ffi005 fails on OS X

[igloo]

The ffi005 test is failing on OS X x86.

The test is only run the optc way, but we get other bad results when compiling in other ways.

normal:

{-# LANGUAGE ForeignFunctionInterface #-}

import Control.Monad
import Foreign.C

main :: IO ()
main = doit sin mysin (encodeFloat 7926335344172077 (-54))

doit :: (CDouble -> CDouble) -> (CDouble -> CDouble) -> CDouble -> IO ()
doit f g x = do let fx = f x
                    gx = g x
                when (fx /= gx) $ do print x
                                     print (decodeFloat x)
                                     print fx
                                     print gx
                                     print (fx - gx)

foreign import ccall "sin" mysin :: CDouble -> CDouble

$ ghc q.hs -o q; ./q
0.4400000000000002
(7926335344172077,-54)
0.4259394650659998
0.42593946506599983
-5.551115123125783e-17

optc:

{-# LANGUAGE ForeignFunctionInterface #-}

import Control.Monad
import Foreign
import Foreign.C

main :: IO ()
main = do sin_addr <- wrapId sin
          doit sin (dyn_sin sin_addr) (encodeFloat 7926335344172077 (-54))
          freeHaskellFunPtr sin_addr

doit :: (CDouble -> CDouble) -> (CDouble -> CDouble) -> CDouble -> IO ()
doit f g x = do let fx = f x
                    gx = g x
                when (fx /= gx) $ do print x
                                     print (decodeFloat x)
                                     print fx
                                     print gx
                                     print (fx - gx)

foreign import ccall "wrapper" wrapId :: (CDouble -> CDouble) -> IO (FunPtr (CDouble -> CDouble))
foreign import ccall "dynamic" dyn_sin :: FunPtr (CDouble -> CDouble) -> (CDouble -> CDouble)

$ ghc w.hs -o w -fvia-c -O; ./w
0.4400000000000002
(7926335344172077,-54)
0.42593946506599983
0.4259394650659998
5.551115123125783e-17

optasm:

{-# LANGUAGE ForeignFunctionInterface #-}

import Control.Monad
import Foreign
import Foreign.C

main :: IO ()
main = do sin_addr <- wrapId sin
          doit sin (dyn_sin sin_addr) (encodeFloat 7926335344172077 (-54))
          freeHaskellFunPtr sin_addr

doit :: (CDouble -> CDouble) -> (CDouble -> CDouble) -> CDouble -> IO ()
doit f g x = do let fx = f x
                    gx = g x
                when (fx /= gx) $ do print x
                                     print (decodeFloat x)
                                     print fx
                                     print gx
                                     print (decodeFloat fx)
                                     print (decodeFloat gx)
                                     print (fx == gx)
                                     print (decodeFloat fx == decodeFloat gx)
                                     print (fx - gx)

foreign import ccall "wrapper" wrapId :: (CDouble -> CDouble) -> IO (FunPtr (CDouble -> CDouble))
foreign import ccall "dynamic" dyn_sin :: FunPtr (CDouble -> CDouble) -> (CDouble -> CDouble)

$ ghc r.hs -o r -O; ./r
0.4400000000000002
(7926335344172077,-54)
0.4259394650659998
0.4259394650659998
(7673043264614500,-54)
(7673043264614500,-54)
False
True
0.0