[llvm] [MachineCSE][AArch64] Coalesce subregister copies behind an opt-in target hook (PR #224593)

[Madhur Amilkanthwar via llvm-commits]

madhur13490 wrote:

> This should not be a target hook. I've been working on making this same change for years at this point, and most of the targets are ready. #208051 is the main blocker for ppc

Well, I believe the PPC blocker is been pending for 2+ months now. Meanwhile, it makes sense to have to this a target hook. Once, the blocker is merged we can enable it unconditionally?


https://github.com/llvm/llvm-project/pull/224593