Thank you for the data. I can now repro the problem. It appears to be caused by [check-in b8ba2f17f938c035](src:/info/b8ba2f17f938c035) which, ironically, was intended to make things run faster, not slower. The change is "safe" in the sense that it still gets the correct answer. But it appears to have lost one optimization as it picked up another. It will probably take a few hours (and some sleep and some strong tea and dark chocolate) to fix this. So it might be a day or two before a solution is on trunk.