[llvm] [ARM]: codegen `llvm.roundeven.v*` (PR #141786)

[David Green via llvm-commits]

https://github.com/davemgreen commented:

Can you add test cases to
llvm/test/CodeGen/ARM/fp16-fullfp16.ll
llvm/test/CodeGen/ARM/fp16-promote.ll
llvm/test/CodeGen/Thumb2/float-intrinsics-double.ll
llvm/test/CodeGen/Thumb2/float-intrinsics-float.ll
Just like the existing llvm.nearbyint tests. That should cover the scalar types. MVE I can add separately, it should be relatively simple once you have added the scalars in.

There is also a test in llvm/test/CodeGen/ARM/vrint.ll, but it looks almost useless. It should be testing that `vrintn.f32 s0, s0` gets generated, but that might now stop working. The idea is that either llvm.roundeven and llvm.arm.neon.vrintn both produce a vrintn, or (preferably) the llvm.arm.neon.vrintn is auto-upgraded to roundeven, like the aarch64 patch above.

https://github.com/llvm/llvm-project/pull/141786