This change split a restore point to allow it to only post-dominate blocks reachable by use or def of CSRs/FI.
This is a WIP and I'm posting it to continue the discussion about :
Bugzilla : https://bugs.llvm.org/show_bug.cgi?id=33868
I will be happy to hear any high level comment/suggestion.
This change itself increase 15% more shrink-wrapping in spec2000/2006/2017 benchmarks. I observed 160% more shrink-wrapping in spec2000/2006/2017 benchmarks if we apply the copy forwarding (D41835), PostRASink (D41463), and this change all together.