Double literals generated bad core

The following code results in core containing expression like doubleFromInteger (wordToInteger sc_s2pw):

{-# LANGUAGE CPP, BangPatterns #-}
module Main (main) where

#define VDIM 100
#define VNUM 100000

import Data.Array.Base
import Data.Array.ST
import Data.Array.Unboxed
import Control.Monad.ST
import GHC.Word
import Control.Monad
import Data.Bits

prng :: Word -> Word
prng w = w'
  where
    !w1 = w `xor` (w `shiftL` 13)
    !w2 = w1 `xor` (w1 `shiftR` 7)
    !w' = w2 `xor` (w2 `shiftL` 17)

type Vec s = STUArray s Int Double

kahan :: Vec s -> Vec s -> ST s ()
kahan s c = do
    let inner w j
            | j < VDIM  = do
                !cj <- unsafeRead c j
                !sj <- unsafeRead s j
                let !y = fromIntegral w - cj
                    !t = sj + y
                    !w' = prng w
                unsafeWrite c j ((t-sj)-y)
                unsafeWrite s j t
                inner w' (j+1)
            | otherwise = return ()
        outer i | i < VNUM = inner i 0 >> outer (i + 1)
                | otherwise = return ()
    outer 0

calc :: ST s (Vec s)
calc = do
    s <- newArray (0,VDIM-1) 0
    c <- newArray (0,VDIM-1) 0
    kahan s c
    return s

main :: IO ()
main = print . elems $ runSTUArray calc

Trac metadata

Trac field	Value
Version	7.4.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	johan.tibell@gmail.com
Operating system
Architecture