1 files changed, 35 insertions, 0 deletions
diff --git a/testsuite/tests/numeric/should_run/numrun012.hs b/testsuite/tests/numeric/should_run/numrun012.hs
new file mode 100644
index 0000000000..18cef65e2f
--- /dev/null
+++ b/testsuite/tests/numeric/should_run/numrun012.hs
@@ -0,0 +1,35 @@
+
+-- Test for trac #921
+
+import GHC.Float
+import Foreign
+import Control.Monad
+
+main :: IO ()
+main = do -- The reported case
+          putStrLn (show (map log2 vals))
+          -- Smaller failing cases
+          print (fromIntegral ((2^31) :: Int) :: Double)
+          if_not_32 $ print (round ((2^33) :: Double) :: Int)
+          print (fromIntegral ((2^31) :: Int) :: Float)
+          if_not_32 $ print (round ((2^33) :: Float) :: Int)
+          -- The underlying failing internal operations
+          print (int2Double (2^31))
+          if_not_32 $ print (double2Int (2^33))
+          print (int2Float (2^31))
+          if_not_32 $ print (float2Int (2^33))
+  where
+    -- the value of float2Int x where the result would be outside the
+    -- range of the target is undefined.  We also take the view in GHC
+    -- that round and truncate are similarly undefined when the result
+    -- would be outside the range of the target type (see #1254)
+    if_not_32 = when (sizeOf (undefined::Int) > 4)
+
+log2 x = ceiling log_x
+    where log_x :: Double
+          log_x = logBase 2 (fromIntegral (max 1 x))
+
+vals = [1, 2, 17, 259, 1000, 10000,
+        2^30 + 9000, 2^31 - 1, 2^31 + 1,
+        2^32 - 1, 2^32 + 1]
+