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-- 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]
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