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

[Nikita Popov via llvm-commits]

nikic wrote:

> > Compile-time: http://llvm-compile-time-tracker.com/compare.php?from=a7fb25dd1fcc2e5afcc65cccfa83b7b381b48906&to=18cda5b39d709a861cea69e690d674c4b49789b4&stat=instructions:u
> 
> I wonder if the slow down is due to running CycleAnalysis, and whether we could somehow avoid that on targets that don't care about divergence.

Very likely. And yes, you should be able to easily avoid that in the new pass manager by delaying the analysis fetch until after the hasBranchDivergence() check.

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