If LLVM can target AMD GPUs what exactly prevents AMD and ROCm from supporting all the damn GPUs?

At this point I'm convinced that the real problem with AMD GPUs isn't necessarily the compilers (although they do produce mediocre code) or even the hardware itself, but some crappy C++ driver code that can't handle running graphics and compute at the same time. The datacenter GPUs never had to run graphics in the first place, so they are safe.

In my experience, the compiler, compute drivers, and HIP runtime work fine for all modern AMD GPUs. The only parts of the stack that don't run on all GPUs are the math and AI libraries. And that is mostly because AMD isn't building and testing those libraries for unsupported GPUs. The actual work required to enable functional support was straightforward enough that I ported them myself when packaging the libraries for Debian. Though, I had a lot of help on the testing.

See the Debian Trixie Supported GPU list: https://salsa.debian.org/rocm-team/community/team-project/-/...