[llvm] [ARM] Port ConditionOptimizer to ARM (PR #151187)

[Hussam Alhassan via llvm-commits]

hussam-alhassan wrote:

I'm happy to review this though I'll need some time. I couple immediate thoughts:
- With the `AArch64ConditionOptimizer` under ongoing development (#185532 and others to follow), I'd hesitate to merge this in right now as they'd diverge immediately. There's more shared logic between the cross and intra-block paths which will come as a couple more PRs 
- From there I'm wondering if it's worth making this pass generic instead. If we worked on abstracting out some of the AArch64-specific code into TII hooks (or maybe there are existing ones that could serve us), then adding arm support could be a somewhat simple addition.

None of this is my call however, and it depends on whether the effort is worth the potential long-term maintainability boost (or if it would just complicate things). I'd be happy to contribute to that, though I'd prefer to hear an Arm team member's thoughts on this.

https://github.com/llvm/llvm-project/pull/151187