Improve hashing of expressions for CSE (reduces warnings about extendCSEnv)

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

diff --git a/compiler/simplCore/CSE.lhs b/compiler/simplCore/CSE.lhs
index e7dd217..f8259c7 100644 (file)
--- a/compiler/simplCore/CSE.lhs
+++ b/compiler/simplCore/CSE.lhs
@@ -315,7 +315,9 @@ 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 )
+    combine old new = WARN( result `lengthExceeds` 4, ((text "extendCSEnv: long list (length" <+> int (length result) <> comma 
+                                                       <+> text "hash code" <+> text (show hash) <> char ')')
+                                                       $$ nest 4 (ppr result)) )
                      result
                    where
                      result = new ++ old