[llvm] [Intrinsics] Add @llvm.dereferenceable intrinsic. (PR #120755)

[Florian Hahn via llvm-commits]

fhahn wrote:

> > Alternatively we could use an assume bundle with a dereferenceable attribute. But as a follow-up I would like to allow non-immediate size arguments, and this may not mesh well with the attribute.
> 
> I don't understand this bit. Using a non-immediate arguments for operand bundle assumes is generally okay.
> 
> I don't think we should introduce a new intrinsic if existing assume infrastructure covers it.

I assumed there might be an issue with customizing the logic to handle the attribute with immediate only in the function arg context and variable arguments in the assume context. But if that won't be an issue I'll do it that way, assuming the general idea seems good.

https://github.com/llvm/llvm-project/pull/120755