> GPU instructions sets change every year/generation.

1. It's every two-to-three years.

2. It's not like they change into something completely different.

3. PTX is not a hardware instruction set, it's just an LLVM IR variant

4. I don't need to only target an instruction set directly, but it does help to know what instructions the hardware actually executes. And this is just like for CPUs (ok, not just like, because CPUs have u-ops, and I don't know that GPUs have those).