grt: add incremental routing support to CUGR#9679
grt: add incremental routing support to CUGR#9679sparsh-karna wants to merge 7 commits intoThe-OpenROAD-Project:masterfrom
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Add addDirtyNet(), startIncremental(), and endIncremental() methods to support incremental global routing in the CUGR engine, along with dirty_net_indices_ and incremental_mode_ state tracking. Signed-off-by: TheUnnamedOne-design <aditya07.11.04.12@gmail.com> Signed-off-by: Sparsh Karna <sparsh2005karna@gmail.com>
Signed-off-by: TheUnnamedOne-design <aditya07.11.04.12@gmail.com> Signed-off-by: Sparsh Karna <sparsh2005karna@gmail.com>
Signed-off-by: Sparsh Karna <sparsh2005karna@gmail.com>
Signed-off-by: Sparsh Karna <sparsh2005karna@gmail.com>
Signed-off-by: Sparsh Karna <sparsh2005karna@gmail.com>
Signed-off-by: Sparsh Karna <sparsh2005karna@gmail.com>
…rtion When repair_timing inserts a buffer, a net is split into two. The previous incremental flow rerouted the stale GRNet objects from init() — pin list, access points, and bounding box all predated the insertion. Implement Design::updateNet() and CUGR::updateNet() to refresh per-net CUGRNet/GRNet state from the database before rerouting. Wire into endIncremental() and expose as grt::update_net Tcl command. Also add null guard in GridGraph::commitTree() for freshly rebuilt nets and a regression test exercising the full incremental update path. Signed-off-by: Sparsh Karna <sparsh2005karna@gmail.com>
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Code Review
This pull request adds incremental global routing support to the CUGR backend, mirroring the existing FastRoute API. The changes are well-structured, introducing new logic for CUGR within GlobalRouter and implementing the core incremental functionality in the cugr component. The addition of a test case for net topology updates is also a good validation of the new feature. The suggestions to improve performance and code clarity remain valid.
Note: Security Review did not run due to the size of the PR.
| for (const int idx : dirty_net_indices_) { | ||
| updateNet(gr_nets_[idx]->getDbNet()); | ||
| } |
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This loop iterates over dirty_net_indices_ to refresh net data before rerouting. While this is safe for std::set as iterators are not invalidated on insertion, it can be confusing. Iterating over the nets_to_route vector, which is a copy of the dirty nets at the beginning of the function, would be clearer and more robust against future changes. This ensures you are iterating over a fixed set of nets.
for (const int idx : nets_to_route) {
updateNet(gr_nets_[idx]->getDbNet());
}| for (CUGRNet& net : nets_) { | ||
| if (net.getDbNet() == db_net) { | ||
| net.setPins(std::move(pins)); | ||
| net.setLayerRange(layer_range); | ||
| return; | ||
| } | ||
| } |
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This loop performs a linear scan over all nets to find the one to update. This can be inefficient if there is a large number of nets, leading to O(N) complexity for each update. To improve performance, consider using a map (e.g., std::unordered_map<odb::dbNet*, int>) to store the mapping from dbNet* to its index in the nets_ vector. This map could be populated in readNetlist and maintained in updateNet, allowing for an average O(1) lookup.
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Adds incremental global routing support to the CUGR backend, mirroring the
existing FastRoute incremental API.
Changes
addDirtyNet()to mark nets needing reroutestartIncremental()/endIncremental()to CUGR state machineReopens #9645 (accidentally closed during branch cleanup).