[llvm] [Instructions] cache computed shufflevector properties (PR #115536)

[Princeton Ferro via llvm-commits]

Prince781 wrote:

Hi all,

Updated the PR to merge shufflevector attribute analyses into a single pass over the mask. I've left other users (like BasicTTIImpl) alone for now, as I don't have a real-world example to motivate changing them.

https://github.com/llvm/llvm-project/pull/115536