Most likely, this is an upstream issue, but in case Gentoo gcc maintainers would like to be informed of upstream issues affecting Gentoo users, this is one. There is a warning that appears to be incorrect that GCC 4.1.1 provided by Gentoo Linux gives. See upstream report for details at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28488.
INVALID, as is upstream bug.