Hi Vijayan and Matt, I will explain my issue with more details, maybe you know how to avoid the issue. I'm implementing STA for asynchronous circuits. In the base case, the combinational loops are conveniently cut in the right places. However, for the hold check, I'm guiding the timing calculation making some generated clocks to follow the whole launch path (we need to make a complete loop to do it), and in this path, I'm passing twice by the same instance and the same timing arc, however, it is not exactly the same clock, but, in the second pass, it is a generated clock derived from the master clock that already passed by this timing arc in the first pass (I hope this explanation is clear for someone reading it). In Primetime, this technique works well, because it is not exactly the same clock passing by the same timing arc twice. However, in OpenSTA, I'm seeing that the tool is arbitrarily cutting the timing arc when the second pass is made, I think, because it is a generated clock derived from a master clock that already passed by this timing arc. Is there any way to make OpenSTA behave like Primetime in a case like this (to detect a combinational loop only if it is the same clock)? I hope my explanations are understandable. Thank you in advance. Best Regards, Rodrigo Iga