"We already have code generators for turning kernels into Com- mon Lisp code and for turning a subset of kernels into C++ or CUDA code. Right now, our strategy is to use C++ and GCC when possible, and Common Lisp code otherwise. In the future, we plan to make the C++ generator obsolete by using SIMD optimized Common Lisp instead. Doing so would build on our previous work on s b - s i m d that we presented at the 15th European Lisp Symposium in Porto"

My take from that is, that for CUDA external tools are used today. Still, interesting work.

What do you mean by external tools?