[llvm] [GVN] Support rnflow pattern matching and transform (PR #162259)

[Nikita Popov via llvm-commits]

nikic wrote:

> I feel like I saw a comment somewhere that doing the GVN transform would improve performance slightly, but I have trouble finding it, maybe I imagined it...

Ah, I think it was this one, on the test case PR: https://github.com/llvm/llvm-project/pull/141556#discussion_r2165781518 I guess that one was an estimated number and not a measurement.

https://github.com/llvm/llvm-project/pull/162259