@User, @User: I'm looking at the slowness of netgen in the final stage, which looks like it may be related to property matching instead of symmetry breaking. I'll let you know what I find. I first saw this when running large SoC cores, and I was busy trying to make tapeout, so the fact that it eventually finished meant that I could punt on investigating it. And I've been punting ever since.

let us know if you need the test cases

and thank you for taking a look...