diff --git a/ghc/lib/glaExts/Addr.lhs b/ghc/lib/glaExts/Addr.lhs
index 91056eea7e231312e074b2a4f59f0ed8a703ddb3..c592d50a9f08700a7bd4b32edf3c604408538ec2 100644
--- a/ghc/lib/glaExts/Addr.lhs
+++ b/ghc/lib/glaExts/Addr.lhs
@@ -22,6 +22,9 @@ import CCall
 \begin{code}
 data Addr = A# Addr# 	deriving (Eq, Ord)
 
+instance Show Addr where
+   showsPrec p (A# a) = showsPrec p (I# (addr2Int# a))
+
 nullAddr = ``NULL'' :: Addr
 
 plusAddr :: Addr -> Int -> Addr