[llvm] Reland "[ValueTracking] Compute knownbits from known fp classes" (PR #92084)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Hi @dtcxzyw, one of our internal tests started failing and I bisected it back to this change you made. I have put the repro in #92217, can you take a look?

Thank you! I will have a look :)


https://github.com/llvm/llvm-project/pull/92084