diff --git a/NEWS b/NEWS
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,7 @@
+Changes in 0.5.0:
+
+* GHC 7.8.1 compatability
+
 Changes in 0.4.1:
 
 * added indexOf/getIndexOf
diff --git a/lib/Data/IntArray.hs b/lib/Data/IntArray.hs
--- a/lib/Data/IntArray.hs
+++ b/lib/Data/IntArray.hs
@@ -1,4 +1,5 @@
-{-# LANGUAGE MagicHash, UnboxedTuples #-}
+
+{-# LANGUAGE MagicHash, UnboxedTuples, CPP #-}
 {-# OPTIONS_GHC -funbox-strict-fields #-}
 -----------------------------------------------------------------------------
 -- |
@@ -39,6 +40,14 @@
 import GHC.ST
 import Foreign( sizeOf )
 
+#if __GLASGOW_HASKELL__ >= 708
+import GHC.Exts (isTrue#)
+
+isTrue = isTrue#
+#else
+isTrue = id
+#endif 
+{-# INLINE isTrue #-}
 -----------------------------  Immutable arrays -----------------------------
 
 data IntArray = IntArray !Int (ByteArray#)
@@ -75,8 +84,8 @@
 {-# INLINE sameSTIntArray #-}
 sameSTIntArray :: STIntArray s -> STIntArray s -> Bool
 sameSTIntArray (STIntArray _ marr1#) (STIntArray _ marr2#) =
-    sameMutableByteArray# marr1# marr2#
-    
+    isTrue (sameMutableByteArray# marr1# marr2#)
+
 {-# INLINE numElementsSTIntArray #-}
 numElementsSTIntArray :: STIntArray s -> Int
 numElementsSTIntArray (STIntArray n _) = n
@@ -109,15 +118,15 @@
                 case readIntArray#  marr# j# s2# of { (# s3#, f# #) ->
                 case writeIntArray# marr# i# f# s3# of { s4# ->
                      writeIntArray# marr# j# e# s4# }}} in
-        if i# ==# j# then (# s1#, () #)
-                     else case doSwap of { s2# ->
-                          (# s2#, () #) }
+        if isTrue (i# ==# j#) then (# s1#, () #)
+                              else case doSwap of { s2# ->
+                                   (# s2#, () #) }
 
 {-# INLINE readElems #-}
 readElems :: STIntArray s -> ST s [Int]
 readElems (STIntArray (I# n#) marr#) =
     ST $ \s1# ->
-        let inlineReadList i# | i# ==# n# = []
+        let inlineReadList i# | isTrue (i# ==# n#) = []
                               | otherwise = 
                 case readIntArray# marr# i# s1# of { (# _, e# #) ->
                 let e  = I# e#
@@ -130,7 +139,7 @@
 writeElems :: STIntArray s -> [Int] -> ST s ()
 writeElems (STIntArray (I# n#) marr#) es =
     ST $ \s1# ->
-        let fillFromList i# xs s2# | i# ==# n# = s2#
+        let fillFromList i# xs s2# | isTrue (i# ==# n#) = s2#
                                    | otherwise = case xs of
                 []         -> s2#
                 (I# y#):ys -> case writeIntArray# marr# i# y# s2# of { s3# ->
diff --git a/lib/Data/Permute/MPermute.hs b/lib/Data/Permute/MPermute.hs
--- a/lib/Data/Permute/MPermute.hs
+++ b/lib/Data/Permute/MPermute.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE BangPatterns, MultiParamTypeClasses, FunctionalDependencies, 
-        FlexibleContexts #-}
+        FlexibleContexts, CPP #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module     : Data.Permute.MPermute
@@ -78,8 +78,12 @@
 
 import Control.Monad
 import Control.Monad.ST
+#if __GLASGOW_HASKELL__ >= 708
+import Control.Monad.ST.Unsafe
+#endif
 import Data.Function( on )
 import qualified Data.List as List
+
 import System.IO.Unsafe( unsafeInterleaveIO )
 
 import Data.Permute.Base
diff --git a/permutation.cabal b/permutation.cabal
--- a/permutation.cabal
+++ b/permutation.cabal
@@ -1,6 +1,6 @@
 name:            permutation
-version:         0.4.1
-homepage:        http://stat.stanford.edu/~patperry/code/permutation
+version:         0.5.0.5
+homepage:        https://github.com/spacekitteh/permutation
 synopsis:        A library for permutations and combinations.
 description:
     This library includes data types for storing permutations and
@@ -22,10 +22,10 @@
 license-file:    LICENSE
 copyright:       (c) 2008. Patrick Perry <patperry@stanford.edu>
 author:          Patrick Perry
-maintainer:      Patrick Perry <patperry@stanford.edu>
+maintainer:      Sophie Taylor <sophie@traumapony.org>
 cabal-version: >= 1.2.3
 build-type:      Custom
-tested-with:     GHC ==6.8.2, GHC ==6.10.1
+tested-with:     GHC ==7.8.1
 
 extra-source-files:  examples/Enumerate.hs
                      tests/Test/Choose.hs
@@ -56,16 +56,17 @@
                      Data.Permute.Base
                      Data.Permute.IOBase
 
-    build-depends:   base
+    build-depends:   base < 5 && >=4, QuickCheck
     extensions:      BangPatterns, 
                      FlexibleContexts,
                      FunctionalDependencies, 
                      MagicHash,
                      MultiParamTypeClasses, 
                      Rank2Types,
-                     UnboxedTuples
+                     UnboxedTuples,
+                     CPP
 
-    ghc-options:     -Wall
+    ghc-options:     -Wall -O3
 
     if impl(ghc >= 6.9)
       build-depends: ghc-prim