Powerswitch floorplanning and placement issues

[kareefardi]

Describe the bug

I am unable to insert power switches using UPF without causing overlaps. I am using the power switch abstract view that is present in the test cases of OpenROAD (with slightly modified signal pins). Here is what I have tried.

Scenario 1:

• Power switch with single height site
• Tapcells overlap power switches
• Standard cells overlaps power switches

Scenario 2:

• Power switch cell with double height site in floorplan
• PDN places overlapping power swtiches
• Tapcells overlaps power switches

To me the logical scenario is scenario 2 as the power switch cell is a double height cell. However it seems like whenever passing -additional_sites unithddbl to initialize_floorplan, Pdngen inserts switches on both rows (the double height row and the single height row)?

Expected Behavior

Be able to properly insert power switch cells without overlaps

Environment

Git commit: e956dce5da5e738a5c0d9fa0b097b51f4798cd18
kernel: Linux 6.5.0-35-generic
os: Ubuntu 22.04.3 LTS (Jammy Jellyfish)
cmake version 3.25.1
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-- OpenROAD version: v2.0-14288-ge956dce5d
-- System name: Linux
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-- Build type: RELEASE
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-- boost: 1.81.0
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-- STA version: 2.5.0
-- STA git sha: ee21333caa14eac641bcccbf2a36b4f6b4ba7de1
-- System name: Linux
-- Compiler: GNU 11.4.0
-- Build type: RELEASE
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-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- SSTA: 0
-- Found SWIG: /usr/bin/swig4.0 (found suitable version "4.0.2", minimum required is "3.0")  
-- STA executable: /home/karim/work/OpenROAD/src/sta/app/sta
-- Found re2: /home/karim/Downloads/or-tools_x86_64_Ubuntu-22.10_cpp_v9.5.2237/lib/cmake/re2/re2Config.cmake (found version "9.0.0") 
-- Found Clp: /home/karim/Downloads/or-tools_x86_64_Ubuntu-22.10_cpp_v9.5.2237/lib/cmake/Clp/ClpConfig.cmake (found version "1.17.7") 
-- Found Cbc: /home/karim/Downloads/or-tools_x86_64_Ubuntu-22.10_cpp_v9.5.2237/lib/cmake/Cbc/CbcConfig.cmake (found version "2.10.7") 
-- Found SCIP: /home/karim/Downloads/or-tools_x86_64_Ubuntu-22.10_cpp_v9.5.2237/lib/cmake/scip/scip-config.cmake (found version "8.0.1") 
-- Found OpenMP_CXX: -fopenmp (found version "4.5") 
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-- Found Boost: /usr/local/lib/cmake/Boost-1.81.0/BoostConfig.cmake (Number of processor cores: 20
found suitable version "1.81.0", minimum required is "1.78")  
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
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-- Found Eigen3: /usr/share/eigen3/cmake/Eigen3Config.cmake (found version "3.4.0") 
-- TCL readline enabled
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-- Python3 enabled
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To Reproduce

powerswitch.zip

Inside the zip file, script.tcl for the first scenario and script2.tcl for the second scenario.

Relevant log output

No response

Screenshots

Scenario 1: Scenario 2:

Additional Context

No response

[maliberty]

@gadfort any thoughts?

[gadfort]

@maliberty I think the double height rows were added after this code, so don't think PDN checks (I can fix that). I'll need to spend some time to figure out why the tapcells are getting ignored by PDN (it should be honoring them, but I'm not sure what happens if no legal site can be found).