[llvm] [InstCombine] Reducing rust i128::midpoint instructions (PR #99614)

[Julius Alexandre via llvm-commits]

medievalghoul wrote:

> I am not sure whether it is appropriate to do this transform in InstCombine. It would be better to do this in SDAG.
> 
> 

Ah, I see. Just curious, why would I put this in SDAG rather than InstCombine?

https://github.com/llvm/llvm-project/pull/99614