What leads me to this thought is that even the MS C++AMP blogs have been silent for about a year. Looking at the C++ AMP algorithms library http://ampalgorithms.codeplex.com/wikipage/history it seems nothing at all has happened for over a year.
I used to work on the C++AMP algorithms library. After the initial release, which Microsoft put together I built a number of additional features and ported it to newer versions of VS. It seemed like there was a loss of momentum around C++AMP. I have no plans to do further work on the project.
Make of this what you will. Perhaps someone from Microsoft can clarify things?