[llvm] [SDAG] Add missing float type legalizations for FMODF (PR #128055)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm requested changes to this pull request.

There should be no CHAIN_BARRIER machineinstrs. This is missing necessary support code for it, but it should not be necessary. The chain is a pure DAG concept. I haven't considered the DAG CHAIN_BARRIER yet 

https://github.com/llvm/llvm-project/pull/128055