Hello, Bootstrap is currently broken on x86 targets with binutils 2.20 (from 2009) and older (PR54419) because the rdrand instruction is emitted but that instruction is only supported in binutils 2.21 and later. This means bootstrap is broken on almost all x86_64 machines in the compile farm for example. IMNSHO it is not reasonable to require such a very recent binutils to bootstrap gcc, but in any case the requirement isn't even listed.
Also, on at least powerpc64-unknown-linux-gnu (a primary platform) and sparc64-unknown-linux-gnu and probably others (PR54453). The breakage is caused by drepper's patches at r190783 and r190787. The breakage on powerpc64 is now almost a week old. I've notified the original poster of the patches of the problem via the PR audit trail and here on the mailing list, but there has been no response so far (although new patches were posted since than). As per the development plan (http://gcc.gnu.org/develop.html) I'd like to start the 48hr clock for patch reversion. Ciao! Steven
