SimplCont(..), DupFlag(..), ArgInfo(..),
contIsDupable, contResultType, contIsTrivial, contArgs, dropArgs,
countValArgs, countArgs, splitInlineCont,
- mkBoringStop, mkLazyArgStop, mkRhsStop, contIsRhsOrArg,
+ mkBoringStop, mkLazyArgStop, contIsRhsOrArg,
interestingCallContext, interestingArgContext,
interestingArg, mkArgInfo,
import NewDemand
import SimplMonad
import Type hiding( substTy )
+import Coercion ( coercionKind )
import TyCon
import DataCon
import Unify ( dataConCannotMatch )
\begin{code}
data SimplCont
= Stop -- An empty context, or hole, []
- OutType -- Type of the result
CallCtxt -- True <=> There is something interesting about
-- the context, and hence the inliner
-- should be a bit keener (see interestingCallContext)
SimplCont
| StrictArg -- e C
- OutExpr OutType -- e and its type
+ OutExpr -- e
CallCtxt -- Whether *this* argument position is interesting
ArgInfo -- Whether the function at the head of e has rules, etc
SimplCont -- plus strictness flags for *further* args
}
instance Outputable SimplCont where
- ppr (Stop ty _) = ptext SLIT("Stop") <+> ppr ty
+ ppr (Stop interesting) = ptext SLIT("Stop") <> brackets (ppr interesting)
ppr (ApplyTo dup arg se cont) = ((ptext SLIT("ApplyTo") <+> ppr dup <+> pprParendExpr arg)
{- $$ nest 2 (pprSimplEnv se) -}) $$ ppr cont
ppr (StrictBind b _ _ _ cont) = (ptext SLIT("StrictBind") <+> ppr b) $$ ppr cont
- ppr (StrictArg f _ _ _ cont) = (ptext SLIT("StrictArg") <+> ppr f) $$ ppr cont
+ ppr (StrictArg f _ _ cont) = (ptext SLIT("StrictArg") <+> ppr f) $$ ppr cont
ppr (Select dup bndr alts se cont) = (ptext SLIT("Select") <+> ppr dup <+> ppr bndr) $$
(nest 4 (ppr alts)) $$ ppr cont
ppr (CoerceIt co cont) = (ptext SLIT("CoerceIt") <+> ppr co) $$ ppr cont
-------------------
-mkBoringStop :: OutType -> SimplCont
-mkBoringStop ty = Stop ty BoringCtxt
+mkBoringStop :: SimplCont
+mkBoringStop = Stop BoringCtxt
-mkLazyArgStop :: OutType -> CallCtxt -> SimplCont
-mkLazyArgStop ty cci = Stop ty cci
-
-mkRhsStop :: OutType -> SimplCont
-mkRhsStop ty = Stop ty BoringCtxt
+mkLazyArgStop :: CallCtxt -> SimplCont
+mkLazyArgStop cci = Stop cci
-------------------
contIsRhsOrArg (Stop {}) = True
contIsTrivial other = False
-------------------
-contResultType :: SimplCont -> OutType
-contResultType (Stop to_ty _) = to_ty
-contResultType (StrictArg _ _ _ _ cont) = contResultType cont
-contResultType (StrictBind _ _ _ _ cont) = contResultType cont
-contResultType (ApplyTo _ _ _ cont) = contResultType cont
-contResultType (CoerceIt _ cont) = contResultType cont
-contResultType (Select _ _ _ _ cont) = contResultType cont
+contResultType :: SimplEnv -> OutType -> SimplCont -> OutType
+contResultType env ty cont
+ = go cont ty
+ where
+ subst_ty se ty = substTy (se `setInScope` env) ty
+
+ go (Stop {}) ty = ty
+ go (CoerceIt co cont) ty = go cont (snd (coercionKind co))
+ go (StrictBind _ bs body se cont) ty = go cont (subst_ty se (exprType (mkLams bs body)))
+ go (StrictArg fn _ _ cont) ty = go cont (funResultTy (exprType fn))
+ go (Select _ _ alts se cont) ty = go cont (subst_ty se (coreAltsType alts))
+ go (ApplyTo _ arg se cont) ty = go cont (apply_to_arg ty arg se)
+
+ apply_to_arg ty (Type ty_arg) se = applyTy ty (subst_ty se ty_arg)
+ apply_to_arg ty other se = funResultTy ty
-------------------
countValArgs :: SimplCont -> Int
-- See test simpl017 (and Trac #1627) for a good example of why this is important
splitInlineCont (ApplyTo dup (Type ty) se c)
- | Just (c1, c2) <- splitInlineCont c = Just (ApplyTo dup (Type ty) se c1, c2)
-splitInlineCont cont@(Stop ty _) = Just (mkBoringStop ty, cont)
-splitInlineCont cont@(StrictBind bndr _ _ se _) = Just (mkBoringStop (substTy se (idType bndr)), cont)
-splitInlineCont cont@(StrictArg _ fun_ty _ _ _) = Just (mkBoringStop (funArgTy fun_ty), cont)
+ | Just (c1, c2) <- splitInlineCont c = Just (ApplyTo dup (Type ty) se c1, c2)
+splitInlineCont cont@(Stop {}) = Just (mkBoringStop, cont)
+splitInlineCont cont@(StrictBind {}) = Just (mkBoringStop, cont)
+splitInlineCont cont@(StrictArg {}) = Just (mkBoringStop, cont)
splitInlineCont other = Nothing
- -- NB: the calculation of the type for mkBoringStop is an annoying
- -- duplication of the same calucation in mkDupableCont
\end{code}
-- seen (coerce f) x, where f has an INLINE prag,
-- So we have to give some motivation for inlining it
- interesting (StrictArg _ _ cci _ _) = cci
+ interesting (StrictArg _ cci _ _) = cci
interesting (StrictBind {}) = BoringCtxt
- interesting (Stop ty cci) = cci
+ interesting (Stop cci) = cci
interesting (CoerceIt _ cont) = interesting cont
-- If this call is the arg of a strict function, the context
-- is a bit interesting. If we inline here, we may get useful
, ai_discs = vanilla_discounts }
| otherwise
= ArgInfo { ai_rules = interestingArgContext fun call_cont
- , ai_strs = arg_stricts
+ , ai_strs = add_type_str (idType fun) arg_stricts
, ai_discs = arg_discounts }
where
vanilla_discounts, arg_discounts :: [Int]
map isStrictDmd demands -- Finite => result is bottom
else
map isStrictDmd demands ++ vanilla_stricts
-
| otherwise
-> WARN( True, text "More demands than arity" <+> ppr fun <+> ppr (idArity fun)
<+> ppr n_val_args <+> ppr demands )
vanilla_stricts -- Not enough args, or no strictness
+ add_type_str :: Type -> [Bool] -> [Bool]
+ -- If the function arg types are strict, record that in the 'strictness bits'
+ -- No need to instantiate because unboxed types (which dominate the strict
+ -- types) can't instantiate type variables.
+ -- add_type_str is done repeatedly (for each call); might be better
+ -- once-for-all in the function
+ -- But beware primops/datacons with no strictness
+ add_type_str fun_ty [] = []
+ add_type_str fun_ty strs -- Look through foralls
+ | Just (tv, fun_ty') <- splitForAllTy_maybe fun_ty -- Includes coercions
+ = add_type_str fun_ty' strs
+ add_type_str fun_ty (str:strs) -- Add strict-type info
+ | Just (arg_ty, fun_ty') <- splitFunTy_maybe fun_ty
+ = (str || isStrictType arg_ty) : add_type_str fun_ty' strs
+ add_type_str fun_ty strs
+ = strs
+
{- Note [Unsaturated functions]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider (test eyeball/inline4)
interestingArgContext fn call_cont
= idHasRules fn || go call_cont
where
- go (Select {}) = False
- go (ApplyTo {}) = False
- go (StrictArg _ _ cci _ _) = interesting cci
- go (StrictBind {}) = False -- ??
- go (CoerceIt _ c) = go c
- go (Stop _ cci) = interesting cci
+ go (Select {}) = False
+ go (ApplyTo {}) = False
+ go (StrictArg _ cci _ _) = interesting cci
+ go (StrictBind {}) = False -- ??
+ go (CoerceIt _ c) = go c
+ go (Stop cci) = interesting cci
interesting (ArgCtxt rules _) = rules
interesting other = False
-> Bool
postInlineUnconditionally env top_lvl bndr occ_info rhs unfolding
| not active = False
- | isLoopBreaker occ_info = False -- If it's a loop-breaker of any kind, dont' inline
+ | isLoopBreaker occ_info = False -- If it's a loop-breaker of any kind, don't inline
-- because it might be referred to "earlier"
| isExportedId bndr = False
| exprIsTrivial rhs = True
However for GlobalIds we can look at the arity; and for primops we
must, since they have no unfolding.
-* Regardless of whether 'f' is a vlaue, we always want to
+* Regardless of whether 'f' is a value, we always want to
reduce (/\a -> f a) to f
This came up in a RULE: foldr (build (/\a -> g a))
- did not match foldr (build (/\b -> ...something complex...))
+ did not match foldr (build (/\b -> ...something complex...))
The type checker can insert these eta-expanded versions,
with both type and dictionary lambdas; hence the slightly
ad-hoc isDictId
We'd like to float this to
y1 = /\a. e1
y2 = /\a. e2
- x = /\a. C (y1 a) (y2 a)
+ x = /\a. C (y1 a) (y2 a)
for the usual reasons: we want to inline x rather vigorously.
You may think that this kind of thing is rare. But in some programs it is
\begin{code}
-mkCase :: OutExpr -> OutId -> OutType
- -> [OutAlt] -- Increasing order
+mkCase :: OutExpr -> OutId -> [OutAlt] -- Increasing order
-> SimplM OutExpr
--------------------------------------------------
--- 1. Check for empty alternatives
---------------------------------------------------
-
--- This isn't strictly an error. It's possible that the simplifer might "see"
--- that an inner case has no accessible alternatives before it "sees" that the
--- entire branch of an outer case is inaccessible. So we simply
--- put an error case here insteadd
-mkCase scrut case_bndr ty []
- = pprTrace "mkCase: null alts" (ppr case_bndr <+> ppr scrut) $
- return (mkApps (Var rUNTIME_ERROR_ID)
- [Type ty, Lit (mkStringLit "Impossible alternative")])
-
-
---------------------------------------------------
-- 2. Identity case
--------------------------------------------------
-mkCase scrut case_bndr ty alts -- Identity case
+mkCase scrut case_bndr alts -- Identity case
| all identity_alt alts
= do tick (CaseIdentity case_bndr)
return (re_cast scrut)
--------------------------------------------------
-- Catch-all
--------------------------------------------------
-mkCase scrut bndr ty alts = return (Case scrut bndr ty alts)
+mkCase scrut bndr alts = return (Case scrut bndr (coreAltsType alts) alts)
\end{code}
projects / ghc-hetmet.git / blobdiff