ghc 5.04.2 and seg fault

Greetings,

I have a bug which I'm having trouble reproducing on a small scale, so
I'm not sure how to proceed to get more information to you.

When I use ghc --make to recompile a group of files, I sometimes get a
segfault when running the target program.  If I remove all of the .o
files and compile again, I do not get the segfault.  If I remove just
the changed .o files and the executable and recompile, I still get the
segfault.  

I'm not using any unsafe IO as far as I know, though I am using Happy
and Alex.

I searched around for a while about methods for debugging ghc, but
didn't find much.  It doesn't look like its a gc bug since I tried
giving a big heap size and had no effect.  Can I rebuild ghc or my
target program in some way to get more debugging information to you?
Unfortunately, I can't post my entire program.


peace,

isaac