X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fspecialise%2FSpecialise.lhs;h=64d0cdd7a32b22f0db065def2264d273ffed1692;hb=f73446118d7168e238868b591be748ab0997045c;hp=015332f0408d3f5e1d73f3bd706ac667da47fc30;hpb=4bc25e8c30559b7a6a87b39afcc79340ae778788;p=ghc-hetmet.git

diff --git a/compiler/specialise/Specialise.lhs b/compiler/specialise/Specialise.lhs
index 015332f..64d0cdd 100644
--- a/compiler/specialise/Specialise.lhs
+++ b/compiler/specialise/Specialise.lhs
@@ -14,9 +14,9 @@ module Specialise ( specProgram ) where
 
 #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
@@ -27,7 +27,6 @@ import CoreSubst	( Subst, mkEmptySubst, extendTvSubstList, lookupIdSubst,
 			  extendIdSubst
 			) 
 import CoreUnfold	( mkUnfolding )
-import SimplUtils	( interestingArg )
 import Var		( DictId )
 import VarSet
 import VarEnv
@@ -826,6 +825,7 @@ specDefn subst calls fn rhs
   
   where
     fn_type	       = idType fn
+    fn_arity	       = idArity fn
     (tyvars, theta, _) = tcSplitSigmaTy fn_type
     n_tyvars	       = length tyvars
     n_dicts	       = length theta
@@ -906,6 +906,10 @@ specDefn subst calls fn rhs
 	         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:
@@ -917,13 +921,13 @@ specDefn subst calls fn rhs
 			 	  (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
@@ -1195,13 +1199,13 @@ mkCallUDs f args
 	--  *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)
@@ -1225,9 +1229,19 @@ There really is not much point in specialising f wrt the dictionary d,
 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