Dang. I wish someone here was qualified to argue with Cheese
Why isn't Dr. Ian here? Why does he hate the forums for intellectual discourse?
The closest thing you might get is this Bolt GPU for path tracing, but:
#1. It's using (AFAICT) proprietary extensions to RISC-V.
#2. It almost certainly sucks at CPU tasks.
Having a CPU ISA and being able to run CPU tasks is not the same thing.
As Cheese commented CPUs and GPUs fulfill fundamentally different compute roles.
CPUs are largely task oriented, with parallel data processing as an afterthought provided by wide SIMD ALUs in the modern day.
GPUs are wide/parallel from the ground up and data throughput oriented.
There are reasons that processor design is switching back to accelerators with separate design and silicon manufacturing.
#1. Separating dies allows for process node tuning to each function (chiplets supreme).
#2. A jack of all trades design is never going to fly in a world where we all want perf/watt to win simply so that the planet doesn't melt.
Maybe if Vaire Computing's so called "reversible logic" works out such concepts might get revisited - but at the end of the day it's still going to be suboptimal.