Updated the diff for the new revision, refactored naming functions, accepted suggestions by lebedev.
Thank you for the review! @lebedev.ri
Is the code ready for the mainline?

Gentle ping ;)

In D66029#1639228, @hfinkel wrote:

Now the canonicalizer sorts values in PHI nodes. After a discussion, I have decided not to remove duplicates. Those duplicates could come from some other passes and in my opinion, the canonicalizer should make them stand out instead of removing them.

I suppose that you mean that, if passes are introducing duplicates, that's something that we'd rather fix? That might be true. I'm okay with proceeding on this basis. If we need the deduplicating behavior we'll find out.

We have been experimenting with various ways of reordering output instructions hoping to add it now, but it looks to be much tougher than we thought. We hope to add it in a next commit.

• PHI node canonicalization
• Tests
• Release notes
• Docs

I would like to thank everyone for your valuable feedback! I have fixed the code and moved the pass to lib/Tranfroms/Utils. I hope I have correctly integrated the pass with the rest of the LLVM (we should have some checklist for that).

First of all, thank you for your valuable feedback!