[clang] [llvm] [AMDGPU] Adding the amdgpu-num-work-groups function attribute (PR #79035)

[Krzysztof Drewniak via llvm-commits]

krzysz00 wrote:

The main case I had in mind when adding the annotation was `range()`-like information: that is, the ability to infer `nsw` and friends on workgroup IDs and dimensions

https://github.com/llvm/llvm-project/pull/79035