ghc-4.02 treats sum strangely.
In the below program, sum xs needs small, constant size stack,
sm xs needs stack proportional to length xs.
And sm is the implementation of sum shown in src/.../PrelList.lhs
I apply ghc -c -O.
What keys are needed to code sum like it is in this
ghc-4.02-linux-i386-unknown binary?
Generally, how to make the compiler to save stack in the simplest
functions, like sum, specialized to Integer?
(apart of strictness annotations).
------------------
Sergey Mechveliani
[EMAIL PROTECTED]
-------------------------------------
sm = foldl (+) 0
{-# SPECIALISE sm :: [Int] -> Int #-}
main = let xs = [1..789000] :: [Int]
s1 = sum xs
s2 = sm xs
in putStr (shows s2 "\n")
