[project @ 1999-06-28 16:29:45 by simonpj]

* Add Type.repType

* Re-express splitRepTyConApp_maybe using repType

* Use the new repType in Core2Stg

	The bug was that we ended up with a binding like
		let x = /\a -> 3# +# y
		in ...
	and this should turn into an STG case, but the big lambda
	fooled the core-to-STG pass

ghc/compiler/codeGen/CgCase.lhs

 %
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
-% $Id: CgCase.lhs,v 1.33 1999/06/24 13:04:16 simonmar Exp $
+% $Id: CgCase.lhs,v 1.34 1999/06/28 16:29:45 simonpj Exp $
 %
 %********************************************************
 %*							*
@@ -62,7 +62,7 @@ import TyCon		( TyCon, isEnumerationTyCon, isUnboxedTupleTyCon,
 			  isNewTyCon, isAlgTyCon, isFunTyCon, isPrimTyCon,
 			  tyConDataCons, tyConFamilySize )
 import Type		( Type, typePrimRep, splitAlgTyConApp, 
-			  splitTyConApp_maybe, splitRepTyConApp_maybe )
+			  splitTyConApp_maybe, repType )
 import Unique           ( Unique, Uniquable(..), mkBuiltinUnique )
 import Maybes		( maybeToBool )
 import Util
@@ -981,7 +981,7 @@ possibleHeapCheck NoGC	_ _ tags lbl code
 \begin{code}
 getScrutineeTyCon :: Type -> Maybe TyCon
 getScrutineeTyCon ty =
-   case splitRepTyConApp_maybe ty of
+   case splitTyConApp_maybe (repType ty) of
 	Nothing -> Nothing
 	Just (tc,_) -> 
 		if isFunTyCon tc  then Nothing else     -- not interested in funs

ghc/compiler/codeGen/CgExpr.lhs

 %
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
-% $Id: CgExpr.lhs,v 1.28 1999/06/24 13:04:18 simonmar Exp $
+% $Id: CgExpr.lhs,v 1.29 1999/06/28 16:29:45 simonpj Exp $
 %
 %********************************************************
 %*							*
@@ -48,7 +48,7 @@ import PrimOp		( primOpOutOfLine,
 import PrimRep		( getPrimRepSize, PrimRep(..), isFollowableRep )
 import TyCon		( maybeTyConSingleCon,
 			  isUnboxedTupleTyCon, isEnumerationTyCon )
-import Type		( Type, typePrimRep, splitTyConApp_maybe, splitRepTyConApp_maybe )
+import Type		( Type, typePrimRep, splitTyConApp_maybe, repType )
 import Maybes		( assocMaybe, maybeToBool )
 import Unique		( mkBuiltinUnique )
 import BasicTypes	( TopLevelFlag(..), RecFlag(..) )
@@ -462,7 +462,7 @@ primRetUnboxedTuple op args res_ty
       allocate some temporaries for the return values.
     -}
     let
-      (tc,ty_args)      = case splitRepTyConApp_maybe res_ty of
+      (tc,ty_args)      = case splitTyConApp_maybe (repType res_ty) of
 			    Nothing -> pprPanic "primRetUnboxedTuple" (ppr res_ty)
 			    Just pr -> pr
       prim_reps          = map typePrimRep ty_args

ghc/compiler/stgSyn/CoreToStg.lhs

@@ -34,7 +34,7 @@ import Const	        ( Con(..), Literal(..), isLitLitLit, conStrictness, isWHNFC
 import VarEnv
 import PrimOp		( PrimOp(..), primOpUsg, primOpSig )
 import Type		( isUnLiftedType, isUnboxedTupleType, Type, splitFunTy_maybe,
-                          UsageAnn(..), tyUsg, applyTy, mkUsgTy )
+                          UsageAnn(..), tyUsg, applyTy, mkUsgTy, repType )
 import TysPrim		( intPrimTy )
 import UniqSupply	-- all of it, really
 import Util		( lengthExceeds )
@@ -813,10 +813,10 @@ mkStgBind (NonRecF bndr rhs dem floats) body
 
 mk_stg_let bndr rhs dem floats body
 #endif
-  | isUnLiftedType bndr_ty			-- Use a case/PrimAlts
-  = ASSERT( not (isUnboxedTupleType bndr_ty) )
+  | isUnLiftedType bndr_rep_ty			-- Use a case/PrimAlts
+  = ASSERT( not (isUnboxedTupleType bndr_rep_ty) )
     mkStgBinds floats $
-    mkStgCase rhs bndr (StgPrimAlts bndr_ty [] (StgBindDefault body))
+    mkStgCase rhs bndr (StgPrimAlts bndr_rep_ty [] (StgBindDefault body))
 
   | is_whnf
   = if is_strict then
@@ -836,19 +836,19 @@ mk_stg_let bndr rhs dem floats body
   = if is_strict then
 	-- Strict let with non-WHNF rhs
 	mkStgBinds floats $
-	mkStgCase rhs bndr (StgAlgAlts bndr_ty [] (StgBindDefault body))
+	mkStgCase rhs bndr (StgAlgAlts bndr_rep_ty [] (StgBindDefault body))
     else
 	-- Lazy let with non-WHNF rhs, so keep the floats in the RHS
 	mkStgBinds floats rhs		`thenUs` \ new_rhs ->
 	returnUs (StgLet (StgNonRec bndr (exprToRhs dem NotTopLevel new_rhs)) body)
 	
   where
-    bndr_ty   = idType bndr
-    is_strict = isStrictDem dem
-    is_whnf   = case rhs of
-		  StgCon _ _ _ -> True
-		  StgLam _ _ _ -> True
-		  other	       -> False
+    bndr_rep_ty = repType (idType bndr)
+    is_strict   = isStrictDem dem
+    is_whnf     = case rhs of
+		    StgCon _ _ _ -> True
+		    StgLam _ _ _ -> True
+		    other	 -> False
 
 -- Split at the first strict binding
 splitFloats fs@(NonRecF _ _ dem _ : _) 

ghc/compiler/types/Type.lhs

@@ -29,10 +29,10 @@ module Type (
 	zipFunTys,
 
 	mkTyConApp, mkTyConTy, splitTyConApp_maybe,
-	splitAlgTyConApp_maybe, splitAlgTyConApp, splitRepTyConApp_maybe,
+	splitAlgTyConApp_maybe, splitAlgTyConApp, 
 	mkDictTy, splitDictTy_maybe, isDictTy,
 
-	mkSynTy, isSynTy, deNoteType,
+	mkSynTy, isSynTy, deNoteType, repType,
 
         mkUsgTy, isUsgTy{- dont use -}, isNotUsgTy, splitUsgTy, unUsgTy, tyUsg,
 
@@ -529,27 +529,6 @@ isDictTy (NoteTy _ ty)	= isDictTy ty
 isDictTy other		= False
 \end{code}
 
-splitRepTyConApp_maybe is like splitTyConApp_maybe except
-that it looks through 
-	(a) for-alls, and
-	(b) newtypes
-in addition to synonyms.  It's useful in the back end where we're not
-interested in newtypes anymore.
-
-\begin{code}
-splitRepTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
-splitRepTyConApp_maybe (FunTy arg res)   = Just (funTyCon, [arg,res])
-splitRepTyConApp_maybe (NoteTy _ ty)     = splitRepTyConApp_maybe ty
-splitRepTyConApp_maybe (ForAllTy _ ty)   = splitRepTyConApp_maybe ty
-splitRepTyConApp_maybe (TyConApp tc tys) 
-	| isNewTyCon tc	
-	= case splitFunTy_maybe (applyTys (dataConType (head (tyConDataCons tc))) tys) of
-		Just (rep_ty, _) -> splitRepTyConApp_maybe rep_ty
-	| otherwise
-	= Just (tc,tys)
-splitRepTyConApp_maybe other	         = Nothing
-\end{code}
-
 ---------------------------------------------------------------------
 				SynTy
 				~~~~~
@@ -592,6 +571,23 @@ interfaces.  Notably this plays a role in tcTySigs in TcBinds.lhs.
 
 
 
+repType looks through 
+	(a) for-alls, and
+	(b) newtypes
+in addition to synonyms.  It's useful in the back end where we're not
+interested in newtypes anymore.
+
+\begin{code}
+repType :: Type -> Type
+repType (NoteTy _ ty)     = repType ty
+repType (ForAllTy _ ty)   = repType ty
+repType (TyConApp tc tys) | isNewTyCon tc	
+			  = case splitFunTy_maybe (applyTys (dataConType (head (tyConDataCons tc))) tys) of
+				Just (rep_ty, _) -> repType rep_ty
+repType other_ty	  = other_ty
+\end{code}
+
+
 
 ---------------------------------------------------------------------
 				UsgNote