#include "HsVersions.h"
-import Id ( Id, idName, idType, mkUserLocal, idCoreRules,
+import Id ( Id, idName, idType, mkUserLocal, idCoreRules, idUnfolding,
idInlineActivation, setInlineActivation, setIdUnfolding,
- isLocalId )
+ isLocalId, isDataConWorkId, idArity, setIdArity )
import TcType ( Type, mkTyVarTy, tcSplitSigmaTy,
tyVarsOfTypes, tyVarsOfTheta, isClassPred,
tcCmpType, isUnLiftedType
extendIdSubst
)
import CoreUnfold ( mkUnfolding )
-import SimplUtils ( interestingArg )
import Var ( DictId )
import VarSet
import VarEnv
where
fn_type = idType fn
+ fn_arity = idArity fn
(tyvars, theta, _) = tcSplitSigmaTy fn_type
n_tyvars = length tyvars
n_dicts = length theta
spec_id_ty = mkPiTypes lam_args body_ty
; spec_f <- newSpecIdSM fn spec_id_ty
+ ; let spec_f_w_arity = setIdArity spec_f (max 0 (fn_arity - n_dicts))
+ -- Adding arity information just propagates it a bit faster
+ -- See Note [Arity decrease] in Simplify
+
; (spec_rhs, rhs_uds) <- specExpr rhs_subst2 (mkLams lam_args body)
; let
-- The rule to put in the function's specialisation is:
(idName fn)
(poly_tyvars ++ inst_dict_ids)
inst_args
- (mkVarApps (Var spec_f) app_args)
+ (mkVarApps (Var spec_f_w_arity) app_args)
-- Add the { d1' = dx1; d2' = dx2 } usage stuff
final_uds = foldr addDictBind rhs_uds dx_binds
- spec_pr | inline_rhs = (spec_f `setInlineActivation` inline_act, Note InlineMe spec_rhs)
- | otherwise = (spec_f, spec_rhs)
+ spec_pr | inline_rhs = (spec_f_w_arity `setInlineActivation` inline_act, Note InlineMe spec_rhs)
+ | otherwise = (spec_f_w_arity, spec_rhs)
; return (Just (spec_pr, final_uds, spec_env_rule)) } }
where
-- *don't* say what the value of the implicit param is!
|| not (spec_tys `lengthIs` n_tyvars)
|| not ( dicts `lengthIs` n_dicts)
- || not (any interestingArg dicts) -- Note [Interesting dictionary arguments]
+ || not (any interestingDict dicts) -- Note [Interesting dictionary arguments]
-- See also Note [Specialisations already covered]
- = -- pprTrace "mkCallUDs: discarding" (vcat [ppr f, ppr args, ppr n_tyvars, ppr n_dicts, ppr (map interestingArg dicts)])
+ = -- pprTrace "mkCallUDs: discarding" (vcat [ppr f, ppr args, ppr n_tyvars, ppr n_dicts, ppr (map interestingDict dicts)])
emptyUDs -- Not overloaded, or no specialisation wanted
| otherwise
- = -- pprTrace "mkCallUDs: keeping" (vcat [ppr f, ppr args, ppr n_tyvars, ppr n_dicts, ppr (map interestingArg dicts)])
+ = -- pprTrace "mkCallUDs: keeping" (vcat [ppr f, ppr args, ppr n_tyvars, ppr n_dicts, ppr (map interestingDict dicts)])
singleCall f spec_tys dicts
where
(tyvars, theta, _) = tcSplitSigmaTy (idType f)
because the code for the specialised f is not improved at all, because
d is lambda-bound. We simply get junk specialisations.
-We re-use the function SimplUtils.interestingArg function to determine
-what sort of dictionary arguments have *some* information in them.
+What is "interesting"? Just that it has *some* structure.
+\begin{code}
+interestingDict :: CoreExpr -> Bool
+-- A dictionary argument is interesting if it has *some* structure
+interestingDict (Var v) = hasSomeUnfolding (idUnfolding v)
+ || isDataConWorkId v
+interestingDict (Type _) = False
+interestingDict (App fn (Type _)) = interestingDict fn
+interestingDict (Note _ a) = interestingDict a
+interestingDict (Cast e _) = interestingDict e
+interestingDict _ = True
+\end{code}
\begin{code}
plusUDs :: UsageDetails -> UsageDetails -> UsageDetails