[llvm] [SCEV] Try to re-use existing LCSSA phis when expanding SCEVAddRecExpr. (PR #147214)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

Hm, this has no impact in the real world: https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2550.

https://github.com/llvm/llvm-project/pull/147214