[llvm] [RISCV] Remove custom instruction selection for VFCVT_RM and friends (PR #72540)

[Craig Topper via llvm-commits]

topperc wrote:

> I'm a bit unclear on the history here. I was surprised to find this code in ISEL lowering at all, but am also surprised once I found it that all the patterns and pseudos seem to already exist. My best guess is that maybe we didn't do all the possible cleanup after introducing the HasRoundMode mechanism?

That is exactly what happened. The ceil/floor/etc lowering is older than the rounding mode pass.

https://github.com/llvm/llvm-project/pull/72540