[llvm] [LLVM][AMDGPU] AMDGPUInstCombineIntrinsic for *lane intrinsics (PR #99878)

[Sameer Sahasrabuddhe via llvm-commits]

ssahasra wrote:

> > Is this PR still active? The general direction looks okay to me, but every place that uses UI needs to show why it is _safe_ to continue using UI after each local change to the code.
> 
> We probably shouldn't be doing this in InstCombine, if we're doing to do this anywhere. It's going to trigger infrequently

@Acim-Maravic are you still working on this? I would like to initiate work on a separate pass. Besides just writing the pass, I think some effort will be spent in evaluating the benefit and figuring out where to run it in the pipeline.

https://github.com/llvm/llvm-project/pull/99878