diff --git a/Numeric/AD/Internal/Reverse.hs b/Numeric/AD/Internal/Reverse.hs
--- a/Numeric/AD/Internal/Reverse.hs
+++ b/Numeric/AD/Internal/Reverse.hs
@@ -161,7 +161,7 @@
             forM_ (topSort g) $
                 backPropagate vmap ss
             return ss
-        sbounds ((a,_):as) = foldl' (\(lo,hi) (b,_) -> (min lo b, max hi b)) (a,a) as
+        sbounds ((a,_):as) = foldl' (\(lo,hi) (b,_) -> let lo' = min lo b; hi' = max hi b in lo' `seq` hi' `seq` (lo', hi')) (a,a) as
         sbounds _ = undefined -- the graph can't be empty, it contains the output node!
         edgeSet (i, t) = (t, i, successors t)
         nonConst (_, Lift{}) = False
diff --git a/ad.cabal b/ad.cabal
--- a/ad.cabal
+++ b/ad.cabal
@@ -1,5 +1,5 @@
 name:         ad
-version:      1.1.0.1
+version:      1.1.1
 license:      BSD3
 license-File: LICENSE
 copyright:    (c) Edward Kmett 2010-2011,