[llvm] [LLVM] Add constant folding for llrint, llrintf, llrintl (PR #154799)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

Why do you need to directly constant fold the libcalls? We have intrinsics for these, which we arguably should just always replace libcalls with 

https://github.com/llvm/llvm-project/pull/154799