[llvm] [AMDGPU][GlobalISel] Enable kernel argument preloading (PR #134655)

[Tim Gymnich via llvm-commits]

tgymnich wrote:

> > @arsenm do we want to skip kern arg preloading if the argument is not used? This kind of makes the tests in their current form a bit pointless.
> 
> I'm pretty sure you you need to preload a consecutive block, so you need to preload unused arguments if it is in the middle of other useful arguments to preload

Is there any documentation about the hardware and ABI besides the SDAG implementation?

https://github.com/llvm/llvm-project/pull/134655