[llvm] [DebugInfo][LoopIdiomRecognize] Fix #82582: Wrong debug location update in processLoopStridedStore (PR #82723)

[Orlando Cazalet-Hyams via llvm-commits]

https://github.com/OCHyams commented:

Hi @Apochens - sorry, I missed this one when you were originally submitting these. Are you still able to work on this patch?

According to [the docs](https://llvm.org/docs/HowToUpdateDebugInfo.html#when-to-preserve-an-instruction-location) this change looks right:

> **When to preserve an instruction**
> ...
> Examples of transformations for which this rule does not apply include:
> * LICM. E.g., if an instruction is moved from the loop body to the preheader, the rule for dropping locations applies.

I think this is an older PR, so the test has a few nits that need fixing up. Then LGTM.

https://github.com/llvm/llvm-project/pull/82723