[llvm] [IR] Add llvm.sincospi intrinsic (PR #125873)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw commented:

What is the benefit of adding this intrinsic? Do you know which ISA has native support of sincospi?
 

https://github.com/llvm/llvm-project/pull/125873