copyArray# benchmark

gistfile1.hs

{-# LANGUAGE MagicHash, UnboxedTuples #-}
module Main (main) where

import Data.Time.Clock
import GHC.Exts
import GHC.IO
import GHC.Prim
import GHC.ST

bench = stToIO $ ST $ \ s ->
    case newArray# 32# 0 s of
        (# s2, marr #) -> case newArray# 32# 0 s2 of
            (# s3, marr2 #) -> case unsafeFreezeArray# marr2 s3 of
                (# s4, arr #) -> case copyArray# arr 0# marr 0# 32# s4 of
                    s5 -> (# s5, () #)

main = do start <- getCurrentTime
          go iters
          end <- getCurrentTime
          print $ (diffUTCTime end start) / fromIntegral iters
  where
    iters = 1000000 :: Int
    go 0 = return ()
    go n = bench >> go (n-1)