[llvm] [LoopUnroll][NFC] Record conditional latch info (PR #182403)

[Joel E. Denny via llvm-commits]

jdenny-ornl wrote:

> oh - could it have a test then that the data is gathered correctly?

That's impossible without further code changes because the new data is not yet used and so doesn't impact output.

> or should it be part of the next PR?

The testing is part of the next PR because only then are there functional changes. 

> IIUC a NFC should be something like a refactoring.

NFC = No Functional Change, and that describes this patch. One of the general purposes of the tag is to indicate testing is impossible, as in this patch.  So this patch is something *like* refactoring. 

I could drop the tag, but then that would lose the helpful point that testing is impossible because there are no functional changes. 

I could squash this patch into the next, but I separated them so there are smaller chunks to review.

https://github.com/llvm/llvm-project/pull/182403