I found this introduction to porting CUDA on AMD cards. Is it possible to write this inside Blender for better support of AMD cards?
http://gpuopen.com/hip-to-be-squared-an-introductory-hip-tutorial/
http://developer.amd.com/tools-and-sdks/opencl-zone/opencl-resources/programming-in-opencl/porting-cuda-applications-to-opencl/