Here is a test program (file name prgSrc.hs):

import Data.Array.Unboxed

main = do
  let l1 = [1..10] :: [Int]
  let l2 = [ map (i+) l1 | i <- [1..5000000] ]
  let l3 = map (\l -> listArray (1,length l) l) l2 :: [UArray Int Int]
  print $ accumulate l3 0

accumulate [] rv = rv
accumulate (h:t) rv =
  let nextRv = (rv + sum (elems h)) in
  accumulate t $! nextRv

I used ghc 7.0.3-2 on archlinux, 64 bit version. I created it only to check how much memory short unboxed arrays consume. Thanks to the "$!" call at the last line of the "accumulate" function there should not be any stack overflow.

When I compile with these options:[[BR]] ghc --make prgSrc.hs[[BR]] ghc -O2 --make prgSrc.hs[[BR]] ghc -prof -auto-all -caf-all --make prgSrc.hs[[BR]] then there is no problem.

But when I compile with these options:[[BR]] ghc -O2 -prof -auto-all -caf-all --make prgSrc.hs[[BR]] then the program runs out of stack.

This indicates that there is a bug while compiling "$!" in an optimized profiling version of this program.