Use auto profiler to set branch weights

[Diego Novillo]

On Tue, Oct 29, 2013 at 6:02 PM, Chandler Carruth <chandlerc at google.com> wrote:
> I would *vastly* prefer to review this in Phabricator. I'm just too slow
> with patch files.

http://llvm-reviews.chandlerc.com/D2058