[llvm] RISC-V: Support vectorizing FMINIMUMNUM and FMAXIMUMNUM (PR #135727)

[Pengcheng Wang via llvm-commits]

https://github.com/wangpc-pp commented:

The CodeGen is OK, but I think we need more tests (I think you just need to reorganize the structure):
1. `@llvm.maximumnum`/`@llvm.minimumnum` with scalable vector types.
2. `@llvm.maximumnum`/`@llvm.minimumnum` with fixed vector types.

And also the VP intrinsics version (if exists). Each is in a standalone file.

https://github.com/llvm/llvm-project/pull/135727