pad: add custom comparator for GridGraphEdge set to prevent non-determinism

Signed-off-by: Eder Monteiro <emrmonteiro@precisioninno.com>

Author: eder-matheus

src/pad/src/RDLRouter.cpp

@@ -381,7 +381,7 @@ void RDLRouter::route(const std::vector<odb::dbNet*>& nets)
   makeGraph();
 
   // Determine access points
-  std::unordered_map<odb::Point, std::set<GridGraphEdge>> remove_edges;
+  std::unordered_map<odb::Point, GridGraphEdgeSet> remove_edges;
   for (auto& [net, iterm_targets] : routing_targets_) {
     for (auto& [iterm, targets] : iterm_targets) {
       for (auto& target : targets) {
@@ -797,7 +797,7 @@ static odb::Point getValidGridPoint(
 }
 
 void RDLRouter::cleanupGraphEdges(
-    const std::unordered_map<odb::Point, std::set<GridGraphEdge>>& edges)
+    const std::unordered_map<odb::Point, GridGraphEdgeSet>& edges)
 {
   if (edges.empty()) {
     return;
@@ -824,7 +824,7 @@ void RDLRouter::cleanupGraphEdges(
 
 void RDLRouter::populateTerminalAccessPoints(
     RouteTarget& target,
-    std::unordered_map<odb::Point, std::set<GridGraphEdge>>& edges) const
+    std::unordered_map<odb::Point, GridGraphEdgeSet>& edges) const
 {
   // determine new access point in graph
   std::set<odb::Point> snap_pts;
@@ -1181,10 +1181,9 @@ bool RDLRouter::is45DegreeEdge(const odb::Point& pt0,
   return RDLRoute::is45DegreeEdge(pt0, pt1);
 }
 
-std::set<GridGraphEdge> RDLRouter::getVertexEdges(
-    const GridGraphVertex& vertex) const
+GridGraphEdgeSet RDLRouter::getVertexEdges(const GridGraphVertex& vertex) const
 {
-  std::set<GridGraphEdge> edges;
+  GridGraphEdgeSet edges;
 
   GridGraph::out_edge_iterator oit, oend;
   std::tie(oit, oend) = boost::out_edges(vertex, graph_);
@@ -1203,7 +1202,7 @@ std::set<GridGraphEdge> RDLRouter::getVertexEdges(
 std::vector<RDLRouter::GridEdge> RDLRouter::commitRoute(
     const std::vector<GridGraphVertex>& route)
 {
-  std::set<GridGraphEdge> edges;
+  GridGraphEdgeSet edges;
   for (const auto& v : route) {
     const auto v_edges = getVertexEdges(v);
     edges.insert(v_edges.begin(), v_edges.end());

src/pad/src/RDLRouter.h

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include <algorithm>
 #include <cstdint>
 #include <map>
 #include <memory>
@@ -67,6 +68,24 @@ using GridWeightMap
 using GridGraphVertex = GridGraph::vertex_descriptor;
 using GridGraphEdge = GridGraph::edge_descriptor;
 
+// Order edges by (source, target) vertex indices; the descriptor's default
+// operator< compares a heap pointer, giving build-dependent iteration.
+struct GridGraphEdgeLess
+{
+  bool operator()(const GridGraphEdge& lhs, const GridGraphEdge& rhs) const
+  {
+    const auto lhs_lo = std::min(lhs.m_source, lhs.m_target);
+    const auto lhs_hi = std::max(lhs.m_source, lhs.m_target);
+    const auto rhs_lo = std::min(rhs.m_source, rhs.m_target);
+    const auto rhs_hi = std::max(rhs.m_source, rhs.m_target);
+    if (lhs_lo != rhs_lo) {
+      return lhs_lo < rhs_lo;
+    }
+    return lhs_hi < rhs_hi;
+  }
+};
+using GridGraphEdgeSet = std::set<GridGraphEdge, GridGraphEdgeLess>;
+
 struct RouteTarget
 {
   // center point of the target shape
@@ -213,11 +232,11 @@ class RDLRouter
 
   void populateTerminalAccessPoints(
       RouteTarget& target,
-      std::unordered_map<odb::Point, std::set<GridGraphEdge>>& edges) const;
+      std::unordered_map<odb::Point, GridGraphEdgeSet>& edges) const;
   void cleanupTerminalAccessPoints(odb::dbITerm* iterm,
                                    std::vector<RouteTarget>& targets) const;
   void cleanupGraphEdges(
-      const std::unordered_map<odb::Point, std::set<GridGraphEdge>>& edges);
+      const std::unordered_map<odb::Point, GridGraphEdgeSet>& edges);
   std::set<odb::Point> generateTerminalAccessPoints(const odb::Point& pt,
                                                     bool do_x) const;
   TerminalAccess insertTerminalAccess(const RouteTarget& target,
@@ -227,7 +246,7 @@ class RDLRouter
   odb::PtrMap<odb::dbITerm, std::vector<RouteTarget>> generateRoutingTargets(
       odb::dbNet* net) const;
   odb::dbTechLayer* getOtherLayer(odb::dbTechVia* via) const;
-  std::set<GridGraphEdge> getVertexEdges(const GridGraphVertex& vertex) const;
+  GridGraphEdgeSet getVertexEdges(const GridGraphVertex& vertex) const;
 
   void buildIntialRouteSet();
   int reportFailedRoutes(

src/pad/test/rdl_route_failed.ok

@@ -15,7 +15,7 @@
 [INFO PAD-0037] End of routing iteration 7: 89.5% complete
 [INFO PAD-0037] End of routing iteration 8: 89.0% complete
 [INFO PAD-0037] End of routing iteration 9: 88.8% complete
-[INFO PAD-0037] End of routing iteration 10: 88.8% complete
+[INFO PAD-0037] End of routing iteration 10: 88.4% complete
 [WARNING PAD-0006] Failed to route the following 17 nets:
   DVDD
     BUMP_11_3/PAD -> u_v18_6/DVDD, u_v18_7/DVDD, u_v18_5/DVDD, u_v18_4/DVDD, u_v18_8/DVDD, ... (67 possible terminals)
@@ -27,6 +27,7 @@
     BUMP_15_11/PAD -> u_vzz_15/DVSS, u_vzz_16/DVSS, u_vzz_14/DVSS, u_vzz_13/DVSS, u_vzz_12/DVSS, ... (67 possible terminals)
     BUMP_15_7/PAD -> u_vzz_12/DVSS, u_vzz_13/DVSS, u_vzz_11/DVSS, u_vzz_14/DVSS, u_vzz_10/DVSS, ... (67 possible terminals)
     BUMP_1_9/PAD -> u_vzz_29/DVSS, u_vzz_30/DVSS, u_vzz_28/DVSS, u_vzz_31/DVSS, u_vzz_27/DVSS, ... (67 possible terminals)
+    BUMP_8_15/PAD -> u_vzz_21/DVSS, u_vzz_22/DVSS, u_vzz_20/DVSS, u_vzz_23/DVSS, u_vzz_24/DVSS, ... (67 possible terminals)
   VSS
     BUMP_14_9/PAD -> u_vss_6/VSS, u_vss_5/VSS, u_vss_7/VSS, u_vss_4/VSS, u_vss_8/VSS, ... (33 possible terminals)
     BUMP_16_6/PAD -> u_vss_5/VSS, u_vss_6/VSS, u_vss_4/VSS, u_vss_7/VSS, u_vss_3/VSS, ... (33 possible terminals)