[llvm] [CodeGen] Don't allow function alignment less than the target's minimum (PR #90415)

[Doug Wyatt via llvm-commits]

dougsonos wrote:

> Thanks for contributing LLVM! Would you please add test cases to cover your changed lines?

I will work on that. Any pointers on a general testing approach here?

Idea: construct bitcode source files which mimic what Clang generates, then convert them to assembly language (for some particular target...?) and check the alignment directives.

https://github.com/llvm/llvm-project/pull/90415