[PATCH] D26438: [Verifier] Add verification for TBAA metadata

[Manman Ren via llvm-commits]

manmanren added a comment.

In https://reviews.llvm.org/D26438#591227, @sanjoy wrote:

> In https://reviews.llvm.org/D26438#591194, @mehdi_amini wrote:
>
> > When did we stop using the "old" form? We don't need to preserve an auto-upgrade forever, as long as we can simply drop metadata for old bitcodes this is as valid alternative.
>
>
> We've had the auto upgrade logic for what looks like approximately 3 years.  I think it is reasonable to deprecate the functionality and eventually remove it, though I know (from off-list emails) that it will break (in terms of performance, not correctness) downstream users.


Can you explain more on why it will break downstream users in terms of performance?

Cheers,
Manman

> However, I'm trying to point that, given what I understand so far, we're miscompiling programs //today//.  This makes me wonder if I'm missing something.




https://reviews.llvm.org/D26438