X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fstranal%2FWorkWrap.lhs;h=a1b18a98fb2d00266614aa2016b97e49dbc417cb;hb=2eb04ca0f8d0ec72b417cddc60672c696b4a3daa;hp=d964026756a178f7da9b6d9aaa83bbe2474d270d;hpb=302265d525004c7870864549f7a07a5759d32912;p=ghc-hetmet.git

diff --git a/compiler/stranal/WorkWrap.lhs b/compiler/stranal/WorkWrap.lhs
index d964026..a1b18a9 100644
--- a/compiler/stranal/WorkWrap.lhs
+++ b/compiler/stranal/WorkWrap.lhs
@@ -11,11 +11,11 @@ module WorkWrap ( wwTopBinds, mkWrapper ) where
 import CoreSyn
 import CoreUnfold	( certainlyWillInline )
 import CoreLint		( showPass, endPass )
-import CoreUtils	( exprType, exprIsHNF )
+import CoreUtils	( exprType, exprIsHNF, exprArity )
 import Id		( Id, idType, isOneShotLambda, 
 			  setIdNewStrictness, mkWorkerId,
 			  setIdWorkerInfo, setInlinePragma,
-			  idInfo )
+			  setIdArity, idInfo )
 import MkId		( lazyIdKey, lazyIdUnfolding )
 import Type		( Type )
 import IdInfo		( WorkerInfo(..), arityInfo,
@@ -26,7 +26,7 @@ import NewDemand        ( Demand(..), StrictSig(..), DmdType(..), DmdResult(..),
 			)
 import UniqSupply	( UniqSupply, initUs_, returnUs, thenUs, mapUs, getUniqueUs, UniqSM )
 import Unique		( hasKey )
-import BasicTypes	( RecFlag(..), isNonRec, Activation(..) )
+import BasicTypes	( RecFlag(..), isNonRec, isNeverActive )
 import VarEnv		( isEmptyVarEnv )
 import Maybes		( orElse )
 import DynFlags
@@ -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 ->
@@ -211,6 +215,11 @@ tryWW is_rec fn_id rhs
 	--	fw = \ab -> (__inline (\x -> E)) (a,b)
 	-- and the original __inline now vanishes, so E is no longer
 	-- inside its __inline wrapper.  Death!  Disaster!
+
+  || isNeverActive inline_prag
+	-- No point in worker/wrappering if the thing is never inlined!
+	-- Because the no-inline prag will prevent the wrapper ever
+	-- being inlined at a call site. 
   = returnUs [ (new_fn_id, rhs) ]
 
   | is_thunk && worthSplittingThunk maybe_fn_dmd res_info
@@ -256,14 +265,22 @@ splitFun fn_id fn_info wrap_dmds res_info inline_prag rhs
 	work_rhs = work_fn rhs
 	work_id  = mkWorkerId work_uniq fn_id (exprType work_rhs) 
 			`setInlinePragma` inline_prag
+				-- Any inline pragma (which sets when inlining is active) 
+				-- on the original function is duplicated on the worker and wrapper
+				-- It *matters* that the pragma stays on the wrapper
+				-- It seems sensible to have it on the worker too, although we
+				-- can't think of a compelling reason. (In ptic, INLINE things are 
+				-- not w/wd)
 			`setIdNewStrictness` StrictSig (mkTopDmdType work_demands work_res_info)
 				-- Even though we may not be at top level, 
 				-- it's ok to give it an empty DmdEnv
+                        `setIdArity` (exprArity work_rhs)
+                                -- Set the arity so that the Core Lint check that the 
+                                -- arity is consistent with the demand type goes through
 
 	wrap_rhs = wrap_fn work_id
 	wrap_id  = fn_id `setIdWorkerInfo` HasWorker work_id arity
-			 `setInlinePragma` AlwaysActive	-- Zap any inline pragma;
-							-- Put it on the worker instead
+
     in
     returnUs ([(work_id, work_rhs), (wrap_id, wrap_rhs)])
 	-- Worker first, because wrapper mentions it
@@ -308,7 +325,7 @@ splitThunk transforms like this:
 Now simplifier will transform to
 
       case x-rhs of 
-	I# a ->	let x* = I# b 
+	I# a ->	let x* = I# a 
 	        in body
 
 which is what we want. Now suppose x-rhs is itself a case: