@aeubanks I believe this is ready for review/merge. Can you please look into this?
Personally I don't see any obvious things that might require immediate work from my end.

In D137103#4008551, @aeubanks wrote:

also this current patch doesn't apply cleanly on main

In D137103#4008550, @aeubanks wrote:

can you provide the configuration you're using and the list of test failures? I'm not seeing any test failures aside from two pass manager pipeline failures with -DLLVM_EXAMPLEIRTRANSFORMS_LINK_INTO_TOOLS=ON which don't really matter

Sorry, completely forgot about this diff. Got distracted with other tasks.
I spent some time to figure out why it is not passing on my end and still 5 tests are failing, but frankly speaking - no clue. My best guess is that I might have missed some option in building, or some configuration with my machine is just causing those failures.

Sorry, work has been postponed on this task, due to some other more important issues.
I'm planning to have some updates to this diff by end of this week.

I still need to do some more debugging because with current patch following tests started to fail:

Thanks @aeubanks for review. I should provide update this week.

Addressed (hopefully) all review comments.
I tried to understand how the naming schemas should work for registering new pass plugin, but there is a chance I might have missed something or misunderstood.
Bottom-line question is, what should I change, so I can call this pass with flags -tut-simplifycfg -tut-simplifycfg-version=XX?

This is currently WIP patch, because I have some issues in understanding how exactly the porting should happen. I've been following @aeubanks recommendation from discourse, but two main things that I found unclear so far are:

Sorry, I didn't realize that update means completely new diff rather than merging with previous changes. This is merge of my 2 previous patches.

Removed tests that can be safely removed based on previous comments.

There are still few tests left with which I'm not sure what resolution would be the best. Any comments are highly appreciated.

In D134150#3799849, @aeubanks wrote:

lg, thanks!
I can push for you if you don't have permissions

@RKSimon could you please merge this diff? I don't have required permissions to do so. Thanks!

@RKSimon could you please merge this diff? I don't have required permissions to do so. Thanks!

Refactor of Functions added in D125831.

Following @RKSimon suggestion I've split diff on two separate diffs.