If I remember correctly it's not just that AMD has poor support for their consumer cards, their Rocm code doesn't compile to a device agnostic intermediate, so you have to recompile for each chip. New and old Cuda compatible cards (like all Geforce cards) can run your already shipped Cuda code, as long as it doesn't use new and unsupported features. So even if AMD had supported more cards, the development and user experience would be much worse anyway where you have to find out if your specific card is supported.
All RDNA2 GPUs and many Vega GPUs could use the same ISA (modulo bugs). Long ago, there was an assumption made that it was safer to treat each minor revision of the GPU hardware as having its own distinct ISA, so that if a hardware bug were found it could be addressed by the compiler without affecting the code generation for other hardware. In practice, this resulted in all but the flagship GPUs being ignored as libraries only ended up getting built for those GPUs in the official binary releases. And in source releases of the libraries, needlessly specific #ifdefs frequently broke compilation for all but the flagship ISAs.
There was an implicit assumption that just building for more ISAs was no big deal. That assumption was wrong, but the good news is that big improvements to compatibility can be made even for existing hardware just by more thoughtful handling of the GFX ISAs.
If you know what you're doing, it's possible to run ROCm on nearly all AMD GPUs. As I've been packaging the ROCm libraries for Debian, I've been enabling support for more hardware. Most GFX9 and GFX10 AMD GPUs should be supported in packages on Debian Experimental in the upcoming days. That said, it will need extensive testing on a wide variety of hardware before it's ready for general use. And we still have lots more libraries to package before all the apps that people care about will run on Debian.
SYCL is still very early on in development and I don’t see it really picking up until support is up-streamed to the llvm project, at the very least. That said, I am a firm believer in the single source philosophy. There just isn’t a tractable alternative.
