This is a interesting research project at Microsoft: Phoenix is the framework for all upcoming compiler and JITer optimizations for the Microsofts platforms. Their goal is to unify opmizations and execuction imrpovements for both managed (i.e. .NET) and unmanaged (i.e. Win32) code. Conceptually it uses a three stage optimization and code generation process, with the Phoenix C2.EXE C++ back end compiler being the centerpiece:

A very nice effect of this research program is that it will allow developers to come up with their very own development language and still use the platform optimizations provided by Phoenix.

The research development kit can be found here.