[PATCH] D28490: [LV] Don't panic when encountering the IV of an outer loop.

[Michael Kuperstein via Phabricator via llvm-commits]

mkuper added a comment.

In https://reviews.llvm.org/D28490#640629, @sanjoy wrote:

> I can't really review the code; but, did you consider writing the test case in C++ (inside unittests/)?  Relying on LICM to create just the right preconditions seems somewhat fragile (that is, it is possible that a future change to LICM will make this test a no-op).


I agree, it's fragile, but I think it would be really nice to keep this kind of test-case in IR, for the sake of maintainability.
This whole "LV requires LCSSA and LoopSimplify" issue will need to be solved as part of the move to the new pass manager. I'd prefer to leave a FIXME in the test, and set myself a reminder to actually go and fix it in a couple of months. :-)

(Actually, maybe I can avoid this whole thing by running the test with the new pass manager instead of the old one! I'll give it a shot.)


https://reviews.llvm.org/D28490