Noticed this while perusing Debian's tree. I'm not sure if this bug can be triggered in conjunction with any of the binutils versions currently available in portage. Nonetheless, it seems like an obvious candidate for the stable queue. More information at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=341257 and the link for the GIT commit can be found in the URL field of this bug.
Created attachment 75486 [details, diff] ia64-new-assembler-fix.patch Patch lifted from debian's tree (see commit referenced in the URL field of this bug also).
None of the CVS binutils builds (that exhibit this issue) are ~ia64/ia64 KEYWORDed so I think this is a non-issue for us as such, but adding the patch will of course help. Thanks for letting us know anyway :)
Fixed in genpatches-2.6.14-7 (gentoo-sources-2.6.14-r6)