This is a port of the IA32 version and is needed to allow 
changing the register allocator interface in a later change.



Review URL: http://codereview.chromium.org/6250027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6436 ce2b1a6d-e550-0410-aec6-3dcde31c8c00