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|
{-# LANGUAGE BangPatterns, MagicHash, UnboxedTuples #-}
-- Test allocation of statically sized arrays. There's an optimization
-- that targets these and we want to make sure that the code generated
-- in the optimized case is correct.
--
-- The tests proceeds by allocating a bunch of arrays of different
-- sizes and reading elements from them, to try to provoke GC crashes,
-- which would be a symptom of the optimization not generating correct
-- code.
module Main where
import Control.Monad
import GHC.Exts
import GHC.IO
import Prelude hiding (read)
main :: IO ()
main = do
loop 1000
putStrLn "success"
where
loop :: Int -> IO ()
loop 0 = return ()
loop i = do
-- Sizes have been picked to match the triggering of the
-- optimization and to match boundary conditions. Sizes are
-- given explicitly as to not rely on other optimizations to
-- make the static size known to the compiler.
marr0 <- newArray 0
marr1 <- newArray 1
marr2 <- newArray 2
marr3 <- newArray 3
marr4 <- newArray 4
marr5 <- newArray 5
marr6 <- newArray 6
marr7 <- newArray 7
marr8 <- newArray 8
marr9 <- newArray 9
marr10 <- newArray 10
marr11 <- newArray 11
marr12 <- newArray 12
marr13 <- newArray 13
marr14 <- newArray 14
marr15 <- newArray 15
marr16 <- newArray 16
marr17 <- newArray 17
let marrs = [marr0, marr1, marr2, marr3, marr4, marr5, marr6, marr7,
marr8, marr9, marr10, marr11, marr12, marr13, marr14,
marr15, marr16, marr17]
total <- sumManyArrays marrs
unless (total == 153) $
putStrLn "incorrect sum"
loop (i-1)
sumManyArrays :: [MArray] -> IO Int
sumManyArrays = go 0
where
go !acc [] = return acc
go acc (marr:marrs) = do
n <- sumArray marr
go (acc+n) marrs
sumArray :: MArray -> IO Int
sumArray marr = go 0 0
where
go :: Int -> Int -> IO Int
go !acc i
| i < len = do
k <- read marr i
go (acc + k) (i+1)
| otherwise = return acc
len = lengthM marr
data MArray = MArray { unMArray :: !(MutableArray# RealWorld Int) }
newArray :: Int -> IO MArray
newArray (I# sz#) = IO $ \s -> case newArray# sz# 1 s of
(# s', marr #) -> (# s', MArray marr #)
{-# INLINE newArray #-} -- to make sure optimization triggers
lengthM :: MArray -> Int
lengthM marr = I# (sizeofMutableArray# (unMArray marr))
read :: MArray -> Int -> IO Int
read marr i@(I# i#)
| i < 0 || i >= len =
error $ "bounds error, offset " ++ show i ++ ", length " ++ show len
| otherwise = IO $ \ s -> readArray# (unMArray marr) i# s
where len = lengthM marr
|
