Massive patch for the first months work adding System FC to GHC #33

Broken up massive patch -=chak
Original log message:  
This is (sadly) all done in one patch to avoid Darcs bugs.
It's not complete work... more FC stuff to come.  A compiler
using just this patch will fail dismally.

3 files changed, 26 insertions, 11 deletions

diff --git a/compiler/stranal/DmdAnal.lhs b/compiler/stranal/DmdAnal.lhs
index 127fa7800f..3fc84773af 100644
--- a/compiler/stranal/DmdAnal.lhs
+++ b/compiler/stranal/DmdAnal.lhs
@@ -40,7 +40,8 @@ import TysWiredIn	( unboxedPairDataCon )
 import TysPrim		( realWorldStatePrimTy )
 import UniqFM		( plusUFM_C, addToUFM_Directly, lookupUFM_Directly,
 			  keysUFM, minusUFM, ufmToList, filterUFM )
-import Type		( isUnLiftedType, coreEqType )
+import Type		( isUnLiftedType, coreEqType, splitTyConApp_maybe )
+import Coercion         ( coercionKind )
 import CoreLint		( showPass, endPass )
 import Util		( mapAndUnzip, mapAccumL, mapAccumR, lengthIs )
 import BasicTypes	( Arity, TopLevelFlag(..), isTopLevel, isNeverActive,
@@ -164,16 +165,25 @@ dmdAnal sigs dmd (Lit lit)
 dmdAnal sigs dmd (Var var)
   = (dmdTransform sigs var dmd, Var var)
 
+dmdAnal sigs dmd (Cast e co)
+  = (dmd_ty, Cast e' co)
+  where
+    (dmd_ty, e') = dmdAnal sigs dmd' e
+    to_co        = snd (coercionKind co)
+    dmd'
+      | Just (tc, args) <- splitTyConApp_maybe to_co
+      , isRecursiveTyCon tc = evalDmd
+      | otherwise           = dmd
+	-- This coerce usually arises from a recursive
+        -- newtype, and we don't want to look inside them
+	-- for exactly the same reason that we don't look
+	-- inside recursive products -- we might not reach
+	-- a fixpoint.  So revert to a vanilla Eval demand
+
 dmdAnal sigs dmd (Note n e)
   = (dmd_ty, Note n e')
   where
-    (dmd_ty, e') = dmdAnal sigs dmd' e	
-    dmd' = case n of
-	     Coerce _ _ -> evalDmd  -- This coerce usually arises from a recursive
-	     other	-> dmd 	    -- newtype, and we don't want to look inside them
-				    -- for exactly the same reason that we don't look
-				    -- inside recursive products -- we might not reach
-				    -- a fixpoint.  So revert to a vanilla Eval demand
+    (dmd_ty, e') = dmdAnal sigs dmd e	
 
 dmdAnal sigs dmd (App fun (Type ty))
   = (fun_ty, App fun' (Type ty))
diff --git a/compiler/stranal/WorkWrap.lhs b/compiler/stranal/WorkWrap.lhs
index 29702cf9f3..2f5d38c069 100644
--- a/compiler/stranal/WorkWrap.lhs
+++ b/compiler/stranal/WorkWrap.lhs
@@ -153,6 +153,10 @@ wwExpr (Note note expr)
   = wwExpr expr			`thenUs` \ new_expr ->
     returnUs (Note note new_expr)
 
+wwExpr (Cast expr co)
+  = wwExpr expr			`thenUs` \ new_expr ->
+    returnUs (Cast new_expr co)
+
 wwExpr (Let bind expr)
   = wwBind bind			`thenUs` \ intermediate_bind ->
     wwExpr expr			`thenUs` \ new_expr ->
diff --git a/compiler/stranal/WwLib.lhs b/compiler/stranal/WwLib.lhs
index e44e521c83..f3af6f0395 100644
--- a/compiler/stranal/WwLib.lhs
+++ b/compiler/stranal/WwLib.lhs
@@ -22,6 +22,7 @@ import TysWiredIn	( tupleCon )
 import Type		( Type, isUnLiftedType, mkFunTys,
 			  splitForAllTys, splitFunTys, splitRecNewType_maybe, isAlgType
 			)
+import Coercion         ( Coercion, mkSymCoercion, splitRecNewTypeCo_maybe )
 import BasicTypes	( Boxity(..) )
 import Var              ( Var, isId )
 import UniqSupply	( returnUs, thenUs, getUniquesUs, UniqSM )
@@ -223,7 +224,7 @@ mkWWargs :: Type
 		     Type)			-- Type of wrapper body
 
 mkWWargs fun_ty demands one_shots
-  | Just rep_ty <- splitRecNewType_maybe fun_ty
+  | Just (rep_ty, co) <- splitRecNewTypeCo_maybe fun_ty
    	-- The newtype case is for when the function has
 	-- a recursive newtype after the arrow (rare)
 	-- We check for arity >= 0 to avoid looping in the case
@@ -236,8 +237,8 @@ mkWWargs fun_ty demands one_shots
 	-- simply coerces.
   = mkWWargs rep_ty demands one_shots	`thenUs` \ (wrap_args, wrap_fn_args, work_fn_args, res_ty) ->
     returnUs (wrap_args,
-	      Note (Coerce fun_ty rep_ty) . wrap_fn_args,
-	      work_fn_args . Note (Coerce rep_ty fun_ty),
+	      \ e -> Cast (wrap_fn_args e) co,
+	      \ e -> work_fn_args (Cast e (mkSymCoercion co)),
 	      res_ty)
 
   | notNull demands