Which AMD cards though? It's one thing to be able to buy AMD hardware for your data center or workstations, but as far as I can see their latest consumer platform RDNA2 doesn't support ROCm [0]. Radeon DNA doesn't support Radeon Open Compute. ROCm have never supported Windows, and it doesn't look like there are any future plans for it either. And when looking at which AMD cards support SPIR or SPIR-V I can't find any good list, but I do find issues where AMD removed support in the drivers and told people to use old drivers if they needed it [1]. Compare to Nvidia where you can use any Geforce card you can find, so if you have a Nvidia GPU you know Cuda will work.
If you control your own hardware and software stack maybe an AMD CDNA card is fine, but if you want to ship software to end users it seems to be difficult to even know what will work. So you use cross platform code for a worse experience on Nvidia and spotty support on AMD, or only Cuda and accept that it's Nvidia only but will give you a better experience.
I haven't done a lot of GPGPU programming, but I've tried to look at it from time to time, and I've been disheartened by it every time. Nvidia's handling of OpenCL, AMD's disregard for SPIR. This is what an AMD representative had to say in 2019 [2]:
"For intermediate language, we are currently focusing on direct-to-ISA compilation w/o an intervening IR - it's just LLVMIR to GCN ISA. [...] Future work could include SPIRV support if we address other markets but not currently in the plans."
If you control your own hardware and software stack maybe an AMD CDNA card is fine, but if you want to ship software to end users it seems to be difficult to even know what will work. So you use cross platform code for a worse experience on Nvidia and spotty support on AMD, or only Cuda and accept that it's Nvidia only but will give you a better experience.
I haven't done a lot of GPGPU programming, but I've tried to look at it from time to time, and I've been disheartened by it every time. Nvidia's handling of OpenCL, AMD's disregard for SPIR. This is what an AMD representative had to say in 2019 [2]:
"For intermediate language, we are currently focusing on direct-to-ISA compilation w/o an intervening IR - it's just LLVMIR to GCN ISA. [...] Future work could include SPIRV support if we address other markets but not currently in the plans."
[0] https://github.com/RadeonOpenCompute/ROCm/issues/1180#issuec...
[1] https://community.amd.com/t5/opencl/spir-support-in-new-driv...
[2] https://github.com/RadeonOpenCompute/ROCm-OpenCL-Runtime/iss...