[PATCH] D30790: [LVI] Add an LVI printer pass to capture test LVI cache after transformations

[Anna Thomas via Phabricator via llvm-commits]

anna added a comment.

In https://reviews.llvm.org/D30790#697519, @apilipenko wrote:

> It's worth noting for others that the motivation for the change is a bug we found in JumpThreading LVI cache invalidation. The bug is easily triggered with our downstream changes, but is difficult to trigger it upstream. We need the printer pass to write an isolated upstream test case for this problem.


Yes, the motivation is the bug :)
It is *easier* to trigger the bug upstream with printer pass after jump-threading. This pass will also help in uncovering/testing any other LVI caching issues or LVI broken invariants. Also, we can easily print the LVI cache within any pass (using LVI)  as `LVI->printLazyValueInfoCache(errs())`.


https://reviews.llvm.org/D30790