[se6]

> Thus OpenCL seems ultimately more proprietary than CUDA,

Could not be further from the truth there! OpenCL is an open standard, can be used to program GPU, CPU and even FPGA. It is definitively NOT proprietary in any sense! To target both AMD and NVidia GPU, you do not need any vendor specific flag at all. Yes, OpenCL, is like OpenGL pretty verbose and explicit. It can be a bit tedious but once you've factored this verbosity in a framework of some kind, it becomes pretty easy to use.

HIP seems interesting, but I am unwilling to invest on it yet. What will happen if for whatever reason AMD abandon it in 6 months? No such worries with OpenCL.

[pjmlp]

OpenCL just like its graphics cousin, is full of extensions leading to multiple code paths, if one wants to take advantage of GPU features.

Also AFAIK there isn't any vendor supporting OpenCL 2.1, which means we are forced to use C or languages with compilers that are able to target C. Including the whole dance of loading, compiling and linking at runtime.

If AMD decides to go HIP only, and given that no mobile OS cares about OpenCL support, then those worries apply to it as well.