%
-% (c) The AQUA Project, Glasgow University, 1994-1996
+% (c) The AQUA Project, Glasgow University, 1994-1998
%
\section[CoreUnfold]{Core-syntax unfoldings}
The type @Unfolding@ sits ``above'' simply-Core-expressions
unfoldings, capturing ``higher-level'' things we know about a binding,
usually things that the simplifier found out (e.g., ``it's a
-literal''). In the corner of a @SimpleUnfolding@ unfolding, you will
+literal''). In the corner of a @CoreUnfolding@ unfolding, you will
find, unsurprisingly, a Core expression.
\begin{code}
-#include "HsVersions.h"
-
module CoreUnfold (
- SimpleUnfolding(..), Unfolding(..), UnfoldingGuidance(..), -- types
- UfExpr, RdrName, -- For closure (delete in 1.3)
-
- FormSummary(..), mkFormSummary, whnfOrBottom, exprSmallEnoughToDup,
+ Unfolding(..), UnfoldingGuidance(..), -- types
noUnfolding, mkMagicUnfolding, mkUnfolding, getUnfoldingTemplate,
+ isEvaldUnfolding, hasUnfolding,
- smallEnoughToInline, couldBeSmallEnoughToInline, certainlySmallEnoughToInline,
- okToInline,
+ smallEnoughToInline, couldBeSmallEnoughToInline,
+ certainlySmallEnoughToInline,
+ okToUnfoldInHiFile,
calcUnfoldingGuidance
) where
-IMP_Ubiq()
-IMPORT_DELOOPER(IdLoop) -- for paranoia checking;
- -- and also to get mkMagicUnfoldingFun
-IMPORT_DELOOPER(PrelLoop) -- for paranoia checking
+#include "HsVersions.h"
-import Bag ( emptyBag, unitBag, unionBags, Bag )
+import {-# SOURCE #-} MagicUFs ( MagicUnfoldingFun, mkMagicUnfoldingFun )
import CmdLineOpts ( opt_UnfoldingCreationThreshold,
opt_UnfoldingUseThreshold,
- opt_UnfoldingConDiscount
+ opt_UnfoldingConDiscount,
+ opt_UnfoldingKeenessFactor,
+ opt_UnfoldCasms
)
import Constants ( uNFOLDING_CHEAP_OP_COST,
uNFOLDING_DEAR_OP_COST,
uNFOLDING_NOREP_LIT_COST
)
-import BinderInfo ( BinderInfo(..), FunOrArg, DuplicationDanger, InsideSCC, isDupDanger )
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,
- SYN_IE(IdSet), GenId{-instances-} )
-import PrimOp ( primOpCanTriggerGC, fragilePrimOp, PrimOp(..) )
-import IdInfo ( ArityInfo(..), bottomIsGuaranteed )
-import Literal ( isNoRepLit, isLitLitLit )
-import Pretty
+import CoreUtils ( coreExprType, exprIsTrivial, mkFormSummary,
+ FormSummary(..) )
+import Id ( Id, idType, isId )
+import Const ( Con(..), isLitLitLit )
+import PrimOp ( PrimOp(..), primOpOutOfLine )
+import IdInfo ( ArityInfo(..), InlinePragInfo(..) )
import TyCon ( tyConFamilySize )
-import Type ( maybeAppDataTyConExpandingDicts )
-import UniqSet ( emptyUniqSet, unitUniqSet, mkUniqSet,
- addOneToUniqSet, unionUniqSets
- )
-import Usage ( SYN_IE(UVar) )
-import Util ( isIn, panic, assertPanic )
-
+import Type ( splitAlgTyConApp_maybe )
+import Const ( isNoRepLit )
+import Unique ( Unique )
+import Util ( isIn, panic )
+import Outputable
\end{code}
%************************************************************************
data Unfolding
= NoUnfolding
- | CoreUnfolding SimpleUnfolding
-
- | MagicUnfolding
- Unique -- Unique of the Id whose magic unfolding this is
- MagicUnfoldingFun
-
+ | 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.
-data SimpleUnfolding
- = SimpleUnfolding -- An unfolding with redundant cached information
+ | CoreUnfolding -- An unfolding with redundant cached information
FormSummary -- Tells whether the template is a WHNF or bottom
UnfoldingGuidance -- Tells about the *size* of the template.
- SimplifiableCoreExpr -- Template
+ CoreExpr -- Template; binder-info is correct
+ | MagicUnfolding
+ Unique -- Unique of the Id whose magic unfolding this is
+ MagicUnfoldingFun
+\end{code}
+\begin{code}
noUnfolding = NoUnfolding
-mkUnfolding inline_me expr
- = CoreUnfolding (SimpleUnfolding
- (mkFormSummary expr)
- (calcUnfoldingGuidance inline_me opt_UnfoldingCreationThreshold expr)
- (occurAnalyseGlobalExpr expr))
+mkUnfolding expr
+ = let
+ -- strictness mangling (depends on there being no CSE)
+ ufg = calcUnfoldingGuidance opt_UnfoldingCreationThreshold expr
+ occ = occurAnalyseGlobalExpr expr
+ in
+ CoreUnfolding (mkFormSummary expr) ufg occ
mkMagicUnfolding :: Unique -> Unfolding
mkMagicUnfolding tag = MagicUnfolding tag (mkMagicUnfoldingFun tag)
getUnfoldingTemplate :: Unfolding -> CoreExpr
-getUnfoldingTemplate (CoreUnfolding (SimpleUnfolding _ _ expr))
- = unTagBinders expr
+getUnfoldingTemplate (CoreUnfolding _ _ expr) = expr
getUnfoldingTemplate other = panic "getUnfoldingTemplate"
+isEvaldUnfolding :: Unfolding -> Bool
+isEvaldUnfolding (OtherCon _) = True
+isEvaldUnfolding (CoreUnfolding ValueForm _ expr) = True
+isEvaldUnfolding other = False
+
+hasUnfolding :: Unfolding -> Bool
+hasUnfolding NoUnfolding = False
+hasUnfolding other = True
data UnfoldingGuidance
= UnfoldNever
| 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 = ppStr "_ALWAYS_"
--- ppr sty EssentialUnfolding = ppStr "_ESSENTIAL_" -- shouldn't appear in an iface
- ppr sty (UnfoldIfGoodArgs t v cs size)
- = ppCat [ppStr "_IF_ARGS_", ppInt t, ppInt v,
+ ppr UnfoldAlways = ptext SLIT("_ALWAYS_")
+ ppr (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}
%************************************************************************
%* *
-\subsection{Figuring out things about expressions}
-%* *
-%************************************************************************
-
-\begin{code}
-data FormSummary
- = VarForm -- Expression is a variable (or scc var, etc)
- | ValueForm -- Expression is a value: i.e. a value-lambda,constructor, or literal
- | BottomForm -- Expression is guaranteed to be bottom. We're more gung
- -- ho about inlining such things, because it can't waste work
- | OtherForm -- Anything else
-
-instance Outputable FormSummary where
- ppr sty VarForm = ppStr "Var"
- ppr sty ValueForm = ppStr "Value"
- ppr sty BottomForm = ppStr "Bot"
- ppr sty OtherForm = ppStr "Other"
-
-mkFormSummary ::GenCoreExpr bndr Id tyvar uvar -> FormSummary
-
-mkFormSummary expr
- = go (0::Int) expr -- The "n" is the number of (value) arguments so far
- where
- go n (Lit _) = ASSERT(n==0) ValueForm
- go n (Con _ _) = ASSERT(n==0) ValueForm
- go n (Prim _ _) = OtherForm
- go n (SCC _ e) = go n e
- go n (Coerce _ _ e) = go n e
- go n (Let _ e) = OtherForm
- go n (Case _ _) = OtherForm
-
- go 0 (Lam (ValBinder x) e) = ValueForm -- NB: \x.bottom /= bottom!
- go n (Lam (ValBinder x) e) = go (n-1) e -- Applied lambda
- go n (Lam other_binder e) = go n e
-
- go n (App fun arg) | isValArg arg = go (n+1) fun
- go n (App fun other_arg) = go n fun
-
- go n (Var f) | isBottomingId f = BottomForm
- go 0 (Var f) = VarForm
- go n (Var f) = case getIdArity f of
- ArityExactly a | n < a -> ValueForm
- 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
-\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 expr
- = case (collectArgs expr) of { (fun, _, _, vargs) ->
- case fun of
- Var v | length vargs == 0 -> 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?
-
-%************************************************************************
-%* *
\subsection[calcUnfoldingGuidance]{Calculate ``unfolding guidance'' for an expression}
%* *
%************************************************************************
\begin{code}
calcUnfoldingGuidance
- :: Bool -- True <=> there's an INLINE pragma on this thing
- -> Int -- bomb out if size gets bigger than this
+ :: 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 False bOMB_OUT_SIZE expr
- = let
- (use_binders, ty_binders, val_binders, body) = collectBinders expr
- in
+calcUnfoldingGuidance bOMB_OUT_SIZE expr
+ | exprIsTrivial expr -- Often trivial expressions are never bound
+ -- to an expression, but it can happen. For
+ -- example, the Id for a nullary constructor has
+ -- a trivial expression as its unfolding, and
+ -- we want to make sure that we always unfold it.
+ = UnfoldAlways
+
+ | otherwise
+ = case collectTyAndValBinders expr of { (ty_binders, val_binders, body) ->
case (sizeExpr bOMB_OUT_SIZE val_binders body) of
- Nothing -> UnfoldNever
+ TooBig -> UnfoldNever
- Just (size, cased_args)
- -> let
- uf = UnfoldIfGoodArgs
+ SizeIs size cased_args scrut_discount
+ -> UnfoldIfGoodArgs
(length ty_binders)
(length val_binders)
(map discount_for val_binders)
- size
-
- discount_for b
- | is_data && b `is_elem` cased_args = tyConFamilySize tycon
- | otherwise = 0
+ (I# size)
+ (I# scrut_discount)
+ where
+ discount_for b
+ | num_cases == 0 = 0
+ | otherwise
+ = if is_data
+ then tyConFamilySize tycon * num_cases
+ else num_cases -- prim cases are pretty cheap
+
where
(is_data, tycon)
- = --trace "CoreUnfold.getAppDataTyConExpandingDicts:1" $
- case (maybeAppDataTyConExpandingDicts (idType b)) of
+ = case (splitAlgTyConApp_maybe (idType b)) of
Nothing -> (False, panic "discount")
Just (tc,_,_) -> (True, tc)
- in
- -- pprTrace "calcUnfold:" (ppAbove (ppr PprDebug uf) (ppr PprDebug expr))
- uf
- where
- is_elem = isIn "calcUnfoldingGuidance"
+ num_cases = length (filter (==b) cased_args)
+ }
\end{code}
\begin{code}
-> [Id] -- Arguments; we're interested in which of these
-- get case'd
-> CoreExpr
- -> Maybe (Int, -- Size
- [Id] -- Subset of args which are cased
- )
+ -> ExprSize
-sizeExpr bOMB_OUT_SIZE args expr
+sizeExpr (I# bOMB_OUT_SIZE) args expr
= size_up expr
where
+ size_up (Type t) = sizeZero -- Types cost nothing
+ size_up (Note _ body) = size_up body -- Notes cost nothing
size_up (Var v) = sizeOne
- size_up (App fun arg) = size_up fun `addSize` size_up_arg arg
- size_up (Lit lit) = if isNoRepLit lit
- then sizeN uNFOLDING_NOREP_LIT_COST
- else sizeOne
-
--- I don't understand this hack so I'm removing it! SLPJ Nov 96
--- size_up (SCC _ (Con _ _)) = Nothing -- **** HACK *****
+ size_up (App fun arg) = size_up fun `addSize` size_up arg
- 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) = -- 1 + # of val args
- sizeN (1 + numValArgs args)
- size_up (Prim op args) = sizeN op_cost -- NB: no charge for PrimOp args
- where
- op_cost = if primOpCanTriggerGC op
- then uNFOLDING_DEAR_OP_COST
- -- these *tend* to be more expensive;
- -- number chosen to avoid unfolding (HACK)
- else uNFOLDING_CHEAP_OP_COST
+ size_up (Con con args) = foldr (addSize . size_up)
+ (size_up_con con (valArgCount args))
+ args
- size_up expr@(Lam _ _)
- = let
- (uvars, tyvars, args, body) = collectBinders expr
- in
- size_up body `addSizeN` length args
+ size_up (Lam b e) | isId b = size_up e `addSizeN` 1
+ | otherwise = size_up e
size_up (Let (NonRec binder rhs) body)
- = size_up rhs
- `addSize`
- size_up body
- `addSizeN`
- 1
+ = nukeScrutDiscount (size_up rhs) `addSize`
+ size_up body `addSizeN`
+ 1 -- For the allocation
size_up (Let (Rec pairs) body)
- = foldr addSize sizeZero [size_up rhs | (_,rhs) <- pairs]
- `addSize`
- size_up body
- `addSizeN`
- length pairs
-
- size_up (Case scrut alts)
- = size_up_scrut scrut
- `addSize`
- size_up_alts (coreExprType scrut) alts
- -- We charge for the "case" itself in "size_up_alts"
-
- ------------
- size_up_arg arg = if isValArg arg then sizeOne else sizeZero{-it's free-}
-
- ------------
- size_up_alts scrut_ty (AlgAlts alts deflt)
- = foldr (addSize . size_alg_alt) (size_up_deflt deflt) alts
- `addSizeN` (if is_data then tyConFamilySize tycon else 1{-??-})
- -- NB: we charge N for an alg. "case", where N is
- -- the number of constructors in the thing being eval'd.
- -- (You'll eventually get a "discount" of N if you
- -- think the "case" is likely to go away.)
+ = nukeScrutDiscount rhs_size `addSize`
+ size_up body `addSizeN`
+ length pairs -- For the allocation
where
- size_alg_alt (con,args,rhs) = size_up rhs
+ 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`
+ case (splitAlgTyConApp_maybe (coreExprType scrut)) of
+ Nothing -> 1
+ Just (tc,_,_) -> tyConFamilySize tc
+
+ ------------
+ size_up_alt (con, bndrs, rhs) = size_up rhs
-- Don't charge for args, so that wrappers look cheap
- (is_data,tycon)
- = --trace "CoreUnfold.getAppDataTyConExpandingDicts:2" $
- case (maybeAppDataTyConExpandingDicts scrut_ty) of
- Nothing -> (False, panic "size_up_alts")
- Just (tc,_,_) -> (True, tc)
+ ------------
+ size_up_con (Literal lit) nv | isNoRepLit lit = sizeN uNFOLDING_NOREP_LIT_COST
+ | otherwise = sizeOne
- size_up_alts _ (PrimAlts alts deflt)
- = foldr (addSize . size_prim_alt) (size_up_deflt deflt) alts
- -- *no charge* for a primitive "case"!
+ size_up_con (DataCon dc) n_val_args = conSizeN n_val_args
+
+ size_up_con (PrimOp op) nv = sizeN op_cost
where
- size_prim_alt (lit,rhs) = size_up rhs
-
- ------------
- size_up_deflt NoDefault = sizeZero
- size_up_deflt (BindDefault binder rhs) = size_up rhs
+ op_cost = if primOpOutOfLine op
+ then uNFOLDING_DEAR_OP_COST
+ -- these *tend* to be more expensive;
+ -- number chosen to avoid unfolding (HACK)
+ else uNFOLDING_CHEAP_OP_COST
------------
- -- 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
+
+
+\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 0# [] n -- We don't count 1 for the constructor because we're
+ -- quite keen to get constructors into the open
+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
+smallEnoughToInline :: Id -- The function (trace msg only)
+ -> [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)
- = enough_args n_vals_wanted arg_is_evald_s &&
- discounted_size <= opt_UnfoldingUseThreshold
+smallEnoughToInline _ _ _ UnfoldAlways = True
+smallEnoughToInline _ _ _ UnfoldNever = False
+smallEnoughToInline id arg_is_evald_s result_is_scruted
+ (UnfoldIfGoodArgs m_tys_wanted n_vals_wanted discount_vec size scrut_discount)
+ = if enough_args n_vals_wanted arg_is_evald_s &&
+ size - discount <= opt_UnfoldingUseThreshold
+ then
+ True
+ else
+ False
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.
+
+ -- we also discount 1 for each argument passed, because these will
+ -- reduce with the lambdas in the function (we count 1 for a lambda
+ -- in size_up).
+
+ discount :: Int
+ discount = length (take n_vals_wanted arg_is_evald_s) +
+ 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
- | otherwise = 1
+ | is_evald = no_of_constrs * opt_UnfoldingConDiscount
+ | otherwise = 0
\end{code}
We use this one to avoid exporting inlinings that we ``couldn't possibly
Just the same as smallEnoughToInline, except that it has no actual arguments.
\begin{code}
-couldBeSmallEnoughToInline :: UnfoldingGuidance -> Bool
-couldBeSmallEnoughToInline guidance = smallEnoughToInline (repeat True) guidance
+couldBeSmallEnoughToInline :: Id -> UnfoldingGuidance -> Bool
+couldBeSmallEnoughToInline id guidance = smallEnoughToInline id (repeat True) True guidance
-certainlySmallEnoughToInline :: UnfoldingGuidance -> Bool
-certainlySmallEnoughToInline guidance = smallEnoughToInline (repeat False) guidance
+certainlySmallEnoughToInline :: Id -> UnfoldingGuidance -> Bool
+certainlySmallEnoughToInline id guidance = smallEnoughToInline id (repeat False) False guidance
\end{code}
-Predicates
-~~~~~~~~~~
+@okToUnfoldInHifile@ is used when emitting unfolding info into an interface
+file to determine whether an unfolding candidate really should be unfolded.
+The predicate is needed to prevent @_casm_@s (+ lit-lits) from being emitted
+into interface files.
+
+The reason for inlining expressions containing _casm_s into interface files
+is that these fragments of C are likely to mention functions/#defines that
+will be out-of-scope when inlined into another module. This is not an
+unfixable problem for the user (just need to -#include the approp. header
+file), but turning it off seems to the simplest thing to do.
\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
-
--- Always inline bottoms
-okToInline BottomForm occ_info small_enough
- = True -- Unless one of the type args is unboxed??
- -- This used to be checked for, but I can't
- -- see why so I've left it out.
-
--- A WHNF can be inlined if it occurs once, or is small
-okToInline form occ_info small_enough
- | is_whnf_form form
- = small_enough || one_occ
+okToUnfoldInHiFile :: CoreExpr -> Bool
+okToUnfoldInHiFile e = opt_UnfoldCasms || go e
where
- one_occ = case occ_info of
- OneOcc _ _ _ n_alts _ -> n_alts <= 1
- other -> False
-
- is_whnf_form VarForm = True
- is_whnf_form ValueForm = True
- is_whnf_form 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)
-
-okToInline form any_occ small_enough = False
+ -- 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 (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 (Note _ body) = go body
+ 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
\end{code}
-
projects / ghc-hetmet.git / blobdiff