64 bit windows executables compiled with ghc-7.8rc2 segfault when allocate more than 4G of memory

Consider this:

-- t.hs
import System.Environment

main :: IO ()
main = do
   n <- fmap (read . head) getArgs
   print $ foldr (+) (0::Int) [0 .. n]

Compiled with ghc-7.6.3 and ran thus:

ghc -O2 -rtsopts --make -o t.exe t.hs

t.exe +RTS -K4G -RTS 250000000

it works fine!

But compiled with 7.8rc2 it segfaults when amount of memory allocated crosses 4G mark.

I've discovered this trying to use Agda built with ghc-7.8rc2 but quickly understood this is a general problem and extremely nasty one.

Trac metadata

Trac field	Value
Version	7.8.1-rc2
Type	Bug
TypeOfFailure	OtherFailure
Priority	highest
Resolution	Unresolved
Component	Runtime System
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	simonmar
Operating system
Architecture