import OccurAnal
import CoreSubst hiding( substTy )
import CoreFVs ( exprFreeVars )
+import CoreArity ( manifestArity )
import CoreUtils
import Id
import DataCon
%************************************************************************
\begin{code}
-mkTopUnfolding :: CoreExpr -> Unfolding
-mkTopUnfolding expr = mkUnfolding True {- Top level -} expr
+mkTopUnfolding :: Bool -> CoreExpr -> Unfolding
+mkTopUnfolding is_bottoming expr
+ = mkUnfolding True {- Top level -} is_bottoming expr
mkImplicitUnfolding :: CoreExpr -> Unfolding
-- For implicit Ids, do a tiny bit of optimising first
-mkImplicitUnfolding expr = mkTopUnfolding (simpleOptExpr expr)
+mkImplicitUnfolding expr = mkTopUnfolding False (simpleOptExpr expr)
-- Note [Top-level flag on inline rules]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- top-level flag to True. It gets set more accurately by the simplifier
-- Simplify.simplUnfolding.
-mkUnfolding :: Bool -> CoreExpr -> Unfolding
-mkUnfolding top_lvl expr
- = mkCoreUnfolding top_lvl expr arity guidance
+mkUnfolding :: Bool -> Bool -> CoreExpr -> Unfolding
+mkUnfolding top_lvl is_bottoming expr
+ = CoreUnfolding { uf_tmpl = occurAnalyseExpr expr,
+ uf_src = InlineRhs,
+ uf_arity = arity,
+ uf_is_top = top_lvl,
+ uf_is_value = exprIsHNF expr,
+ uf_is_conlike = exprIsConLike expr,
+ uf_expandable = exprIsExpandable expr,
+ uf_is_cheap = is_cheap,
+ uf_guidance = guidance }
where
- (arity, guidance) = calcUnfoldingGuidance opt_UF_CreationThreshold expr
+ is_cheap = exprIsCheap expr
+ (arity, guidance) = calcUnfoldingGuidance is_cheap (top_lvl && is_bottoming)
+ 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
-- it gets fixed up next round. And it should be rare, because large
-- let-bound things that are dead are usually caught by preInlineUnconditionally
-mkCoreUnfolding :: Bool -> CoreExpr -> Arity -> UnfoldingGuidance -> Unfolding
+mkCoreUnfolding :: Bool -> UnfoldingSource -> CoreExpr
+ -> Arity -> UnfoldingGuidance -> Unfolding
-- Occurrence-analyses the expression before capturing it
-mkCoreUnfolding top_lvl expr arity guidance
+mkCoreUnfolding top_lvl src expr arity guidance
= CoreUnfolding { uf_tmpl = occurAnalyseExpr expr,
+ uf_src = src,
uf_arity = arity,
uf_is_top = top_lvl,
uf_is_value = exprIsHNF expr,
mkWwInlineRule :: Id -> CoreExpr -> Arity -> Unfolding
mkWwInlineRule id expr arity
- = mkCoreUnfolding True (simpleOptExpr expr) arity
- (InlineRule { ir_sat = InlUnSat, ir_info = InlWrapper id })
+ = mkCoreUnfolding True (InlineWrapper id)
+ (simpleOptExpr expr) arity
+ (UnfWhen unSaturatedOk boringCxtNotOk)
mkCompulsoryUnfolding :: CoreExpr -> Unfolding
mkCompulsoryUnfolding expr -- Used for things that absolutely must be unfolded
- = mkCoreUnfolding True expr
- 0 -- Arity of unfolding doesn't matter
- (InlineRule { ir_info = InlAlways, ir_sat = InlUnSat })
+ = mkCoreUnfolding True InlineCompulsory
+ expr 0 -- Arity of unfolding doesn't matter
+ (UnfWhen unSaturatedOk boringCxtOk)
-mkInlineRule :: InlSatFlag -> CoreExpr -> Arity -> Unfolding
-mkInlineRule sat expr arity
- = mkCoreUnfolding True -- Note [Top-level flag on inline rules]
+mkInlineRule :: CoreExpr -> Maybe Arity -> Unfolding
+mkInlineRule expr mb_arity
+ = mkCoreUnfolding True InlineRule -- Note [Top-level flag on inline rules]
expr' arity
- (InlineRule { ir_sat = sat, ir_info = info })
+ (UnfWhen unsat_ok boring_ok)
where
expr' = simpleOptExpr expr
- info = if small then InlSmall else InlVanilla
- small = case calcUnfoldingGuidance (arity+1) expr' of
- (arity_e, UnfoldIfGoodArgs { ug_size = size_e })
- -> uncondInline arity_e size_e
- _other {- actually UnfoldNever -} -> False
+ (unsat_ok, arity) = case mb_arity of
+ Nothing -> (unSaturatedOk, manifestArity expr')
+ Just ar -> (needSaturated, ar)
+
+ boring_ok = case calcUnfoldingGuidance True -- Treat as cheap
+ False -- But not bottoming
+ (arity+1) expr' of
+ (_, UnfWhen _ boring_ok) -> boring_ok
+ _other -> boringCxtNotOk
+ -- See Note [INLINE for small functions]
\end{code}
\begin{code}
calcUnfoldingGuidance
- :: Int -- bomb out if size gets bigger than this
- -> CoreExpr -- expression to look at
+ :: Bool -- True <=> the rhs is cheap, or we want to treat it
+ -- as cheap (INLINE things)
+ -> Bool -- True <=> this is a top-level unfolding for a
+ -- diverging function; don't inline this
+ -> Int -- Bomb out if size gets bigger than this
+ -> CoreExpr -- Expression to look at
-> (Arity, UnfoldingGuidance)
-calcUnfoldingGuidance bOMB_OUT_SIZE expr
- = case collectBinders expr of { (binders, body) ->
+calcUnfoldingGuidance expr_is_cheap top_bot bOMB_OUT_SIZE expr
+ = case collectBinders expr of { (bndrs, body) ->
let
- val_binders = filter isId binders
- n_val_binders = length val_binders
+ val_bndrs = filter isId bndrs
+ n_val_bndrs = length val_bndrs
+
+ guidance
+ = case (sizeExpr (iUnbox bOMB_OUT_SIZE) val_bndrs body) of
+ TooBig -> UnfNever
+ SizeIs size cased_bndrs scrut_discount
+ | uncondInline n_val_bndrs (iBox size)
+ , expr_is_cheap
+ -> UnfWhen unSaturatedOk boringCxtOk -- Note [INLINE for small functions]
+ | top_bot -- See Note [Do not inline top-level bottoming functions]
+ -> UnfNever
+
+ | otherwise
+ -> UnfIfGoodArgs { ug_args = map (discount cased_bndrs) val_bndrs
+ , ug_size = iBox size
+ , ug_res = iBox scrut_discount }
+
+ discount cbs bndr
+ = foldlBag (\acc (b',n) -> if bndr==b' then acc+n else acc)
+ 0 cbs
in
- case (sizeExpr (iUnbox bOMB_OUT_SIZE) val_binders body) of
- TooBig -> (n_val_binders, UnfoldNever)
- SizeIs size cased_args scrut_discount
- -> (n_val_binders, UnfoldIfGoodArgs { ug_args = map discount_for val_binders
- , ug_size = iBox size
- , ug_res = iBox scrut_discount })
- where
- discount_for b = foldlBag (\acc (b',n) -> if b==b' then acc+n else acc)
- 0 cased_args
- }
+ (n_val_bndrs, guidance) }
\end{code}
Note [Computing the size of an expression]
a function call to account for. Notice also that constructor applications
are very cheap, because exposing them to a caller is so valuable.
-Note [Unconditional inlining]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-We inline *unconditionally* if inlined thing is smaller (using sizeExpr)
-than the thing it's replacing. Notice that
+
+Note [Do not inline top-level bottoming functions]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The FloatOut pass has gone to some trouble to float out calls to 'error'
+and similar friends. See Note [Bottoming floats] in SetLevels.
+Do not re-inline them! But we *do* still inline if they are very small
+(the uncondInline stuff).
+
+
+Note [INLINE for small functions]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider {-# INLINE f #-}
+ f x = Just x
+ g y = f y
+Then f's RHS is no larger than its LHS, so we should inline it into
+even the most boring context. In general, f the function is
+sufficiently small that its body is as small as the call itself, the
+inline unconditionally, regardless of how boring the context is.
+
+Things to note:
+
+ * We inline *unconditionally* if inlined thing is smaller (using sizeExpr)
+ than the thing it's replacing. Notice that
(f x) --> (g 3) -- YES, unconditionally
(f x) --> x : [] -- YES, *even though* there are two
-- arguments to the cons
x --> g 3 -- NO
x --> Just v -- NO
-It's very important not to unconditionally replace a variable by
-a non-atomic term.
+ It's very important not to unconditionally replace a variable by
+ a non-atomic term.
+
+* We do this even if the thing isn't saturated, else we end up with the
+ silly situation that
+ f x y = x
+ ...map (f 3)...
+ doesn't inline. Even in a boring context, inlining without being
+ saturated will give a lambda instead of a PAP, and will be more
+ efficient at runtime.
+
+* However, when the function's arity > 0, we do insist that it
+ has at least one value argument at the call site. Otherwise we find this:
+ f = /\a \x:a. x
+ d = /\b. MkD (f b)
+ If we inline f here we get
+ d = /\b. MkD (\x:b. x)
+ and then prepareRhs floats out the argument, abstracting the type
+ variables, so we end up with the original again!
+
\begin{code}
uncondInline :: Arity -> Int -> Bool
-- Inline unconditionally if there no size increase
-- Size of call is arity (+1 for the function)
--- See Note [Unconditional inlining]
+-- See Note [INLINE for small functions]
uncondInline arity size
| arity == 0 = size == 0
| otherwise = size <= arity + 1
-- discounts even on nullary constructors
size_up (App fun (Type _)) = size_up fun
- size_up (App fun arg) = size_up_app fun [arg]
- `addSize` nukeScrutDiscount (size_up arg)
+ 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)
| otherwise = size_up e
size_up (Let (NonRec binder rhs) body)
- = nukeScrutDiscount (size_up rhs) `addSize`
- size_up body `addSizeN`
+ = size_up rhs `addSizeNSD`
+ size_up body `addSizeN`
(if isUnLiftedType (idType binder) then 0 else 1)
-- For the allocation
-- If the binder has an unlifted type there is no allocation
size_up (Let (Rec pairs) body)
- = nukeScrutDiscount rhs_size `addSize`
- size_up body `addSizeN`
- length pairs -- For the allocation
- where
- rhs_size = foldr (addSize . size_up . snd) sizeZero pairs
+ = foldr (addSizeNSD . size_up . snd)
+ (size_up body `addSizeN` length pairs) -- (length pairs) for the allocation
+ pairs
size_up (Case (Var v) _ _ alts)
| v `elem` top_args -- We are scrutinising an argument variable
- = alts_size (foldr addSize sizeOne alt_sizes) -- The 1 is for the case itself
+ = alts_size (foldr1 addAltSize alt_sizes)
(foldr1 maxSize alt_sizes)
-- Good to inline if an arg is scrutinised, because
-- that may eliminate allocation in the caller
-- 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, iBox (_ILIT(1) +# tot -# max)) `unionBags` tot_disc) max_scrut
+ 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
-- 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) = foldr (addSize . size_up_alt)
- (nukeScrutDiscount (size_up e))
- alts
- `addSizeN` 1 -- Add 1 for the case itself
+ 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_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
- | otherwise = size_up_app fun (arg:args)
- `addSize` nukeScrutDiscount (size_up arg)
+ | otherwise = size_up arg `addSizeNSD`
+ size_up_app fun (arg:args)
size_up_app (Var fun) args = size_up_call fun args
size_up_app other args = size_up other `addSizeN` length args
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)
- = mkSizeIs bOMB_OUT_SIZE (n1 +# n2) (xs `unionBags` ys) (d1 +# d2)
+ -- addAltSize is used to add the sizes of case alternatives
+ addAltSize TooBig _ = TooBig
+ addAltSize _ TooBig = TooBig
+ addAltSize (SizeIs n1 xs d1) (SizeIs n2 ys d2)
+ = mkSizeIs bOMB_OUT_SIZE (n1 +# n2)
+ (xs `unionBags` ys)
+ (d1 +# d2) -- Note [addAltSize result discounts]
+
+ -- This variant ignores the result discount from its LEFT argument
+ -- It's used when the second argument isn't part of the result
+ addSizeNSD TooBig _ = TooBig
+ addSizeNSD _ TooBig = TooBig
+ addSizeNSD (SizeIs n1 xs _) (SizeIs n2 ys d2)
+ = mkSizeIs bOMB_OUT_SIZE (n1 +# n2)
+ (xs `unionBags` ys)
+ d2 -- Ignore d1
\end{code}
\begin{code}
-- Ditto (augment t (\cn -> e) ys) should cost only the cost of
-- e plus ys. The -2 accounts for the \cn
-nukeScrutDiscount :: ExprSize -> ExprSize
-nukeScrutDiscount (SizeIs n vs _) = SizeIs n vs (_ILIT(0))
-nukeScrutDiscount TooBig = TooBig
-
-- When we return a lambda, give a discount if it's used (applied)
lamScrutDiscount :: ExprSize -> ExprSize
lamScrutDiscount (SizeIs n vs _) = SizeIs n vs (iUnbox opt_UF_FunAppDiscount)
lamScrutDiscount TooBig = TooBig
\end{code}
+Note [addAltSize result discounts]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+When adding the size of alternatives, we *add* the result discounts
+too, rather than take the *maximum*. For a multi-branch case, this
+gives a discount for each branch that returns a constructor, making us
+keener to inline. I did try using 'max' instead, but it makes nofib
+'rewrite' and 'puzzle' allocate significantly more, and didn't make
+binary sizes shrink significantly either.
+
Note [Discounts and thresholds]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Constants for discounts and thesholds are defined in main/StaticFlags,
maxSize s1@(SizeIs n1 _ _) s2@(SizeIs n2 _ _) | n1 ># n2 = s1
| otherwise = s2
-sizeZero, sizeOne :: ExprSize
+sizeZero :: ExprSize
sizeN :: Int -> ExprSize
sizeZero = SizeIs (_ILIT(0)) emptyBag (_ILIT(0))
-sizeOne = SizeIs (_ILIT(1)) emptyBag (_ILIT(0))
sizeN n = SizeIs (iUnbox n) emptyBag (_ILIT(0))
\end{code}
-
-
%************************************************************************
%* *
\subsection[considerUnfolding]{Given all the info, do (not) do the unfolding}
\begin{code}
couldBeSmallEnoughToInline :: Int -> CoreExpr -> Bool
couldBeSmallEnoughToInline threshold rhs
- = case calcUnfoldingGuidance threshold rhs of
- (_, UnfoldNever) -> False
- _ -> True
+ = case sizeExpr (iUnbox threshold) [] body of
+ TooBig -> False
+ _ -> True
+ where
+ (_, body) = collectBinders rhs
----------------
smallEnoughToInline :: Unfolding -> Bool
-smallEnoughToInline (CoreUnfolding {uf_guidance = UnfoldIfGoodArgs {ug_size = size}})
+smallEnoughToInline (CoreUnfolding {uf_guidance = UnfIfGoodArgs {ug_size = size}})
= size <= opt_UF_UseThreshold
smallEnoughToInline _
= False
-- Sees if the unfolding is pretty certain to inline
certainlyWillInline (CoreUnfolding { uf_is_cheap = is_cheap, uf_arity = n_vals, uf_guidance = guidance })
= case guidance of
- UnfoldNever -> False
- InlineRule {} -> True
- UnfoldIfGoodArgs { ug_size = size}
+ UnfNever -> False
+ UnfWhen {} -> True
+ UnfIfGoodArgs { ug_size = size}
-> is_cheap && size - (n_vals +1) <= opt_UF_UseThreshold
certainlyWillInline _
\begin{code}
callSiteInline :: DynFlags
- -> Bool -- True <=> the Id can be inlined
-> Id -- The Id
+ -> Unfolding -- Its unfolding (if active)
-> Bool -- True if there are are no arguments at all (incl type args)
-> [ArgSummary] -- One for each value arg; True if it is interesting
-> CallCtxt -- True <=> continuation is interesting
ppr CaseCtxt = ptext (sLit "CaseCtxt")
ppr ValAppCtxt = ptext (sLit "ValAppCtxt")
-callSiteInline dflags active_inline id lone_variable arg_infos cont_info
- = let
- n_val_args = length arg_infos
- in
- case idUnfolding id of {
+callSiteInline dflags id unfolding lone_variable arg_infos cont_info
+ = case unfolding of {
NoUnfolding -> Nothing ;
OtherCon _ -> Nothing ;
DFunUnfolding {} -> Nothing ; -- Never unfold a DFun
-- uf_arity will typically be equal to (idArity id),
-- but may be less for InlineRules
let
+ n_val_args = length arg_infos
+ saturated = n_val_args >= uf_arity
+
result | yes_or_no = Just unf_template
| otherwise = Nothing
-- arguments (ie n_val_args >= arity). But there must
-- be *something* interesting about some argument, or the
-- result context, to make it worth inlining
- some_benefit = interesting_args
- || n_val_args > uf_arity -- Over-saturated
- || interesting_saturated_call -- Exactly saturated
+ some_benefit
+ | not saturated = interesting_args -- Under-saturated
+ -- Note [Unsaturated applications]
+ | n_val_args > uf_arity = True -- Over-saturated
+ | otherwise = interesting_args -- Saturated
+ || interesting_saturated_call
interesting_saturated_call
= case cont_info of
ArgCtxt {} -> uf_arity > 0 -- Note [Inlining in ArgCtxt]
ValAppCtxt -> True -- Note [Cast then apply]
- yes_or_no
+ (yes_or_no, extra_doc)
= case guidance of
- UnfoldNever -> False
-
- InlineRule { ir_info = inl_info, ir_sat = sat }
- | InlAlways <- inl_info -> True -- No top-level binding, so inline!
- -- Ignore is_active because we want to
- -- inline even if SimplGently is on.
- | not active_inline -> False
- | n_val_args < uf_arity -> yes_unsat -- Not enough value args
- | InlSmall <- inl_info -> True -- Note [INLINE for small functions]
- | otherwise -> some_benefit -- Saturated or over-saturated
- where
- -- See Note [Inlining an InlineRule]
- yes_unsat = case sat of
- InlSat -> False
- InlUnSat -> interesting_args
-
- UnfoldIfGoodArgs { ug_args = arg_discounts, ug_res = res_discount, ug_size = size }
- | not active_inline -> False
- | not is_cheap -> False
- | n_val_args < uf_arity -> interesting_args && small_enough
- -- Note [Unsaturated applications]
- | uncondInline uf_arity size -> True
- | otherwise -> some_benefit && small_enough
+ UnfNever -> (False, empty)
+ UnfWhen unsat_ok boring_ok
+ -> (enough_args && (boring_ok || some_benefit), empty )
+ where -- See Note [INLINE for small functions]
+ enough_args = saturated || (unsat_ok && n_val_args > 0)
+
+ UnfIfGoodArgs { ug_args = arg_discounts, ug_res = res_discount, ug_size = size }
+ -> ( is_cheap && some_benefit && small_enough
+ , (text "discounted size =" <+> int discounted_size) )
where
- small_enough = (size - discount) <= opt_UF_UseThreshold
+ discounted_size = size - discount
+ small_enough = discounted_size <= opt_UF_UseThreshold
discount = computeDiscount uf_arity arg_discounts
res_discount arg_infos cont_info
in
- if dopt Opt_D_dump_inlinings dflags then
+ if (dopt Opt_D_dump_inlinings dflags && dopt Opt_D_verbose_core2core dflags) then
pprTrace ("Considering inlining: " ++ showSDoc (ppr id))
- (vcat [text "active:" <+> ppr active_inline,
- text "arg infos" <+> ppr arg_infos,
+ (vcat [text "arg infos" <+> ppr arg_infos,
+ text "uf arity" <+> ppr uf_arity,
text "interesting continuation" <+> ppr cont_info,
+ text "some_benefit" <+> ppr some_benefit,
text "is value:" <+> ppr is_value,
text "is cheap:" <+> ppr is_cheap,
text "guidance" <+> ppr guidance,
+ extra_doc,
text "ANSWER =" <+> if yes_or_no then text "YES" else text "NO"])
result
else
order to unravel the recursion.
-Note [INLINE for small functions]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Consider {-# INLINE f #-}
- f x = Just x
- g y = f y
-Then f's RHS is no larger than its LHS, so we should inline it
-into even the most boring context. (We do so if there is no INLINE
-pragma!) That's the reason for the 'ug_small' flag on an InlineRule.
-
-
Note [Things to watch]
~~~~~~~~~~~~~~~~~~~~~~
* { y = I# 3; x = y `cast` co; ...case (x `cast` co) of ... }
Note [Inlining an InlineRule]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
An InlineRules is used for
- (a) pogrammer INLINE pragmas
+ (a) programmer INLINE pragmas
(b) inlinings from worker/wrapper
For (a) the RHS may be large, and our contract is that we *only* inline
-- | Returns @Just (dc, [t1..tk], [x1..xn])@ if the argument expression is
-- a *saturated* constructor application of the form @dc t1..tk x1 .. xn@,
-- where t1..tk are the *universally-qantified* type args of 'dc'
-exprIsConApp_maybe :: CoreExpr -> Maybe (DataCon, [Type], [CoreExpr])
+exprIsConApp_maybe :: IdUnfoldingFun -> CoreExpr -> Maybe (DataCon, [Type], [CoreExpr])
-exprIsConApp_maybe (Note _ expr)
- = exprIsConApp_maybe expr
+exprIsConApp_maybe id_unf (Note _ expr)
+ = exprIsConApp_maybe id_unf expr
-- We ignore all notes. For example,
-- case _scc_ "foo" (C a b) of
-- C a b -> e
-- should be optimised away, but it will be only if we look
-- through the SCC note.
-exprIsConApp_maybe (Cast expr co)
+exprIsConApp_maybe id_unf (Cast expr co)
= -- Here we do the KPush reduction rule as described in the FC paper
-- The transformation applies iff we have
-- (C e1 ... en) `cast` co
-- The left-hand one must be a T, because exprIsConApp returned True
-- but the right-hand one might not be. (Though it usually will.)
- case exprIsConApp_maybe expr of {
+ case exprIsConApp_maybe id_unf expr of {
Nothing -> Nothing ;
Just (dc, _dc_univ_args, dc_args) ->
Just (dc, to_tc_arg_tys, ex_args ++ new_co_args ++ new_val_args)
}}
-exprIsConApp_maybe expr
+exprIsConApp_maybe id_unf expr
= analyse expr []
where
analyse (App fun arg) args = analyse fun (arg:args)
-- Look through unfoldings, but only cheap ones, because
-- we are effectively duplicating the unfolding
- | CoreUnfolding { uf_expandable = expand_me, uf_tmpl = rhs } <- unfolding
- , expand_me = -- pprTrace "expanding" (ppr fun $$ ppr rhs) $
- analyse rhs args
+ | Just rhs <- expandUnfolding_maybe unfolding
+ = -- pprTrace "expanding" (ppr fun $$ ppr rhs) $
+ analyse rhs args
where
is_saturated = count isValArg args == idArity fun
- unfolding = idUnfolding fun
+ unfolding = id_unf fun
analyse _ _ = Nothing
-----------
- in_scope = mkInScopeSet (exprFreeVars expr)
-
- -----------
beta (Lam v body) pairs (arg : args)
| isTypeArg arg
= beta body ((v,arg):pairs) args
= Nothing
beta fun pairs args
- = case analyse (substExpr subst fun) args of
+ = case analyse (substExpr (text "subst-expr-is-con-app") subst fun) args of
Nothing -> -- pprTrace "Bale out! exprIsConApp_maybe" doc $
Nothing
Just ans -> -- pprTrace "Woo-hoo! exprIsConApp_maybe" doc $
Just ans
where
- subst = mkOpenSubst in_scope pairs
+ subst = mkOpenSubst (mkInScopeSet (exprFreeVars fun)) pairs
-- doc = vcat [ppr fun, ppr expr, ppr pairs, ppr args]
projects / ghc-hetmet.git / blobdiff