[llvm] [IR] Add support for runtime mask within `llvm.shufflevector` intrinsic (PR #208872)

[Oscar Smith via llvm-commits]

oscardssmith wrote:

Since yesterday, I have not undread these policies.

> Please reply to this message to confirm that you have read these policies, especially the LLVM AI Tool Use Policy, and that any AI tool usage has been noted in the PR description.



https://github.com/llvm/llvm-project/pull/208872