[llvm] [LoongArch] Optimize inserting extracted elements (PR #146018)

[via llvm-commits]

zhaoqi5 wrote:

> Use this patch to support extract i8/i16 type element from hi128 part of 256bit vector. Please update tests too. [support-extract-i8-i16-type-element-from-hi128-part.txt](https://github.com/user-attachments/files/21014880/support-extract-i8-i16-type-element-from-hi128-part.txt)

Done. Thanks for your efforts on this.

https://github.com/llvm/llvm-project/pull/146018