[commit: ghc] supercompiler: Give DataCons better tags (8a71f2f)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : supercompiler

http://hackage.haskell.org/trac/ghc/changeset/8a71f2f6c712ab02d04c03520991ea682b7a2daa

>---------------------------------------------------------------

commit 8a71f2f6c712ab02d04c03520991ea682b7a2daa
Author: Max Bolingbroke <[email protected]>
Date:   Tue Jan 3 13:53:13 2012 +0000

    Give DataCons better tags

>---------------------------------------------------------------

 compiler/supercompile/Supercompile/Core/Tag.hs |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/compiler/supercompile/Supercompile/Core/Tag.hs b/compiler/supercompile/Supercompile/Core/Tag.hs
index 33b9eb8..82951b9 100644
--- a/compiler/supercompile/Supercompile/Core/Tag.hs
+++ b/compiler/supercompile/Supercompile/Core/Tag.hs
@@ -10,6 +10,7 @@ import Supercompile.Core.Syntax
 
 import qualified DataCon
 import Literal (hashLiteral)
+import Var (varUnique)
 
 
 tagTerm :: UniqSupply -> Term -> TaggedTerm
@@ -25,7 +26,8 @@ tagFVedTerm = mkTagger (\tg e -> Comp (Tagged tg e))
 -- are specialised on very long repititions of the same constructor.
 
 dataConTag :: DataCon -> Tag
-dataConTag dc = mkTag (negate (DataCon.dataConTag dc)) -- Works well because (hashLiteral l) is always positive
+--dataConTag dc = mkTag (negate (DataCon.dataConTag dc)) -- Works well because (hashLiteral l) is always positive
+dataConTag = mkTag . getKey . varUnique . DataCon.dataConWorkId -- This is much better because otherwise [], True and all dictionary all get the same tag!!
 
 literalTag :: Literal -> Tag
 literalTag = mkTag . hashLiteral