[clang] [llvm] [SimplifyCFG] Emit SelectInst when folding branches to common dest with different PHI incoming values (PR #144434)

[David Sherwood via llvm-commits]

david-arm wrote:

I tried this out with SPEC2017 on a neoverse-v2 machine and it causes a 6.4% regression in mcf, so it's still not great to be honest.

https://github.com/llvm/llvm-project/pull/144434