Now that the NVPTX back-end has been integrated into ToT and already surpasses the PTX back-end in terms of functionality, I plan to remove the PTX back-end from the LLVM tree soon. The only change that users will need to be aware of are the address space mapping (please see lib/Target/NVPTX/NVPTX.h for the new mappings). The old intrinsics will remain valid for the new NVPTX back-end.
What I would like to know is if anyone is against removing this back-end. The sources will still be available in LLVM history, including the LLVM 3.1 release, but going forward I plan to only maintain the NVPTX sources.
If I do not hear any objections by the end of the week, I will probably remove it this week-end.