[llvm] [GlobalISel] Fold instructions with fully-known bits to a constant. (PR #224254)

[Yaxun Liu via llvm-commits]

yxsamliu wrote:

Thanks for the link. I don’t see #198808 folding a fully known result to a constant yet. Could this change build on that work while keeping the cases covered here? If it needs to stay separate, could you explain why?

https://github.com/llvm/llvm-project/pull/224254