Remove dead code in the CPS pass

[ghc-hetmet.git] / compiler / simplCore / CSE.lhs

diff --git a/compiler/simplCore/CSE.lhs b/compiler/simplCore/CSE.lhs
index e7dd217..39344fc 100644 (file)
--- a/compiler/simplCore/CSE.lhs
+++ b/compiler/simplCore/CSE.lhs
@@ -19,6 +19,7 @@ import CoreSyn
 import VarEnv  
 import CoreLint                ( showPass, endPass )
 import Outputable
+import StaticFlags     ( opt_PprStyle_Debug )
 import BasicTypes      ( isAlwaysActive )
 import Util            ( mapAccumL, lengthExceeds )
 import UniqFM
@@ -314,11 +315,14 @@ 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 +334,7 @@ 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