[llvm] [AMDGPU] Strengthen preload intrinsics to noundef and nonnull (PR #92801)

[Krzysztof Drewniak via llvm-commits]

krzysz00 wrote:

@arsenm Good to know about the kernarg pointer being potentially null, but also, do you have information about when those cases arise? (I suppose in the case where there are no arguments the kernarg pointer is null, but ... why would someone be accessing the kernarg pointer when there are no arguments there?)

Re the ranges, I was going to either do or file a ticket about updating `AMDGPULowerKernelMetadata` to apply `!range` up in the frontend. And now that I've taken a look around for this new range attribute ... I assume what you're wanting is the conservative, calling-convention-independent upper bound in the intrinsic definition?

https://github.com/llvm/llvm-project/pull/92801