Ticket #4470: FunOpt.hs

{-# LANGUAGE BangPatterns #-}

module Main where

import Criterion.Main

f :: Int -> Int -> Int -> Int -> Int
f !i !j !s !m
  | i == 0    = s+m
  | otherwise = f (i-1) (j-1) (s + i+1) (m + j*5)

g :: Int -> Int
g !k = f k k 0 0


ff :: Int -> Int -> Int -> Int
ff !i !s !m
  | i == 0    = s+m
  | otherwise = ff (i-1) (s + i+1) (m + i*5)

gg :: Int -> Int
gg !k = ff k 0 0



{-
main = do
  print $ g 20
  print $ gg 20
-}

main = defaultMain
  [ bench " g" $ whnf g  20 -- 67.9ns
  , bench "gg" $ whnf gg 20 -- 64.5ns
  ]