[llvm] StructurizeCFG: Optimize phi insertion during ssa reconstruction (PR #101301)

[Sameer Sahasrabuddhe via llvm-commits]

ssahasra wrote:

I have not yet looked at the code. But looking at the description, is this something that can be used in `CreateControlFlowHub()` as well?

https://github.com/llvm/llvm-project/pull/101301