[cloudhan]

Thoes "existing libraries" does not necessary mean stdc++, but some parallel primitive, and are essential to performance portability. For example, cub for scan and reduction, cutlass for dense linear algebra[1].

> I think the driver ecosystem for Vulkan is rather high-quality

Sorry, I meant OpenGL. At the time of evaluation, the market shared of vulkan on Android deivces is too small and been out of consideration at very early stage. I'd assume the state has changed a lot thereafter.

It is really good to see more projects take a shot on compiling C++ to GPU natively.

[1] cutlass itself is not portable, but the recently added cute is well portable as I evaluated. It provides a unified abstraction for hierarchical layout decomposition along with copy primitive and gemm primitive.