This blog provides some really interesting insight into what goes on in testing Visual C++. I'm looking forward to seeing where they go with this.
Answers to Comment Questions
Is understanding the inner working of a compiler vital to compiler testing?
I would say so, at least at some level. In a general sense, I would say it's hard to be really successful at testing anything without understanding the domain area of what you are testing. That said, I don't think many folks came to our compiler test teams with a lot of understanding of the inner workings of a compiler, especially the back end. This is something that we pick up from doing the work.