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-- Reproducer for T17334
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE UnboxedTuples #-}
--Reproducer uses 64bit literals in reverseWord.
--It's ok to truncate those in x86
{-# OPTIONS_GHC -Wno-overflowed-literals #-}
module Bug (reverseInPlace) where
import Control.Monad.ST
import Data.Bits
import GHC.Exts
import GHC.ST (ST(..))
import Data.Kind
reverseInPlace :: PrimMonad m => UMVector (PrimState m) Bit -> m ()
reverseInPlace xs | len == 0 = pure ()
| otherwise = loop 0
where
len = ulength xs
loop !i
| i' <= j' = do
x <- readWord xs i
y <- readWord xs j'
writeWord xs i (reverseWord y)
writeWord xs j' (reverseWord x)
loop i'
| i' < j = do
let w = (j - i) `shiftR` 1
k = j - w
x <- readWord xs i
y <- readWord xs k
writeWord xs i (meld w (reversePartialWord w y) x)
writeWord xs k (meld w (reversePartialWord w x) y)
loop i'
| otherwise = do
let w = j - i
x <- readWord xs i
writeWord xs i (meld w (reversePartialWord w x) x)
where
!j = len - i
!i' = i + wordSize
!j' = j - wordSize
{-# SPECIALIZE reverseInPlace :: UMVector s Bit -> ST s () #-}
newtype Bit = Bit { unBit :: Bool }
instance Unbox Bit
data instance UMVector s Bit = BitMVec !Int !Int !(MutableByteArray s)
data instance UVector Bit = BitVec !Int !Int !ByteArray
readWord :: PrimMonad m => UMVector (PrimState m) Bit -> Int -> m Word
readWord !(BitMVec _ 0 _) _ = pure 0
readWord !(BitMVec off len' arr) !i' = do
let len = off + len'
i = off + i'
nMod = modWordSize i
loIx = divWordSize i
loWord <- readByteArray arr loIx
if nMod == 0
then pure loWord
else if loIx == divWordSize (len - 1)
then pure (loWord `unsafeShiftR` nMod)
else do
hiWord <- readByteArray arr (loIx + 1)
pure
$ (loWord `unsafeShiftR` nMod)
.|. (hiWord `unsafeShiftL` (wordSize - nMod))
{-# SPECIALIZE readWord :: UMVector s Bit -> Int -> ST s Word #-}
{-# INLINE readWord #-}
writeWord :: PrimMonad m => UMVector (PrimState m) Bit -> Int -> Word -> m ()
writeWord !(BitMVec _ 0 _) _ _ = pure ()
writeWord !(BitMVec off len' arr@(MutableByteArray mba)) !i' !x@(W# x#) = do
let len = off + len'
lenMod = modWordSize len
i = off + i'
nMod = modWordSize i
loIx@(I# loIx#) = divWordSize i
if nMod == 0
then if len >= i + wordSize
then primitive $ \state ->
(# atomicWriteIntArray# mba loIx# (word2Int# x#) state, () #)
else do
let W# andMask# = hiMask lenMod
W# orMask# = x .&. loMask lenMod
primitive $ \state ->
let !(# state', _ #) = fetchAndIntArray# mba loIx# (word2Int# andMask#) state in
let !(# state'', _ #) = fetchOrIntArray# mba loIx# (word2Int# orMask#) state' in
(# state'', () #)
else if loIx == divWordSize (len - 1)
then do
loWord <- readByteArray arr loIx
if lenMod == 0
then
writeByteArray arr loIx
$ (loWord .&. loMask nMod)
.|. (x `unsafeShiftL` nMod)
else
writeByteArray arr loIx
$ (loWord .&. (loMask nMod .|. hiMask lenMod))
.|. ((x `unsafeShiftL` nMod) .&. loMask lenMod)
else do
loWord <- readByteArray arr loIx
writeByteArray arr loIx
$ (loWord .&. loMask nMod)
.|. (x `unsafeShiftL` nMod)
hiWord <- readByteArray arr (loIx + 1)
writeByteArray arr (loIx + 1)
$ (hiWord .&. hiMask nMod)
.|. (x `unsafeShiftR` (wordSize - nMod))
{-# SPECIALIZE writeWord :: UMVector s Bit -> Int -> Word -> ST s () #-}
{-# INLINE writeWord #-}
instance GMVector UMVector Bit where
{-# INLINE basicLength #-}
basicLength (BitMVec _ n _) = n
instance GVector UVector Bit where
wordSize :: Int
wordSize = finiteBitSize (0 :: Word)
lgWordSize :: Int
lgWordSize = case wordSize of
32 -> 5
64 -> 6
_ -> error "wordsToBytes: unknown architecture"
divWordSize :: Bits a => a -> a
divWordSize x = unsafeShiftR x lgWordSize
{-# INLINE divWordSize #-}
modWordSize :: Int -> Int
modWordSize x = x .&. (wordSize - 1)
{-# INLINE modWordSize #-}
mask :: Int -> Word
mask b = m
where
m | b >= finiteBitSize m = complement 0
| b < 0 = 0
| otherwise = bit b - 1
meld :: Int -> Word -> Word -> Word
meld b lo hi = (lo .&. m) .|. (hi .&. complement m) where m = mask b
{-# INLINE meld #-}
reverseWord :: Word -> Word
reverseWord x0 = x6
where
x1 = ((x0 .&. 0x5555555555555555) `shiftL` 1) .|. ((x0 .&. 0xAAAAAAAAAAAAAAAA) `shiftR` 1)
x2 = ((x1 .&. 0x3333333333333333) `shiftL` 2) .|. ((x1 .&. 0xCCCCCCCCCCCCCCCC) `shiftR` 2)
x3 = ((x2 .&. 0x0F0F0F0F0F0F0F0F) `shiftL` 4) .|. ((x2 .&. 0xF0F0F0F0F0F0F0F0) `shiftR` 4)
x4 = ((x3 .&. 0x00FF00FF00FF00FF) `shiftL` 8) .|. ((x3 .&. 0xFF00FF00FF00FF00) `shiftR` 8)
x5 = ((x4 .&. 0x0000FFFF0000FFFF) `shiftL` 16) .|. ((x4 .&. 0xFFFF0000FFFF0000) `shiftR` 16)
x6 = ((x5 .&. 0x00000000FFFFFFFF) `shiftL` 32) .|. ((x5 .&. 0xFFFFFFFF00000000) `shiftR` 32)
reversePartialWord :: Int -> Word -> Word
reversePartialWord n w | n >= wordSize = reverseWord w
| otherwise = reverseWord w `shiftR` (wordSize - n)
loMask :: Int -> Word
loMask n = 1 `unsafeShiftL` n - 1
{-# INLINE loMask #-}
hiMask :: Int -> Word
hiMask n = complement (1 `unsafeShiftL` n - 1)
{-# INLINE hiMask #-}
class GMVector v a where
basicLength :: v s a -> Int
glength :: GMVector v a => v s a -> Int
{-# INLINE glength #-}
glength = basicLength
type family GMutable (v :: Type -> Type) :: Type -> Type -> Type
class GMVector (GMutable v) a => GVector v a
data family UMVector s a
data family UVector a
class (GVector UVector a, GMVector UMVector a) => Unbox a
type instance GMutable UVector = UMVector
ulength :: Unbox a => UMVector s a -> Int
{-# INLINE ulength #-}
ulength = glength
data ByteArray = ByteArray ByteArray#
data MutableByteArray s = MutableByteArray (MutableByteArray# s)
readByteArray
:: (Prim a, PrimMonad m) => MutableByteArray (PrimState m) -> Int -> m a
{-# INLINE readByteArray #-}
readByteArray (MutableByteArray arr#) (I# i#)
= primitive (readByteArray# arr# i#)
writeByteArray
:: (Prim a, PrimMonad m) => MutableByteArray (PrimState m) -> Int -> a -> m ()
{-# INLINE writeByteArray #-}
writeByteArray (MutableByteArray arr#) (I# i#) x
= primitive_ (writeByteArray# arr# i# x)
class Prim a where
readByteArray# :: MutableByteArray# s -> Int# -> State# s -> (# State# s, a #)
writeByteArray# :: MutableByteArray# s -> Int# -> a -> State# s -> State# s
instance Prim Word where
readByteArray# arr# i# s# = case readWordArray# arr# i# s# of
(# s1#, x# #) -> (# s1#, W# x# #)
writeByteArray# arr# i# (W# x#) s# = writeWordArray# arr# i# x# s#
class Monad m => PrimMonad m where
type PrimState m
primitive :: (State# (PrimState m) -> (# State# (PrimState m), a #)) -> m a
instance PrimMonad (ST s) where
type PrimState (ST s) = s
primitive = ST
{-# INLINE primitive #-}
primitive_ :: PrimMonad m
=> (State# (PrimState m) -> State# (PrimState m)) -> m ()
{-# INLINE primitive_ #-}
primitive_ f = primitive (\s# ->
case f s# of
s'# -> (# s'#, () #))
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