[llvm] [MachineSSAUpdater][AMDGPU] Add faster version of MachineSSAUpdater class. (PR #145722)

[Valery Pykhtin via llvm-commits]

vpykhtin wrote:

> We also use SSAUpdater in AMDGPUGlobalISelDivergenceLowering.cpp, test changes look fine, instructions are added at different time as far as I can see. Why not replace existing one with fast version?

Sure, but let's do it gradually.

https://github.com/llvm/llvm-project/pull/145722