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

[Nikita Popov via llvm-commits]

nikic wrote:

Do I understand correctly that you are operating under a model where pointers (specifically int2ptr pointers) may have multiple provenances, but memory accesses can only work on a single object?

My expectation would be that either:

 * A pointer can only have at most one provenance (I have always assumed that this is the case...)
 * A pointer can have multiple provenances, but in that case memory accesses should be defined as requiring the pointer as having provenance for all accessed objects. Not to only access one object.

If it's not one of those options, then even without this LangRef change, you can't do under-aligned load/store widening, which is something we also so.

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