ZLUDA is a library written by a hobbyist. The comparison you are looking for is oneAPI. They don't have the messaging down, but Intel is good at software.
We really really tried to use oneAPI, for FPGA, working with intel directly.
Every release would completely change some approach requiring restructuring. The only card with “free” compatibility was discontinued the week after we bought them, and the drivers stopped working on the same OS that oneAPI required.
Constantly encountered showstopper bugs that led us to conclude that nobody outside Intel was using it. Some of them appeared to be live-patched on their Devcloud.
Documentation was - reasonably good. But every few months Intel would move or restructure documentation links such that it was impossible to persistenly store a link to a useful document.
Intel may be good at software - but they are utterly crap at actually maintaining a consistent ecosystem that isn’t painful to try and follow.
