diff --git a/ghc/lib/std/PrelNum.lhs b/ghc/lib/std/PrelNum.lhs
index 679329ab4d3f15576327d98fb10730e0b6ad0f43..0c7834a24752b12c0c1a2fc5e77977b60c88a531 100644
--- a/ghc/lib/std/PrelNum.lhs
+++ b/ghc/lib/std/PrelNum.lhs
@@ -848,7 +848,9 @@ jtos' n cs
   = if n < 10 then
 	chr (fromInteger (n + ord_0)) : cs
     else 
-	jtos' (n `quot` 10) (chr (toInt (n `rem` 10) + (ord_0::Int)) : cs)
+	jtos' q (chr (toInt r + (ord_0::Int)) : cs)
+  where
+    (q,r) = n `quotRem` 10
 
 showFloat x  =  showString (formatRealFloat FFGeneric Nothing x)