CTS/RSZ - missing gate clonning

[gudeh]

Describe the bug

Issue happens when using DPL negotiation legalizer with two designs. It was observed on the metrics update in this PR .

Big TNS degradation during CTS for asap7/ibex and finish TNS for asap7/riscv32i-mock-sram:

- ibex (asap7)                cts__timing__setup__tns          740.49%  (-1630.0 → -13700.0)
- riscv32i-mock-sram (asap7)  finish__timing__setup__tns       346.31%  (-298.0 → -1330.0)

During CTS on asap7/ibex with master we have some paths with positive slack that turned into negative when using negotiation legalizer:

master by the left:

Comparing a path that goes from positive to negative I noticed at least one net that didn't went through gate cloning. On master it goes from 30 fanouts to 16, while on negotiation it stays with 30 fanouts. I suspect this is the cause of the high TNS degradation.

The net divided in two at master:

The net with 30 fanouts with negotiation:
the instance driving the blue net is called clone5238, and the instance driving the green net is called place4577

I also compared the full logs and I don't see any big differences. The paths themselves are extremely similar looking at the gui. Makes me think the missing gate cloning for place4577 is likely the cause of the TNS degradation. Although I don't have an explanation to why the gate cloning was not performed.

Expected Behavior

Reasonable TNS when using negotiation, or at least the missing gate cloning to be performed as it used to on master.

Environment

Error: Access to the public repository 'The-OpenROAD-Project/OpenROAD' is restricted.
Please use the private repositories for your work.

To Reproduce

secure-CI ran at: https://jenkins.openroad.tools/job/OpenROAD-flow-scripts-Public/job/PR-4186-merge/23/display/redirect

Relevant log output

Screenshots

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Additional Context

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