[llvm] [AMDGPU][TTI] Add Target Hook for Instruction Uniformity (getInstructionUniformity) (PR #137639)

[Pankaj Dwivedi via llvm-commits]

PankajDwivedi-25 wrote:

I can see the target intrinsic of this hook is currently classified as `sourceOfDivergence` in .td file, which is hence marked divergent during the initialization phase itself of the uniformity analysis.

For example, I have removed one such intrinsic from the list in the .td, and now the hook can classify it as uniform if one or more of its operands are uniform.

https://github.com/llvm/llvm-project/pull/137639