[llvm] ISel: introduce vector ISD::LRINT, ISD::LLRINT; custom RISCV lowering (PR #66924)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> Maybe the costs tests at least?

Same issue. The module is broken, and the cost model tests can't work, since the vector versions of [l]lrint haven't yet been introduced.

https://github.com/llvm/llvm-project/pull/66924