[llvm] [GISel][CombinerHelper] Push freeze through non-poison-producing operands (PR #90618)

[Dhruv Chawla via llvm-commits]

dc03-work wrote:

> I would prefer to not touch Util.cpp. We can do that in separate PRs.

TBH I would prefer to do a stacked review but support on GitHub is really bad.

https://github.com/llvm/llvm-project/pull/90618