FloatOutExample.hs

-- -fno-worker-wrapper -dno-typeable-binds just makes the resulting dump easier to understand.
-- Try uncommenting the second OPTIONS pragma to see the difference float out makes.
{-# OPTIONS_GHC -O -fno-worker-wrapper -ddump-simpl -dsuppress-all -ddump-to-file -fforce-recomp #-}
-- {-# OPTIONS_GHC -fno-full-laziness #-}

module Main(main,g) where

import GHC.Exts

{-# NOINLINE f #-}
f x y = x + y :: Int

g = map (\x -> f (nfib 15) x) [1..1000]

nfib :: Int -> Int
nfib n = if n <= 1 then 1 else nfib (n-1) + nfib (n-2) + 1

main = print $ sum g