Hi Eli,
Corinna has asked me to take a look at your bug report[1] on this
problem (since she has now encountered it in an Cygwin environment).
Unfortunately I am not an x86 expert so I am not really able to dig
deeply into it. But what I would recommend is filing an official gcc
bug report and then pinging the x86 gcc maintainers to see if you can
persuade them that it is a problem worth investigating.
If that fails, please could you ping me directly and I will try to
have a go at fixing the problem myself. No promises on solving it
though... :-)
Cheers
Nick
[1]: https://gcc.gnu.org/ml/gcc/2013-05/msg00214.html