[llvm] [TailDuplication] recalculate NoPhis after pass (PR #211913)

[Matt Arsenault via llvm-commits]

arsenm wrote:

These exist for pass pipeline debugging and enforcing rules when manually running MIR. They don't have real meaning or use within the pipeline, and should not have cycles spent trying to keep them dynamically accurate. If the pass can ever introduce a phi, it should be cleared. You should be fixing this somewhere else 

https://github.com/llvm/llvm-project/pull/211913