[llvm] [TailRecElim] Fix miscompile of returns using a non-eliminated recursive call (PR #214503)

[Federico Bruzzone via llvm-commits]

FedericoBruzzone wrote:

> LG. I don't think it's the case, but, while at it, could you please check if the other original path (assoc/commutative one) has the same issue?

Thanks for the question. No, the original path is not affected by this issue. 

BTW, is your approval enough to get the `TailRecElim` PR merged? 
There is obviously no problem waiting for @efriedma-quic as well :D

https://github.com/llvm/llvm-project/pull/214503