Getting [GRT-0010] when replacing the MUX4 cell with MUX2s #202
Description
We are currently trying to support a closed source PDK in the DFFRAM compiler. This PDK does not have a MUX4, so we therefore compose it out of three MUX2. We get the error that the cells inside the MUX4 (the MUX2's) are not placed. We were able to recreate this with the SKY130 PDK so it can also be reproduced. Please see this branch to recreate the issue. Note: the issue only happens if certain sizes are generated, like e.g. 128x32 and 256x32. 32x32 works (for the closed PDK, it fails at 32x32, but works at e.g. 8x32). Is this something that is expected, is it a bug or did we do something wrong on our end?
Another thing that might be interesting:
We use the LibreLane v3.0.0.dev44 for our PDK port and since we used the new version of flow variables which seem to be unsupported there, we also had use this version for the DFFRAM compiler. Depending on the LibreLane version, we either get the error in STA (for v2.4.5), or in Global Routing (for v3.0.0.dev44).
Please let us know if there is any more information we should provide!