[clang] [llvm] [opt][AMDGPU] Add pass to handle AMDGCN pseudo-intrinsics, start with `llvm.amdgcn.wavefrontsize` (PR #114481)

[Stanislav Mekhanoshin via cfe-commits]

rampitec wrote:

This is really just a constant folding rather than a new pass. If the concern is that InstCombine works too late that is possible to add an earlier invocation.

https://github.com/llvm/llvm-project/pull/114481