This is looking pretty good, from the libstdc++ side. This latest round of gcc hacking fixes the previous testsuite fixes, so once you get the gcc bits OK'd by Jason you can check in.
> I'd still like to see some testcases for the intrinsic, independent > of the library. Seems like some simple test case along the lines of gcc/testsuite/g++.dg/ext/is_base_of.C will suffice. -benjamin
