[llvm] [DAG] Teach SelectionDAGBuilder to read parameter alignment of compressstore/expandload. (PR #83763)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

It's probably worth documenting the behavior in LangRef, like we do for other intrinsics that support "align" markings.

https://github.com/llvm/llvm-project/pull/83763