diff --git a/hashtables.cabal b/hashtables.cabal
--- a/hashtables.cabal
+++ b/hashtables.cabal
@@ -1,5 +1,5 @@
 Name:                hashtables
-Version:             1.1.2.0
+Version:             1.1.2.1
 Synopsis:            Mutable hash tables in the ST monad
 Homepage:            http://github.com/gregorycollins/hashtables
 License:             BSD3
diff --git a/src/Data/HashTable/Internal/CacheLine.hs b/src/Data/HashTable/Internal/CacheLine.hs
--- a/src/Data/HashTable/Internal/CacheLine.hs
+++ b/src/Data/HashTable/Internal/CacheLine.hs
@@ -42,7 +42,14 @@
 import           Data.HashTable.Internal.Utils
 import           GHC.Exts
 
+#if __GLASGOW_HASKELL__ >= 707
+import GHC.Exts (isTrue#)
+#else
+isTrue# :: Bool -> Bool
+isTrue# = id
+#endif
 
+
 {-# INLINE prefetchRead  #-}
 {-# INLINE prefetchWrite #-}
 prefetchRead :: IntArray s -> Int -> ST s ()
@@ -183,7 +190,7 @@
 
 {-# INLINE isCacheLineAligned #-}
 isCacheLineAligned :: Int -> Bool
-isCacheLineAligned (I# x#) = r# ==# 0#
+isCacheLineAligned (I# x#) = isTrue# (r# ==# 0#)
   where
     !(I# m#) = cacheLineIntMask
     !mw#     = int2Word# m#