mpl2: avoid groupping macros with empty conn signature

The-OpenROAD-Project / OpenROAD

OpenROAD's unified application implementing an RTL-to-GDS Flow. Documentation at https://openroad.readthedocs.io/en/latest/

https://theopenroadproject.org/

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mpl2: avoid groupping macros with empty conn signature #5255

Closed AcKoucher closed 1 week ago

AcKoucher commented 1 week ago

This is an idea to make it possible for mpl2 to find a valid tiling for the root in cases such as sky130hd/chameleon. For this design, multilevel autoclustering engine generates a cluster with three very big macros that have no connection signature at all. This cluster will be further fine shaped to what we see in the image below .

The existence of this cluster ends up preventing SA from fitting all clusters in the outline later on.

github-actions[bot] commented 1 week ago

clang-tidy review says "All clean, LGTM! :+1:"

AcKoucher commented 1 week ago

Running CI

AcKoucher commented 1 week ago

CI passed.