[llvm] [SCEV] Add special handling for phi when BranchInst's edge doesn't dominate use in phi (PR #163146)

[Eli Friedman via llvm-commits]

https://github.com/efriedma-quic commented:

Would it make sense to add an InstCombine or something like that for this pattern?

I also have a pending patch that touches this code (#152823), but I guess we'll see which is ready first.

https://github.com/llvm/llvm-project/pull/163146