[project @ 2002-11-19 15:51:16 by simonpj]

[ghc-hetmet.git] / ghc / compiler / stranal / WwLib.lhs

diff --git a/ghc/compiler/stranal/WwLib.lhs b/ghc/compiler/stranal/WwLib.lhs
index 58060b0..49571f3 100644 (file)
--- a/ghc/compiler/stranal/WwLib.lhs
+++ b/ghc/compiler/stranal/WwLib.lhs
@@ -420,6 +420,9 @@ mkWWcpr body_ty RetCPR
 
     | n_con_args == 1 && isUnLiftedType con_arg_ty1
        -- Special case when there is a single result of unlifted type
+       --
+       -- Wrapper:     case (..call worker..) of x -> C x
+       -- Worker:      case (   ..body..    ) of C x -> x
     = getUniquesUs                     `thenUs` \ (work_uniq : arg_uniq : _) ->
       let
        work_wild = mk_ww_local work_uniq body_ty
@@ -431,6 +434,8 @@ mkWWcpr body_ty RetCPR
                con_arg_ty1)
 
     | otherwise                -- The general case
+       -- Wrapper: case (..call worker..) of (# a, b #) -> C a b
+       -- Worker:  case (   ...body...  ) of C a b -> (# a, b #)     
     = getUniquesUs             `thenUs` \ uniqs ->
       let
         (wrap_wild : work_wild : args) = zipWith mk_ww_local uniqs (ubx_tup_ty : body_ty : con_arg_tys)
@@ -440,7 +445,7 @@ mkWWcpr body_ty RetCPR
        ubx_tup_app                    = mkConApp ubx_tup_con (map Type con_arg_tys   ++ arg_vars)
         con_app                               = mkConApp data_con    (map Type tycon_arg_tys ++ arg_vars)
       in
-      returnUs (\ wkr_call -> Case wkr_call wrap_wild [(DataAlt ubx_tup_con, args, con_app)],
+      returnUs (\ wkr_call -> Case wkr_call wrap_wild   [(DataAlt ubx_tup_con, args, con_app)],
                \ body     -> workerCase body work_wild [(DataAlt data_con,    args, ubx_tup_app)],
                ubx_tup_ty)
     where