1 files changed, 39 insertions, 0 deletions
diff --git a/testsuite/tests/lib/integer/integerRecipMod.hs b/testsuite/tests/lib/integer/integerRecipMod.hs
new file mode 100644
index 0000000000..e5de646790
--- /dev/null
+++ b/testsuite/tests/lib/integer/integerRecipMod.hs
@@ -0,0 +1,39 @@
+{-# LANGUAGE BangPatterns, CPP, MagicHash, UnboxedTuples, TupleSections #-}
+
+module Main (main) where
+
+import Data.List (group)
+import Data.Bits
+import Data.Word
+import Data.Maybe
+import Control.Monad
+
+import GHC.Word
+import GHC.Base
+import GHC.Num.Integer
+import qualified GHC.Num.Integer as I
+
+recipModInteger :: Integer -> Integer -> Maybe Integer
+recipModInteger x m = case I.integerRecipMod# x m of
+   (# y |    #) -> Just y
+   (#   | () #) -> Nothing
+
+main :: IO ()
+main = do
+   let
+      f x = case recipModInteger x (2*3*11*11*17*17) of
+               y -> fmap (x,) y
+
+      g x = case recipModInteger x (-2*3*11*11*17*17) of
+               y -> fmap (x,) y
+
+   -- positive modulo
+   print $ mapMaybe f [-7..71]
+
+   -- negative modulo
+   print $ mapMaybe g [-7..71]
+
+   -- modulo == 1, -1 or 0
+   print (recipModInteger 77 1)
+   print (recipModInteger 77 (-1))
+   print (recipModInteger 77 0)