> That you can't compile CUDA to AMD GPUs isn't NVIDIA's fault, it's AMD, for deciding to pursue OpenCL first, then HSA, and now HIP.
Using a branded & under patent concurrent proprietary technology and copying its API for your own implementation is Maddness that will lead you for sure in front of a court.
It seems that even Google understood that the hard way (https://en.wikipedia.org/wiki/Google_v._Oracle_America)