[llvm] CodeGen: Respect function align attribute if less than preferred alignment. (PR #149444)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

The alignment is queried directly by optimizations through getPointerAlignment; I don't think we can decrease it after the fact.

I'd suggest adding an attribute in the opposite direction; for functions where we don't want the alignment to increase, add a function attribute "minimize-alignment", and the backend won't increase alignment for those functions.

https://github.com/llvm/llvm-project/pull/149444