Segfault on x86 with -O2

[Kazu Yamamoto ( 山本和彦 )]

Hi,

Some changes in the last 8 days fixed segfault on 32bit x86 with -O2:

	http://ghc.haskell.org/trac/ghc/ticket/7953

I read recent log messages but I cannot guess which commits fixed this
bug. Does anyone guess?

P.S.

Thanks to this, now I started running Mighty with multicore IO manager
on mew.org. I'm watching whether or not multicore IO manager works
stably in the real world.

--Kazu