[llvm] [LangRef] Do not make align imply dereferenceability (PR #158062)

[Nuno Lopes via llvm-commits]

nunoplopes wrote:

My concern with this is that we don't have a way to specify when the IR semantics changes. If someone runs codegenprepare and then takes that IR and reoptimizes it, bad things can happen if we have different semantics for different compiler phases.

While I'm favorable of this particular change because it makes the semantics more tight and doesn't require an artificial increase of object sizes, I do think it's not sufficient to fix the issue. Maybe we can have a module attribute that indicates that accesses and objects have their size round up?

https://github.com/llvm/llvm-project/pull/158062