[llvm] [DAGCombine] Improve bswap lowering for machines that support bit rotates (PR #164848)

[via llvm-commits]

AZero13 wrote:

<img width="1043" height="183" alt="Screenshot 2025-10-24 at 12 21 05 PM" src="https://github.com/user-attachments/assets/a1015aa0-f331-4d59-8ab6-3b0f22d24c17" />

Already is folded to bswap...

https://github.com/llvm/llvm-project/pull/164848