import VarEnv ( mkInScopeSet )
import Bag
import Util
+import Pair
import FastTypes
import FastString
import Outputable
+import ForeignCall
+
import Data.Maybe
\end{code}
mkCompulsoryUnfolding :: CoreExpr -> Unfolding
mkCompulsoryUnfolding expr -- Used for things that absolutely must be unfolded
= mkCoreUnfolding InlineCompulsory True
- expr 0 -- Arity of unfolding doesn't matter
+ (simpleOptExpr expr) 0 -- Arity of unfolding doesn't matter
(UnfWhen unSaturatedOk boringCxtOk)
mkInlineUnfolding :: Maybe Arity -> CoreExpr -> Unfolding
a function call to account for. Notice also that constructor applications
are very cheap, because exposing them to a caller is so valuable.
+[25/5/11] All sizes are now multiplied by 10, except for primops.
+This makes primops look cheap, and seems to be almost unversally
+beneficial. Done partly as a result of #4978.
Note [Do not inline top-level bottoming functions]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- See Note [INLINE for small functions]
uncondInline arity size
| arity == 0 = size == 0
- | otherwise = size <= arity + 1
+ | otherwise = size <= 10 * (arity + 1)
\end{code}
size_up (Cast e _) = size_up e
size_up (Note _ e) = size_up e
size_up (Type _) = sizeZero -- Types cost nothing
+ size_up (Coercion _) = sizeZero
size_up (Lit lit) = sizeN (litSize lit)
size_up (Var f) = size_up_call f [] -- Make sure we get constructor
-- discounts even on nullary constructors
size_up (App fun (Type _)) = size_up fun
+ size_up (App fun (Coercion _)) = size_up fun
size_up (App fun arg) = size_up arg `addSizeNSD`
size_up_app fun [arg]
- size_up (Lam b e) | isId b = lamScrutDiscount (size_up e `addSizeN` 1)
+ size_up (Lam b e) | isId b = lamScrutDiscount (size_up e `addSizeN` 10)
| otherwise = size_up e
size_up (Let (NonRec binder rhs) body)
= size_up rhs `addSizeNSD`
size_up body `addSizeN`
- (if isUnLiftedType (idType binder) then 0 else 1)
+ (if isUnLiftedType (idType binder) then 0 else 10)
-- For the allocation
-- If the binder has an unlifted type there is no allocation
size_up (Let (Rec pairs) body)
= foldr (addSizeNSD . size_up . snd)
- (size_up body `addSizeN` length pairs) -- (length pairs) for the allocation
+ (size_up body `addSizeN` (10 * length pairs)) -- (length pairs) for the allocation
pairs
size_up (Case (Var v) _ _ alts)
-- the case when we are scrutinising an argument variable
alts_size (SizeIs tot tot_disc tot_scrut) -- Size of all alternatives
(SizeIs max _ _) -- Size of biggest alternative
- = SizeIs tot (unitBag (v, iBox (_ILIT(2) +# tot -# max)) `unionBags` tot_disc) tot_scrut
+ = SizeIs tot (unitBag (v, iBox (_ILIT(20) +# tot -# max)) `unionBags` tot_disc) tot_scrut
-- If the variable is known, we produce a discount that
-- will take us back to 'max', the size of the 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) = size_up e `addSizeNSD`
- foldr (addAltSize . 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.
- --
- -- Moreover, we charge one per alternative.
+ size_up (Case e _ _ alts) = size_up e `addSizeNSD`
+ foldr (addAltSize . size_up_alt) case_size alts
+ where
+ case_size
+ | is_inline_scrut e, not (lengthExceeds alts 1) = sizeN (-10)
+ | otherwise = sizeZero
+ -- Normally we don't charge for the case itself, but
+ -- we charge one per alternative (see size_up_alt,
+ -- below) to account for the cost of the info table
+ -- and comparisons.
+ --
+ -- However, in certain cases (see is_inline_scrut
+ -- below), no code is generated for the case unless
+ -- there are multiple alts. In these cases we
+ -- subtract one, making the first alt free.
+ -- e.g. case x# +# y# of _ -> ... should cost 1
+ -- case touch# x# of _ -> ... should cost 0
+ -- (see #4978)
+ --
+ -- I would like to not have the "not (lengthExceeds alts 1)"
+ -- condition above, but without that some programs got worse
+ -- (spectral/hartel/event and spectral/para). I don't fully
+ -- understand why. (SDM 24/5/11)
+
+ -- unboxed variables, inline primops and unsafe foreign calls
+ -- are all "inline" things:
+ is_inline_scrut (Var v) = isUnLiftedType (idType v)
+ is_inline_scrut scrut
+ | (Var f, _) <- collectArgs scrut
+ = case idDetails f of
+ FCallId fc -> not (isSafeForeignCall fc)
+ PrimOpId op -> not (primOpOutOfLine op)
+ _other -> False
+ | otherwise
+ = False
------------
-- size_up_app is used when there's ONE OR MORE value args
size_up_app (App fun arg) args
- | isTypeArg arg = size_up_app fun args
+ | isTyCoArg arg = size_up_app fun args
| otherwise = size_up arg `addSizeNSD`
size_up_app fun (arg:args)
size_up_app (Var fun) args = size_up_call fun args
size_up_call :: Id -> [CoreExpr] -> ExprSize
size_up_call fun val_args
= case idDetails fun of
- FCallId _ -> sizeN opt_UF_DearOp
+ FCallId _ -> sizeN (10 * (1 + length val_args))
DataConWorkId dc -> conSize dc (length val_args)
PrimOpId op -> primOpSize op (length val_args)
ClassOpId _ -> classOpSize top_args val_args
_ -> funSize top_args fun (length val_args)
------------
- size_up_alt (_con, _bndrs, rhs) = size_up rhs `addSizeN` 1
+ size_up_alt (_con, _bndrs, rhs) = size_up rhs `addSizeN` 10
-- Don't charge for args, so that wrappers look cheap
-- (See comments about wrappers with Case)
--
-- | Finds a nominal size of a string literal.
litSize :: Literal -> Int
-- Used by CoreUnfold.sizeExpr
-litSize (MachStr str) = 1 + ((lengthFS str + 3) `div` 4)
+litSize (MachStr str) = 10 + 10 * ((lengthFS str + 3) `div` 4)
-- If size could be 0 then @f "x"@ might be too small
-- [Sept03: make literal strings a bit bigger to avoid fruitless
-- duplication of little strings]
classOpSize top_args (arg1 : other_args)
= SizeIs (iUnbox size) arg_discount (_ILIT(0))
where
- size = 2 + length other_args
+ size = 20 + (10 * length other_args)
-- If the class op is scrutinising a lambda bound dictionary then
-- give it a discount, to encourage the inlining of this function
-- The actual discount is rather arbitrarily chosen
res_discount | idArity fun > n_val_args = opt_UF_FunAppDiscount
| otherwise = 0
-- If the function is partially applied, show a result discount
-
- size | some_val_args = 1 + n_val_args
+ size | some_val_args = 10 * (1 + n_val_args)
| otherwise = 0
-- The 1+ is for the function itself
-- Add 1 for each non-trivial arg;
conSize :: DataCon -> Int -> ExprSize
conSize dc n_val_args
- | n_val_args == 0 = SizeIs (_ILIT(0)) emptyBag (_ILIT(1)) -- Like variables
-
--- See Note [Constructor size]
- | isUnboxedTupleCon dc = SizeIs (_ILIT(0)) emptyBag (iUnbox n_val_args +# _ILIT(1))
+ | n_val_args == 0 = SizeIs (_ILIT(0)) emptyBag (_ILIT(10)) -- Like variables
-- See Note [Unboxed tuple result discount]
--- | isUnboxedTupleCon dc = SizeIs (_ILIT(0)) emptyBag (_ILIT(0))
+ | isUnboxedTupleCon dc = SizeIs (_ILIT(0)) emptyBag (iUnbox (10 * (1 + n_val_args)))
-- See Note [Constructor size]
- | otherwise = SizeIs (_ILIT(1)) emptyBag (iUnbox n_val_args +# _ILIT(1))
+ | otherwise = SizeIs (_ILIT(10)) emptyBag (iUnbox (10 * (10 + n_val_args)))
+ -- discont was (10 * (1 + n_val_args)), but it turns out that
+ -- adding a bigger constant here is an unambiguous win. We
+ -- REALLY like unfolding constructors that get scrutinised.
+ -- [SDM, 25/5/11]
\end{code}
Note [Constructor size]
\begin{code}
primOpSize :: PrimOp -> Int -> ExprSize
primOpSize op n_val_args
- | not (primOpIsDupable op) = sizeN opt_UF_DearOp
- | not (primOpOutOfLine op) = sizeN 1
- -- 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 = sizeN n_val_args
+ = if primOpOutOfLine op
+ then sizeN (op_size + n_val_args)
+ else sizeN op_size
+ where
+ op_size = primOpCodeSize op
buildSize :: ExprSize
-buildSize = SizeIs (_ILIT(0)) emptyBag (_ILIT(4))
+buildSize = SizeIs (_ILIT(0)) emptyBag (_ILIT(40))
-- We really want to inline applications of build
-- build t (\cn -> e) should cost only the cost of e (because build will be inlined later)
-- Indeed, we should add a result_discount becuause build is
-- The "4" is rather arbitrary.
augmentSize :: ExprSize
-augmentSize = SizeIs (_ILIT(0)) emptyBag (_ILIT(4))
+augmentSize = SizeIs (_ILIT(0)) emptyBag (_ILIT(40))
-- Ditto (augment t (\cn -> e) ys) should cost only the cost of
-- e plus ys. The -2 accounts for the \cn
UnfNever -> False
UnfWhen {} -> True
UnfIfGoodArgs { ug_size = size}
- -> is_cheap && size - (n_vals +1) <= opt_UF_UseThreshold
+ -> is_cheap && size - (10 * (n_vals +1)) <= opt_UF_UseThreshold
certainlyWillInline _
= False
-- *efficiency* to be gained (e.g. beta reductions, case reductions)
-- by inlining.
- = 1 -- Discount of 1 because the result replaces the call
+ = 10 -- Discount of 1 because the result replaces the call
-- so we count 1 for the function itself
- + length (take n_vals_wanted arg_infos)
+ + 10 * length (take n_vals_wanted arg_infos)
-- Discount of (un-scaled) 1 for each arg supplied,
-- because the result replaces the call
arg_discount = sum (zipWith mk_arg_discount arg_discounts arg_infos)
mk_arg_discount _ TrivArg = 0
- mk_arg_discount _ NonTrivArg = 1
+ mk_arg_discount _ NonTrivArg = 10
mk_arg_discount discount ValueArg = discount
res_discount' = case cont_info of
BoringCtxt -> 0
CaseCtxt -> res_discount
- _other -> 4 `min` res_discount
+ _other -> 40 `min` res_discount
-- res_discount can be very large when a function returns
-- constructors; but we only want to invoke that large discount
-- when there's a case continuation.
conlike_unfolding = isConLikeUnfolding (idUnfolding v)
go (Type _) _ = TrivArg
- go (App fn (Type _)) n = go fn n
+ go (Coercion _) _ = TrivArg
+ go (App fn (Type _)) n = go fn n
+ go (App fn (Coercion _)) n = go fn n
go (App fn _) n = go fn (n+1)
go (Note _ a) n = go a n
go (Cast e _) n = go e n
go (Lam v e) n
- | isTyCoVar v = go e n
+ | isTyVar v = go e n
| n>0 = go e (n-1)
| otherwise = ValueArg
go (Let _ e) n = case go e n of { ValueArg -> ValueArg; _ -> NonTrivArg }
Nothing -> Nothing ;
Just (dc, _dc_univ_args, dc_args) ->
- let (_from_ty, to_ty) = coercionKind co
+ let Pair _from_ty to_ty = coercionKind co
dc_tc = dataConTyCon dc
in
case splitTyConApp_maybe to_ty of {
dc_ex_tyvars = dataConExTyVars dc
arg_tys = dataConRepArgTys dc
- dc_eqs :: [(Type,Type)] -- All equalities from the DataCon
- dc_eqs = [(mkTyVarTy tv, ty) | (tv,ty) <- dataConEqSpec dc] ++
- [getEqPredTys eq_pred | eq_pred <- dataConEqTheta dc]
-
- (ex_args, rest1) = splitAtList dc_ex_tyvars dc_args
- (co_args, val_args) = splitAtList dc_eqs rest1
+ (ex_args, val_args) = splitAtList dc_ex_tyvars dc_args
-- Make the "theta" from Fig 3 of the paper
gammas = decomposeCo tc_arity co
- theta = zipOpenTvSubst (dc_univ_tyvars ++ dc_ex_tyvars)
- (gammas ++ stripTypeArgs ex_args)
-
- -- Cast the existential coercion arguments
- cast_co (ty1, ty2) (Type co)
- = Type $ mkSymCoercion (substTy theta ty1)
- `mkTransCoercion` co
- `mkTransCoercion` (substTy theta ty2)
- cast_co _ other_arg = pprPanic "cast_co" (ppr other_arg)
- new_co_args = zipWith cast_co dc_eqs co_args
-
+ theta = zipOpenCvSubst (dc_univ_tyvars ++ dc_ex_tyvars)
+ (gammas ++ map mkReflCo (stripTypeArgs ex_args))
+
-- Cast the value arguments (which include dictionaries)
new_val_args = zipWith cast_arg arg_tys val_args
- cast_arg arg_ty arg = mkCoerce (substTy theta arg_ty) arg
+ cast_arg arg_ty arg = mkCoerce (liftCoSubst theta arg_ty) arg
in
#ifdef DEBUG
let dump_doc = vcat [ppr dc, ppr dc_univ_tyvars, ppr dc_ex_tyvars,
ppr arg_tys, ppr dc_args, ppr _dc_univ_args,
ppr ex_args, ppr val_args]
in
- ASSERT2( coreEqType _from_ty (mkTyConApp dc_tc _dc_univ_args), dump_doc )
- ASSERT2( all isTypeArg (ex_args ++ co_args), dump_doc )
+ ASSERT2( eqType _from_ty (mkTyConApp dc_tc _dc_univ_args), dump_doc )
+ ASSERT2( all isTypeArg ex_args, dump_doc )
ASSERT2( equalLength val_args arg_tys, dump_doc )
#endif
- Just (dc, to_tc_arg_tys, ex_args ++ new_co_args ++ new_val_args)
+ Just (dc, to_tc_arg_tys, ex_args ++ new_val_args)
}}
exprIsConApp_maybe id_unf expr
-----------
beta (Lam v body) pairs (arg : args)
- | isTypeArg arg
+ | isTyCoArg arg
= beta body ((v,arg):pairs) args
beta (Lam {}) _ _ -- Un-saturated, or not a type lambda
subst = mkOpenSubst (mkInScopeSet (exprFreeVars fun)) pairs
-- doc = vcat [ppr fun, ppr expr, ppr pairs, ppr args]
-
stripTypeArgs :: [CoreExpr] -> [Type]
stripTypeArgs args = ASSERT2( all isTypeArg args, ppr args )
[ty | Type ty <- args]
+ -- We really do want isTypeArg here, not isTyCoArg!
\end{code}
Note [Unfolding DFuns]
projects / ghc-hetmet.git / blobdiff