[llvm] [NFC][DebugInfo] Deprecate iterator-taking moveBefore and getFirstNonPHI (PR #124290)

[Orlando Cazalet-Hyams via llvm-commits]

https://github.com/OCHyams approved this pull request.

Mostly LGTM, with some questions / suggestions inline

---

> NB: as part of this review, please review the commit message as people are going to git-blame back to it:

I think the first para could be slightly clearer. I propose something like:

The RemoveDIs project [0] makes debug intrinsics obsolete and to support this instruction iterators carry an extra bit of debug information. To maintain debug information accuracy insertion needs to be performed with a BasicBlock::iterator rather than with Instruction pointers, otherwise the extra bit of debug information is lost.

[0] (Include link to the RemoveDIs transition page as well)
[1] Discourse Link



https://github.com/llvm/llvm-project/pull/124290