args = scrutArg v
- arg_discount other = sizeZero
-
- ------------
- is_elem :: Id -> [Id] -> Bool
- is_elem = isIn "size_up_scrut"
+ fun_discount v | v `elem` top_args = SizeIs 0# (unitBag (v, opt_UF_FunAppDiscount)) 0#
+ 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 TooBig _ = TooBig
addSizeN (SizeIs n xs d) (I# m)
- | n_tot -# d <# bOMB_OUT_SIZE = SizeIs n_tot xs d
- | otherwise = TooBig
+ | n_tot ># bOMB_OUT_SIZE = TooBig
+ | otherwise = SizeIs n_tot xs d
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
+ | n_tot ># bOMB_OUT_SIZE = TooBig
+ | otherwise = SizeIs n_tot xys d_tot
where
n_tot = n1 +# n2
d_tot = d1 +# d2
\begin{code}
data ExprSize = TooBig
- | SizeIs Int# -- Size found
- (Bag Id) -- Arguments cased herein
- Int# -- Size to subtract if result is scrutinised
- -- by a case expression
+ | SizeIs Int# -- Size found
+ (Bag (Id,Int)) -- Arguments cased herein, and discount for each such
+ Int# -- Size to subtract if result is scrutinised
+ -- by a case expression
+
+isTooBig TooBig = True
+isTooBig _ = False
+
+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#)
- -- Treat constructors as size 1, that unfoldAlways responsds 'False'
- -- when asked about 'x' when x is bound to (C 3#).
- -- This avoids gratuitous 'ticks' when x itself appears as an
- -- atomic constructor argument.
+ -- 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,
+ -- 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.
+
+primOpSize op n_args
+ | not (primOpIsDupable op) = sizeN opt_UF_DearOp
+ | not (primOpOutOfLine op) = sizeZero -- These are good to inline
+ | otherwise = sizeOne
buildSize = SizeIs (-2#) emptyBag 4#
-- We really want to inline applications of build
-- Ditto (augment t (\cn -> e) ys) should cost only the cost of
-- e plus ys. The -2 accounts for the \cn
-scrutArg v = SizeIs 0# (unitBag v) 0#
-
nukeScrutDiscount (SizeIs n vs d) = SizeIs n vs 0#
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 TooBig = TooBig
\end{code}
Just the same as smallEnoughToInline, except that it has no actual arguments.
\begin{code}
-couldBeSmallEnoughToInline :: UnfoldingGuidance -> Bool
-couldBeSmallEnoughToInline UnfoldNever = False
-couldBeSmallEnoughToInline other = True
-
-certainlySmallEnoughToInline :: UnfoldingGuidance -> Bool
-certainlySmallEnoughToInline UnfoldNever = False
-certainlySmallEnoughToInline (UnfoldIfGoodArgs _ _ size _) = size <= opt_UF_UseThreshold
+couldBeSmallEnoughToInline :: Int -> CoreExpr -> Bool
+couldBeSmallEnoughToInline threshold rhs = case calcUnfoldingGuidance threshold rhs of
+ 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 _ (UnfoldIfGoodArgs n_vals _ size _)
+ -> is_value
+ && size - (n_vals +1) <= opt_UF_UseThreshold
+ && not never_inline
+
+ other -> False
+ where
+ never_inline = case idInlinePragma v of
+ IMustNotBeINLINEd False Nothing -> True
+ 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 _) = True
- go (Con (Literal lit) _) = not (isLitLitLit lit)
- go (Con (PrimOp op) args) = okToUnfoldPrimOp op && all go args
- go (Con con args) = True -- con args are always atomic
+ go (Var v) = case isPrimOpId_maybe v of
+ Just op -> okToUnfoldPrimOp op
+ 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 (Type _) = True
-- ok to unfold a PrimOp as long as it's not a _casm_
- okToUnfoldPrimOp (CCallOp _ is_casm _ _) = not is_casm
- okToUnfoldPrimOp _ = True
+ okToUnfoldPrimOp (CCallOp ccall) = not (ccallIsCasm ccall)
+ okToUnfoldPrimOp _ = True
\end{code}
If the thing is in WHNF, there's no danger of duplicating work,
so we can inline if it occurs once, or is small
+NOTE: we don't want to inline top-level functions that always diverge.
+It just makes the code bigger. Tt turns out that the convenient way to prevent
+them inlining is to give them a NOINLINE pragma, which we do in
+StrictAnal.addStrictnessInfoToTopId
+
\begin{code}
callSiteInline :: Bool -- True <=> the Id is black listed
-> Bool -- 'inline' note at call site
callSiteInline black_listed inline_call occ id arg_infos interesting_cont
- = case getIdUnfolding id of {
+ = case idUnfolding id of {
NoUnfolding -> Nothing ;
OtherCon _ -> Nothing ;
CompulsoryUnfolding unf_template | black_listed -> Nothing
| otherwise -> Just unf_template ;
- -- Primops have compulsory unfoldings, but
+ -- Constructors have compulsory unfoldings, but
-- may have rules, in which case they are
-- black listed till later
- CoreUnfolding unf_template is_top is_cheap _ guidance ->
+ CoreUnfolding unf_template is_top is_cheap is_value is_bot 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
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
- NoOccInfo -> is_cheap && consider_safe True False 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
consider_safe in_lam once once_in_one_branch
-- consider_safe decides whether it's a good idea to inline something,
-- once_in_one_branch = True means there's a unique textual occurrence
| inline_call = True
- | once_in_one_branch -- Be very keen to inline something if this is its unique occurrence; that
- -- gives a good chance of eliminating the original binding for the thing.
- -- The only time we hold back is when substituting inside a lambda;
- -- then if the context is totally uninteresting (not applied, not scrutinised)
- -- there is no point in substituting because it might just increase allocation.
+ | once_in_one_branch
+ -- Be very keen to inline something if this is its unique occurrence:
+ --
+ -- a) Inlining gives a good chance of eliminating the original
+ -- binding (and hence the allocation) for the thing.
+ -- (Provided it's not a top level binding, in which case the
+ -- allocation costs nothing.)
+ --
+ -- b) Inlining a function that is called only once exposes the
+ -- body function to the call site.
+ --
+ -- The only time we hold back is when substituting inside a lambda;
+ -- 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: 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
| otherwise
where
some_benefit = or arg_infos || really_interesting_cont ||
- (not is_top && (once || (n_vals_wanted > 0 && enough_args)))
+ (not is_top && (once || (n_vals_wanted > 0 && enough_args)))
-- If it occurs more than once, there must be something interesting
-- about some argument, or the result context, to make it worth inlining
--
really_interesting_cont | n_val_args < n_vals_wanted = False -- Too few args
| n_val_args == n_vals_wanted = interesting_cont
| otherwise = True -- Extra args
- -- really_interesting_cont tells if the result of the
- -- call is in an interesting context.
-
+ -- really_interesting_cont tells if the result of the
+ -- call is in an interesting context.
+
small_enough = (size - discount) <= opt_UF_UseThreshold
discount = computeDiscount n_vals_wanted arg_discounts res_discount
arg_infos really_interesting_cont
text "occ info:" <+> ppr occ,
text "arg infos" <+> ppr arg_infos,
text "interesting continuation" <+> ppr interesting_cont,
- text "is cheap" <+> ppr is_cheap,
+ 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
-- place that the inline phase number is looked at.
blackListed rule_vars Nothing -- Last phase
- = \v -> case getInlinePragma v of
+ = \v -> case idInlinePragma v of
IMustNotBeINLINEd False Nothing -> True -- An unconditional NOINLINE pragma
other -> False
-blackListed rule_vars (Just 0)
--- Phase 0: used for 'no imported inlinings please'
--- This prevents wrappers getting inlined which in turn is bad for full laziness
--- NEW: try using 'not a wrapper' rather than 'not imported' in this phase.
--- This allows a little more inlining, which seems to be important, sometimes.
--- For example PrelArr.newIntArr gets better.
- = \v -> -- workerExists (getIdWorkerInfo v) || normal_case rule_vars 0 v
- -- True -- Try going back to no inlinings at all
- -- BUT: I found that there is some advantage in doing
- -- local inlinings first. For example in fish/Main.hs
- -- it's advantageous to inline scale_vec2 before inlining
- -- wrappers from PrelNum that make it look big.
- not (isLocallyDefined v) || normal_case rule_vars 0 v -- This seems best at the moment
-
blackListed rule_vars (Just phase)
= \v -> normal_case rule_vars phase v
normal_case rule_vars phase v
- = case getInlinePragma v of
+ = case idInlinePragma v of
NoInlinePragInfo -> has_rules
IMustNotBeINLINEd from_INLINE Nothing
| otherwise -> phase < threshold || has_rules
where
has_rules = v `elemVarSet` rule_vars
- || not (isEmptyCoreRules (getIdSpecialisation v))
+ || not (isEmptyCoreRules (idSpecialisation v))
\end{code}
projects / ghc-hetmet.git / blobdiff