[llvm] [AArch64] Handle inttoptr+add+ptrtoint pattern in lowerConstantPtrAuth (PR #189474)

[Oliver Hunt via llvm-commits]

ojhunt wrote:

> @rjmccall would you mind looking at the mentioned swift codegen issue? Is that some idiosyncrasy we don't normally generate or is there something important we've missed in upstreaming?

ignore me - I thought this was one of the other PRs (one of the codegen ones), this one is asm printing and I assume we just don't have existing tests

https://github.com/llvm/llvm-project/pull/189474