[project @ 1997-05-18 23:04:06 by sof]
[ghc-hetmet.git] / ghc / compiler / stranal / WorkWrap.lhs
index 251b7b2..e1621b3 100644 (file)
@@ -11,16 +11,16 @@ module WorkWrap ( workersAndWrappers ) where
 IMP_Ubiq(){-uitous-}
 
 import CoreSyn
-import CoreUnfold      ( Unfolding(..), UnfoldingGuidance(..), SimpleUnfolding )
-import MagicUFs                ( MagicUnfoldingFun )
+import CoreUnfold      ( Unfolding, certainlySmallEnoughToInline, calcUnfoldingGuidance )
+import CmdLineOpts     ( opt_UnfoldingCreationThreshold )
 
 import CoreUtils       ( coreExprType )
-import Id              ( idWantsToBeINLINEd, getIdStrictness, mkWorkerId,
-                         addIdStrictness, addInlinePragma,
-                         GenId
+import Id              ( getInlinePragma, getIdStrictness, mkWorkerId,
+                         addIdStrictness, addInlinePragma, 
+                         GenId, SYN_IE(Id)
                        )
-import IdInfo          ( noIdInfo, addInfo_UF, indicatesWorker,
-                         mkStrictnessInfo, StrictnessInfo(..)
+import IdInfo          ( noIdInfo, addUnfoldInfo,  
+                         mkStrictnessInfo, addStrictnessInfo, StrictnessInfo(..)
                        )
 import SaLib
 import UniqSupply      ( returnUs, thenUs, mapUs, getUnique, SYN_IE(UniqSM) )
@@ -175,8 +175,8 @@ reason), then we don't w-w it.
 The only reason this is monadised is for the unique supply.
 
 \begin{code}
-tryWW  :: Id                           -- the fn binder
-       -> CoreExpr             -- the bound rhs; its innards
+tryWW  :: Id                           -- The fn binder
+       -> CoreExpr                     -- The bound rhs; its innards
                                        --   are already ww'd
        -> UniqSM [(Id, CoreExpr)]      -- either *one* or *two* pairs;
                                        -- if one, then no worker (only
@@ -184,66 +184,50 @@ tryWW     :: Id                           -- the fn binder
                                        -- if two, then a worker and a
                                        -- wrapper.
 tryWW fn_id rhs
-  | idWantsToBeINLINEd fn_id
-    -- No point in worker/wrappering something that is going to be
-    -- INLINEd wholesale anyway.  If the strictness analyser is run
-    -- twice, this test also prevents wrappers (which are INLINEd)
-    -- from being re-done.
-  = do_nothing
-
-  | otherwise
-  = case (getIdStrictness fn_id) of
-
-      NoStrictnessInfo    -> do_nothing
-      BottomGuaranteed    -> do_nothing
-      StrictnessInfo [] _ -> do_nothing -- V weird (but possible?)
-
-      StrictnessInfo args_info _ ->
-       if not (indicatesWorker args_info) then
-           do_nothing
-       else
-
-       -- OK, it looks as if a worker is worth a try
-       let
-            (uvars, tyvars, args, body) = collectBinders rhs
-            body_ty                     = coreExprType body
-       in
-       mkWwBodies body_ty tyvars args args_info `thenUs` \ result ->
-       case result of
-
-         Nothing ->    -- Very peculiar. This can only happen if we hit an
-                       -- abstract type, which we shouldn't have since we've
-                       -- constructed the args_info in this module!
-
-                       -- False. We might hit the all-args-absent-and-the-
-                       -- body-is-unboxed case.  A Nothing is legit. (WDP 94/10)
-                       do_nothing
-
-         Just (wrapper_w_hole, worker_w_hole, worker_strictness, worker_ty_w_hole) ->
-
-               -- Terrific!  It worked!
-           getUnique           `thenUs` \ worker_uniq ->
-           let
-               worker_ty   = worker_ty_w_hole body_ty
-
-               worker_id   = mkWorkerId worker_uniq fn_id worker_ty
-                               (noIdInfo `addInfo` worker_strictness)
-
-               wrapper_rhs = wrapper_w_hole worker_id
-               worker_rhs  = worker_w_hole body
-
-               revised_strictness_info
-                 = -- We know the basic strictness info already, but
-                   -- we need to slam in the exact identity of the
-                   -- worker Id:
-                   mkStrictnessInfo args_info (Just worker_id)
-
-               wrapper_id  = addInlinePragma (fn_id `addIdStrictness`
-                                              revised_strictness_info)
-               -- NB the "addInlinePragma" part; we want to inline wrappers everywhere
-           in
-           returnUs [ (worker_id,  worker_rhs),   -- worker comes first
-                      (wrapper_id, wrapper_rhs) ] -- because wrapper mentions it
+  | (certainlySmallEnoughToInline $
+     calcUnfoldingGuidance (getInlinePragma fn_id) 
+                         opt_UnfoldingCreationThreshold
+                         rhs
+    )
+           -- No point in worker/wrappering something that is going to be
+           -- INLINEd wholesale anyway.  If the strictness analyser is run
+           -- twice, this test also prevents wrappers (which are INLINEd)
+           -- from being re-done.
+
+  || not has_strictness_info
+  || not (worthSplitting revised_wrap_args_info)
+  = returnUs [ (fn_id, rhs) ]
+
+  | otherwise          -- Do w/w split
+  = let
+       (uvars, tyvars, wrap_args, body) = collectBinders rhs
+    in
+    mkWwBodies tyvars wrap_args 
+              (coreExprType body)
+              revised_wrap_args_info           `thenUs` \ (wrap_fn, work_fn, work_demands) ->
+    getUnique                                  `thenUs` \ work_uniq ->
+    let
+       work_rhs  = work_fn body
+       work_id   = mkWorkerId work_uniq fn_id (coreExprType work_rhs) work_info
+       work_info = noIdInfo `addStrictnessInfo` mkStrictnessInfo work_demands Nothing
+
+       wrap_rhs = wrap_fn work_id
+       wrap_id  = addInlinePragma (fn_id `addIdStrictness`
+                                   mkStrictnessInfo revised_wrap_args_info (Just work_id))
+               -- Add info to the wrapper:
+               --      (a) we want to inline it everywhere
+               --      (b) we want to pin on its revised stricteness info
+               --      (c) we pin on its worker id
+    in
+    returnUs ([(work_id, work_rhs), (wrap_id, wrap_rhs)])
+       -- Worker first, because wrapper mentions it
   where
-    do_nothing = returnUs [ (fn_id, rhs) ]
+    strictness_info     = getIdStrictness fn_id
+    has_strictness_info = case strictness_info of
+                               StrictnessInfo _ _ -> True
+                               other              -> False
+
+    wrap_args_info = case strictness_info of
+                       StrictnessInfo args_info _ -> args_info
+    revised_wrap_args_info = setUnpackStrategy wrap_args_info
 \end{code}