C++/AMP (https://docs.microsoft.com/en-us/cpp/parallel/amp/cpp-amp-ov...) is something along those lines. I dunno if it strictly satisfies your "intrinsic to the language" requirement - you still have to explicitly request GPU processing by using the appropriate parallel_* algorithms and restrict(amp) - but it's intrinsic in a sense that compiler takes a C++ lambda and compiles it to run on the GPU.

But I don't think that you could reasonably make something that just automatically sends any random routine to the GPU, or at least not efficiently. The processing model is just inherently different.