\section[SimplUtils]{The simplifier utilities}
\begin{code}
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
module SimplUtils (
-- Rebuilding
mkLam, mkCase, prepareAlts, bindCaseBndr,
import PprCore
import CoreFVs
import CoreUtils
-import Literal
import CoreUnfold
-import MkId
import Name
import Id
import Var ( isCoVar )
import Type hiding( substTy )
import Coercion ( coercionKind )
import TyCon
-import DataCon
import Unify ( dataConCannotMatch )
import VarSet
import BasicTypes
instance Outputable SimplCont where
ppr (Stop interesting) = ptext (sLit "Stop") <> brackets (ppr interesting)
- ppr (ApplyTo dup arg se cont) = ((ptext (sLit "ApplyTo") <+> ppr dup <+> pprParendExpr arg)
+ ppr (ApplyTo dup arg _ 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 (Select dup bndr alts se cont) = (ptext (sLit "Select") <+> ppr dup <+> ppr bndr) $$
+ ppr (Select dup bndr alts _ cont) = (ptext (sLit "Select") <+> ppr dup <+> ppr bndr) $$
(nest 4 (ppr alts)) $$ ppr cont
ppr (CoerceIt co cont) = (ptext (sLit "CoerceIt") <+> ppr co) $$ ppr cont
mkLazyArgStop cci = Stop cci
-------------------
-contIsRhsOrArg (Stop {}) = True
-contIsRhsOrArg (StrictBind {}) = True
-contIsRhsOrArg (StrictArg {}) = True
-contIsRhsOrArg other = False
+contIsRhsOrArg :: SimplCont -> Bool
+contIsRhsOrArg (Stop {}) = True
+contIsRhsOrArg (StrictBind {}) = True
+contIsRhsOrArg (StrictArg {}) = True
+contIsRhsOrArg _ = False
-------------------
contIsDupable :: SimplCont -> Bool
-contIsDupable (Stop {}) = True
+contIsDupable (Stop {}) = True
contIsDupable (ApplyTo OkToDup _ _ _) = True
contIsDupable (Select OkToDup _ _ _ _) = True
contIsDupable (CoerceIt _ cont) = contIsDupable cont
-contIsDupable other = False
+contIsDupable _ = False
-------------------
contIsTrivial :: SimplCont -> Bool
-contIsTrivial (Stop {}) = True
+contIsTrivial (Stop {}) = True
contIsTrivial (ApplyTo _ (Type _) _ cont) = contIsTrivial cont
-contIsTrivial (CoerceIt _ cont) = contIsTrivial cont
-contIsTrivial other = False
+contIsTrivial (CoerceIt _ cont) = contIsTrivial cont
+contIsTrivial _ = False
-------------------
contResultType :: SimplEnv -> OutType -> SimplCont -> OutType
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 (Stop {}) ty = ty
+ go (CoerceIt co cont) _ = go cont (snd (coercionKind co))
+ go (StrictBind _ bs body se cont) _ = go cont (subst_ty se (exprType (mkLams bs body)))
+ go (StrictArg fn _ _ cont) _ = go cont (funResultTy (exprType fn))
+ go (Select _ _ alts se cont) _ = 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
+ apply_to_arg ty _ _ = funResultTy ty
-------------------
countValArgs :: SimplCont -> Int
-countValArgs (ApplyTo _ (Type ty) se cont) = countValArgs cont
-countValArgs (ApplyTo _ val_arg se cont) = 1 + countValArgs cont
-countValArgs other = 0
+countValArgs (ApplyTo _ (Type _) _ cont) = countValArgs cont
+countValArgs (ApplyTo _ _ _ cont) = 1 + countValArgs cont
+countValArgs _ = 0
countArgs :: SimplCont -> Int
-countArgs (ApplyTo _ arg se cont) = 1 + countArgs cont
-countArgs other = 0
+countArgs (ApplyTo _ _ _ cont) = 1 + countArgs cont
+countArgs _ = 0
contArgs :: SimplCont -> ([OutExpr], SimplCont)
-- Uses substitution to turn each arg into an OutExpr
splitInlineCont cont@(Stop {}) = Just (mkBoringStop, cont)
splitInlineCont cont@(StrictBind {}) = Just (mkBoringStop, cont)
splitInlineCont cont@(StrictArg {}) = Just (mkBoringStop, cont)
-splitInlineCont other = Nothing
+splitInlineCont _ = Nothing
\end{code}
-- Lit lit -> True
-- _ -> False
-interestingArg other = True
+interestingArg _ = True
-- Consider let x = 3 in f x
-- The substitution will contain (x -> ContEx 3), and we want to
-- to say that x is an interesting argument.
arg_discounts = case idUnfolding fun of
CoreUnfolding _ _ _ _ (UnfoldIfGoodArgs _ discounts _ _)
-> discounts ++ vanilla_discounts
- other -> vanilla_discounts
+ _ -> vanilla_discounts
vanilla_stricts, arg_stricts :: [Bool]
vanilla_stricts = repeat False
-- 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 _ [] = []
add_type_str fun_ty strs -- Look through foralls
- | Just (tv, fun_ty') <- splitForAllTy_maybe fun_ty -- Includes coercions
+ | Just (_, 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
+ add_type_str _ strs
= strs
{- Note [Unsaturated functions]
go (Stop cci) = interesting cci
interesting (ArgCtxt rules _) = rules
- interesting other = False
+ interesting _ = False
\end{code}
| otherwise = case idOccInfo bndr of
IAmDead -> True -- Happens in ((\x.1) v)
OneOcc in_lam True int_cxt -> try_once in_lam int_cxt
- other -> False
+ _ -> False
where
phase = getMode env
active = case phase of
-- canInlineInLam => free vars of rhs are (Once in_lam) or Many,
-- so substituting rhs inside a lambda doesn't change the occ info.
-- Sadly, not quite the same as exprIsHNF.
- canInlineInLam (Lit l) = True
+ canInlineInLam (Lit _) = True
canInlineInLam (Lam b e) = isRuntimeVar b || canInlineInLam e
canInlineInLam (Note _ e) = canInlineInLam e
canInlineInLam _ = False
early_phase = case phase of
SimplPhase 0 _ -> False
- other -> True
+ _ -> True
-- If we don't have this early_phase test, consider
-- x = length [1,2,3]
-- The full laziness pass carefully floats all the cons cells to
-- True -> case x of ...
-- False -> case x of ...
-- I'm not sure how important this is in practice
- OneOcc in_lam one_br int_cxt -- OneOcc => no code-duplication issue
+ OneOcc in_lam _one_br int_cxt -- OneOcc => no code-duplication issue
-> smallEnoughToInline unfolding -- Small enough to dup
-- ToDo: consider discount on smallEnoughToInline if int_cxt is true
--
-- Here x isn't mentioned in the RHS, so we don't want to
-- create the (dead) let-binding let x = (a,b) in ...
- other -> False
+ _ -> False
-- Here's an example that we don't handle well:
-- let f = if b then Left (\x.BIG) else Right (\y.BIG)
| isLocalId fun = isEvaldUnfolding (idUnfolding fun)
| isDataConWorkId fun = True
| isGlobalId fun = idArity fun > 0
+ | otherwise = panic "tryEtaReduce/ok_fun_id"
ok_lam v = isTyVar v || isDictId v
imposs_cons = case scrut of
Var v -> otherCons (idUnfolding v)
- other -> []
+ _ -> []
impossible_alt :: CoreAlt -> Bool
impossible_alt (con, _, _) | con `elem` imposs_cons = True
impossible_alt (DataAlt con, _, _) = dataConCannotMatch inst_tys con
- impossible_alt alt = False
+ impossible_alt _ = False
--------------------------------------------------
--------------------------------------------------
combineIdenticalAlts :: OutId -> [InAlt] -> SimplM [InAlt]
-combineIdenticalAlts case_bndr alts@((con1,bndrs1,rhs1) : con_alts)
+combineIdenticalAlts case_bndr ((_con1,bndrs1,rhs1) : con_alts)
| all isDeadBinder bndrs1, -- Remember the default
length filtered_alts < length con_alts -- alternative comes first
-- Also Note [Dead binders]
; return ((DEFAULT, [], rhs1) : filtered_alts) }
where
filtered_alts = filter keep con_alts
- keep (con,bndrs,rhs) = not (all isDeadBinder bndrs && rhs `cheapEqExpr` rhs1)
+ keep (_con,bndrs,rhs) = not (all isDeadBinder bndrs && rhs `cheapEqExpr` rhs1)
-combineIdenticalAlts case_bndr alts = return alts
+combineIdenticalAlts _ alts = return alts
-------------------------------------------------------------------------
-- Prepare the default alternative
-- And becuase case-merging can cause many to show up
------- Merge nested cases ----------
-prepareDefault dflags env outer_bndr bndr_ty imposs_cons (Just deflt_rhs)
+prepareDefault dflags env outer_bndr _bndr_ty imposs_cons (Just deflt_rhs)
| dopt Opt_CaseMerge dflags
, Case (Var inner_scrut_var) inner_bndr _ inner_alts <- deflt_rhs
, DoneId inner_scrut_var' <- substId env inner_scrut_var
--------- Fill in known constructor -----------
-prepareDefault dflags env case_bndr (Just (tycon, inst_tys)) imposs_cons (Just deflt_rhs)
+prepareDefault _ _ case_bndr (Just (tycon, inst_tys)) imposs_cons (Just deflt_rhs)
| -- This branch handles the case where we are
-- scrutinisng an algebraic data type
isAlgTyCon tycon -- It's a data type, tuple, or unboxed tuples.
dataConRepInstPat us con inst_tys
; return [(DataAlt con, ex_tvs ++ co_tvs ++ arg_ids, deflt_rhs)] }
- two_or_more -> return [(DEFAULT, [], deflt_rhs)]
+ _ -> return [(DEFAULT, [], deflt_rhs)]
--------- Catch-all cases -----------
-prepareDefault dflags env case_bndr bndr_ty imposs_cons (Just deflt_rhs)
+prepareDefault _dflags _env _case_bndr _bndr_ty _imposs_cons (Just deflt_rhs)
= return [(DEFAULT, [], deflt_rhs)]
-prepareDefault dflags env case_bndr bndr_ty imposs_cons Nothing
+prepareDefault _dflags _env _case_bndr _bndr_ty _imposs_cons Nothing
= return [] -- No default branch
\end{code}
check_eq (LitAlt lit') _ (Lit lit) = lit == lit'
check_eq (DataAlt con) args rhs = rhs `cheapEqExpr` mkConApp con (arg_tys ++ varsToCoreExprs args)
|| rhs `cheapEqExpr` Var case_bndr
- check_eq con args rhs = False
+ check_eq _ _ _ = False
arg_tys = map Type (tyConAppArgs (idType case_bndr))
re_cast scrut = case head alts of
(_,_,Cast _ co) -> Cast scrut co
- other -> scrut
+ _ -> scrut
cascade rather nicely.
\begin{code}
+bindCaseBndr :: Id -> CoreExpr -> CoreExpr -> CoreExpr
bindCaseBndr bndr rhs body
| isDeadBinder bndr = body
- | otherwise = bindNonRec bndr rhs body
+ | otherwise = bindNonRec bndr rhs body
\end{code}
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