GRT/STA hit "G matrix is singular" for two asap7 designs

[jeffng-or]

Subject

[Stage]: Global Router.

Describe the bug

When running the RC correlation flow on ASAP7 with MAX_ROUTING_LAYER=M9, two designs (gcd-ccs and swerv-wrapper) run into the following STA error in GRT:

[ERROR STA-1752] G matrix is singular.

In the case of swerv-wrapper, you get a stack:

[ERROR STA-1752] G matrix is singular.
terminate called after throwing an instance of 'std::runtime_error'
  what():  STA-1752
Signal 6 received
Stack trace:
 0# 0x0000000000EFA697 in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
 1# 0x0000000000042520 in /lib/x86_64-linux-gnu/libc.so.6
 2# pthread_kill in /lib/x86_64-linux-gnu/libc.so.6
 3# raise in /lib/x86_64-linux-gnu/libc.so.6
 4# abort in /lib/x86_64-linux-gnu/libc.so.6
 5# 0x00000000000A2B9E in /lib/x86_64-linux-gnu/libstdc++.so.6
 6# 0x00000000000AE20C in /lib/x86_64-linux-gnu/libstdc++.so.6
 7# 0x00000000000AE277 in /lib/x86_64-linux-gnu/libstdc++.so.6
 8# 0x00000000000AE4D8 in /lib/x86_64-linux-gnu/libstdc++.so.6
 9# 0x000000000096C30A in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
10# sta::dbStaReport::errorMsg(int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
11# 0x00000000010D6BBB in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
12# sta::PrimaDelayCalc::primaReduce() in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
13# sta::PrimaDelayCalc::simulate() in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
14# sta::PrimaDelayCalc::gateDelays(std::vector<sta::ArcDcalcArg, std::allocator<sta::ArcDcalcArg> >&, std::map<sta::Pin const*, unsigned long, sta::PinIdLess, std::allocator<std::pair<sta::Pin const* const, unsigned long> > > const&, sta::Scene const*, sta::MinMax const*) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
15# sta::PrimaDelayCalc::gateDelay(sta::Pin const*, sta::TimingArc const*, sta::Delay const&, float, sta::Parasitic const*, std::map<sta::Pin const*, unsigned long, sta::PinIdLess, std::allocator<std::pair<sta::Pin const* const, unsigned long> > > const&, sta::Scene const*, sta::MinMax const*) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
16# sta::GraphDelayCalc::findDriverArcDelays(sta::Vertex*, sta::MultiDrvrNet const*, sta::Edge*, sta::TimingArc const*, sta::Scene const*, sta::MinMax const*, sta::ArcDelayCalc*, std::map<sta::Pin const*, unsigned long, sta::PinIdLess, std::allocator<std::pair<sta::Pin const* const, unsigned long> > >&) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
17# sta::GraphDelayCalc::findDriverEdgeDelays(sta::Vertex*, sta::MultiDrvrNet const*, sta::Edge*, sta::ArcDelayCalc*, std::map<sta::Pin const*, unsigned long, sta::PinIdLess, std::allocator<std::pair<sta::Pin const* const, unsigned long> > >&, std::array<bool, 2ul>&) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
18# sta::GraphDelayCalc::findDriverDelays1(sta::Vertex*, sta::MultiDrvrNet*, sta::ArcDelayCalc*, std::map<sta::Pin const*, unsigned long, sta::PinIdLess, std::allocator<std::pair<sta::Pin const* const, unsigned long> > >&) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
19# sta::GraphDelayCalc::findDriverDelays(sta::Vertex*, sta::ArcDelayCalc*, std::map<sta::Pin const*, unsigned long, sta::PinIdLess, std::allocator<std::pair<sta::Pin const* const, unsigned long> > >&) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
20# sta::GraphDelayCalc::findVertexDelay(sta::Vertex*, sta::ArcDelayCalc*, bool) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
21# 0x00000000011D03E4 in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
22# sta::DispatchQueue::dispatch_thread_handler(unsigned long) in /OpenROAD-flow-scripts/tools/install/OpenROAD/bin/openroad
23# 0x00000000000DC253 in /lib/x86_64-linux-gnu/libstdc++.so.6
24# 0x0000000000094AC3 in /lib/x86_64-linux-gnu/libc.so.6
25# clone in /lib/x86_64-linux-gnu/libc.so.6
Elapsed time: 1:23.68[h:]min:sec. CPU time: user 1083.66 sys 10.34 (1307%). Peak memory: 3967536KB.

The default runs with MAX_ROUTING_LAYER=M7 don't encounter the errors.

Expected Behavior

Successful GRT run

Environment

orfs git commit tag: afad87da8d1ebd6ef1bc94288b4204420975a549

To Reproduce

gcd-ccs tarball: https://drive.google.com/file/d/1wlIEAq_B1YAkglm5aoEqLNkg2DUus21E/view?usp=drive_link
swerv_wrapper tarball: https://drive.google.com/file/d/1Tg5pAKO_2JtV8BfP0E4IH39YGhaKP2Uk/view?usp=drive_link

Relevant log output

Screenshots

No response

Additional Context

No response

[maliberty]

I would guess we are feeding in bad parasitics

[jeffng-or]

True, since this run was using the original setRC.tcl, which doesn't have M8 nor M9 parasitics defined.

[jeffng-or]

FYI. Looks like both gcd-ccs and swerv_wrapper complete successfully with the modified setRC.tcl file.