[llvm] DAG: Handle lowering unordered compare with inf (PR #100378)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon commented:

@arsenm Are you happy with the legality check workaround to avoid the x87 regression? We could attempt a custom lowering if you'd prefer?

https://github.com/llvm/llvm-project/pull/100378