X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FCSE.lhs;h=e0584ad1f6152b22424bff16b45727649658ee43;hb=ba00f074b38f4e168c893adc293c5b9cd6992721;hp=e7dd2175235cf3e5adeea63940bd039d4af7cba2;hpb=1ee8a6f6cf3c06e3651438720333612a70348091;p=ghc-hetmet.git

diff --git a/compiler/simplCore/CSE.lhs b/compiler/simplCore/CSE.lhs
index e7dd217..e0584ad 100644
--- a/compiler/simplCore/CSE.lhs
+++ b/compiler/simplCore/CSE.lhs
@@ -4,6 +4,13 @@
 \section{Common subexpression}
 
 \begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 module CSE (
 	cseProgram
     ) where
@@ -19,9 +26,12 @@ import CoreSyn
 import VarEnv	
 import CoreLint		( showPass, endPass )
 import Outputable
+import StaticFlags	( opt_PprStyle_Debug )
 import BasicTypes	( isAlwaysActive )
-import Util		( mapAccumL, lengthExceeds )
+import Util		( lengthExceeds )
 import UniqFM
+
+import Data.List
 \end{code}
 
 
@@ -161,7 +171,7 @@ Not CSE-ing inside INLINE also solves an annoying bug in CSE. Consider
 a worker/wrapper, in which the worker has turned into a single variable:
 	$wf = h
 	f = \x -> ...$wf...
-Now CSE may transoform to
+Now CSE may transform to
 	f = \x -> ...h...
 But the WorkerInfo for f still says $wf, which is now dead!  This won't
 happen now that we don't look inside INLINEs (which wrappers are).
@@ -314,11 +324,14 @@ addCSEnvItem env expr expr' | exprIsBig expr = env
 extendCSEnv (CS cs in_scope sub) expr expr'
   = CS (addToUFM_C combine cs hash [(expr, expr')]) in_scope sub
   where
-    hash   = hashExpr expr
-    combine old new = WARN( result `lengthExceeds` 4, text "extendCSEnv: long list:" <+> ppr result )
-		      result
-		    where
-		      result = new ++ old
+    hash = hashExpr expr
+    combine old new 
+	= WARN( result `lengthExceeds` 4, short_msg $$ nest 2 long_msg ) result
+	where
+	  result = new ++ old
+	  short_msg = ptext SLIT("extendCSEnv: long list, length") <+> int (length result)
+	  long_msg | opt_PprStyle_Debug = (text "hash code" <+> text (show hash)) $$ ppr result 
+		   | otherwise	        = empty
 
 lookupSubst (CS _ _ sub) x = case lookupVarEnv sub x of
 			       Just y  -> y
@@ -330,7 +343,7 @@ addBinder :: CSEnv -> Id -> (CSEnv, Id)
 addBinder env@(CS cs in_scope sub) v
   | not (v `elemInScopeSet` in_scope) = (CS cs (extendInScopeSet in_scope v)  sub,		       v)
   | isId v			      = (CS cs (extendInScopeSet in_scope v') (extendVarEnv sub v v'), v')
-  | not (isId v)		      = WARN( True, ppr v )
+  | otherwise			      = WARN( True, ppr v )
 				        (CS emptyUFM in_scope		      sub,		       v)
 	-- This last case is the unusual situation where we have shadowing of
 	-- a type variable; we have to discard the CSE mapping