PDN generates wires with minimum area violation

[eder-matheus]

Describe the bug

In gf12/bp_single, we have a bunch of minimum area violations in Power/Ground nets in the sixth metal layer.

Expected Behavior

PDN nets should not have minimum area violations.

Environment

Git commit: ec214a37b6cfc14ded1e455c48239c8938793df1
kernel: Linux 3.10.0-1160.45.1.el7.x86_64
os: CentOS Linux 7 (Core)
cmake version 3.24.2
-- The CXX compiler identification is GNU 8.3.1
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /opt/rh/devtoolset-8/root/usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- OpenROAD version: v2.0-11553-gec214a37b
-- System name: Linux
-- Compiler: GNU 8.3.1
-- Build type: RELEASE
-- Install prefix: /usr/local
-- C++ Standard: 17
-- C++ Standard Required: ON
-- C++ Extensions: OFF
-- The C compiler identification is GNU 8.3.1
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /opt/rh/devtoolset-8/root/usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Found Python: /opt/rh/rh-python38/root/usr/bin/python3.8 (found version "3.8.13") found components: Interpreter
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Failed
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE
-- Performing Test C_COMPILER_SUPPORTS__-Wall
-- Performing Test C_COMPILER_SUPPORTS__-Wall - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wall
-- Performing Test CXX_COMPILER_SUPPORTS__-Wall - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-array-bounds
-- Performing Test C_COMPILER_SUPPORTS__-Wno-array-bounds - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-array-bounds
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-array-bounds - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-nonnull
-- Performing Test C_COMPILER_SUPPORTS__-Wno-nonnull - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-nonnull
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-nonnull - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-maybe-uninitialized
-- Performing Test C_COMPILER_SUPPORTS__-Wno-maybe-uninitialized - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-maybe-uninitialized
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-maybe-uninitialized - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format-overflow
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format-overflow - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format-overflow
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format-overflow - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-variable
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-variable - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-variable
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-variable - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-function
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-function - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-function
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-function - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-write-strings
-- Performing Test C_COMPILER_SUPPORTS__-Wno-write-strings - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-write-strings
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-write-strings - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-sign-compare
-- Performing Test C_COMPILER_SUPPORTS__-Wno-sign-compare - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-sign-compare
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-sign-compare - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-deprecated
-- Performing Test C_COMPILER_SUPPORTS__-Wno-deprecated - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-deprecated
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-deprecated - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-c++11-narrowing
-- Performing Test C_COMPILER_SUPPORTS__-Wno-c++11-narrowing - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-c++11-narrowing
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-c++11-narrowing - Failed
-- Performing Test C_COMPILER_SUPPORTS__-Wno-register
-- Performing Test C_COMPILER_SUPPORTS__-Wno-register - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-register
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-register - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal
-- Performing Test C_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal - Failed
-- Performing Test C_COMPILER_SUPPORTS__-fpermissive
-- Performing Test C_COMPILER_SUPPORTS__-fpermissive - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-fpermissive
-- Performing Test CXX_COMPILER_SUPPORTS__-fpermissive - Success
-- Performing Test C_COMPILER_SUPPORTS__-x
-- Performing Test C_COMPILER_SUPPORTS__-x - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-x
-- Performing Test CXX_COMPILER_SUPPORTS__-x - Failed
-- Performing Test C_COMPILER_SUPPORTS__c++
-- Performing Test C_COMPILER_SUPPORTS__c++ - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__c++
-- Performing Test CXX_COMPILER_SUPPORTS__c++ - Failed
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-but-set-variable
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-but-set-variable - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-but-set-variable
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-but-set-variable - Success
-- TCL library: /usr/lib64/libtcl.so
-- TCL header: /usr/include/tcl.h
-- TCL readline library: /usr/lib64/libtclreadline.so
-- TCL readline header: /usr/include
-- Found SWIG: /usr/bin/swig (found suitable version "4.1.0", minimum required is "3.0")
-- Using SWIG >= 4.1.0 -flatstaticmethod flag for python
-- Found Boost: /usr/local/lib/cmake/Boost-1.80.0/BoostConfig.cmake (found version "1.80.0")
-- boost: 1.80.0
-- Found Python3: /usr/include/python3.6m (found version "3.6.8") found components: Development Development.Module Development.Embed
-- Found ZLIB: /opt/or-tools/lib64/libz.a (found version "1.2.11")
-- spdlog: 1.8.1
-- Found BISON: /usr/bin/bison (found version "3.0.4")
-- Found Doxygen: /usr/bin/doxygen (found version "1.8.5") found components: doxygen dot
-- STA version: 2.4.0
-- STA git sha: 5b374dd36ad345c9fcd5224e9fc20484393568ab
-- System name: Linux
-- Compiler: GNU 8.3.1
-- Build type: RELEASE
-- Build CXX_FLAGS: -O3 -DNDEBUG
-- Install prefix: /usr/local
-- Found FLEX: /usr/local/bin/flex (found version "2.6.4")
-- TCL library: /usr/lib64/libtcl.so
-- TCL header: /usr/include/tcl.h
-- Check if compiler accepts -pthread
-- Check if compiler accepts -pthread - yes
-- SSTA: 0
-- STA executable: /home/emrmonteiro/OpenROAD/src/sta/app/sta
-- Found re2: /opt/or-tools/lib64/cmake/re2/re2Config.cmake (found version "9.0.0")
-- Found Clp: /opt/or-tools/lib64/cmake/Clp/ClpConfig.cmake (found version "1.17.7")
-- Found Cbc: /opt/or-tools/lib64/cmake/Cbc/CbcConfig.cmake (found version "2.10.7")
-- Found SCIP: /opt/or-tools/lib/cmake/scip/scip-config.cmake (found version "8.0.1")
-- Found OpenMP_CXX: -fopenmp (found version "4.5")
-- Found OpenMP: TRUE (found version "4.5")
-- GPU is not enabled
-- TCL library: /usr/lib64/libtcl.so
-- TCL header: /usr/include/tcl.h
-- Found Eigen3: /opt/or-tools/share/eigen3/cmake/Eigen3Config.cmake (found version "3.4.0")
-- GUI is enabled
-- Charts widget is not enabled
-- Found Boost: /usr/local/lib/cmake/Boost-1.80.0/BoostConfig.cmake (found version "1.80.0") found components: serialization
-- Could NOT find VTune (missing: VTune_LIBRARIES VTune_INCLUDE_DIRS)
-- Found Boost: /usr/local/lib/cmake/Boost-1.80.0/BoostConfig.cmake (found suitable version "1.80.0", minimum required is "1.78")
-- TCL library: /usr/lib64/libtcl.so
-- TCL header: /usr/include/tcl.h
-- Found Boost: /usr/local/lib/cmake/Boost-1.80.0/BoostConfig.cmake (found version "1.80.0") found components: serialization system thread
-- TCL readline enabled
-- Tcl Extended disabled
-- Python3 enabled
-- Configuring done
-- Generating done
-- Build files have been written to: /tmp/tmp.TQcTltHpBU

To Reproduce

The violations are visible in the latest results of our CI.

Relevant log output

No response

Screenshots

No response

Additional Context

No response

[eder-matheus]

@maliberty FYI.

[maliberty]

@gadfort does pdn have a min-area check or patching?

[gadfort]

@maliberty yes, it should for vias and straps. Since there have not been any modifications to pdn I find it strange that this issue would suddenly appear. What changed?

[maliberty]

Its not necessarily new - we are just examining things more closely