@User @User How bad is it if macros are not a multiple of SITE? I see the location of tap cells shifting around this macro. Is this just a bit ugly, or a more critical problem?

Sorry, not qualified to answer.

I don't think it is a big deal. The tap cells will always shift around a macro

In my MPW1 project this "trailing edge skew" ended up causing a design rule violation at the right edge of the chip (in the transition there was a slightly too long region without a tap cell). Normally, however, it is just ugly and you don't have to worry about it. I showed the skew problem in the middle of the readme for my project: https://github.com/fiberhood/MorphleLogic

@User @User Thanks!

@User Nice writeup! @User looks like any problems created will be caught by final DRC. However, would be nice if the placer was intelligent enough to realize that beforehand. @User Is that something OR calculates?

It sounds like a bug as there should never be a violation after tapcell insertion

@User it was very bad luck in the first place - slightly moving the macros would change the result. It would take some effort to update the design for a newer version of the tools and the result would be inconclusive. I agree that it was a bug caused by a subtle interaction of the various rules, all of which are more than reasonable. Note that the violation didn't really matter - that corner of the chip had nothing but decoupling capacitors and so would work fine even if the taps were several times further away. So I thought it wasn't worth the effort to try to fix it.