[llvm] [AMDGPU] AMDGPUIGroupLP: Avoid repeating reachability checks in greedy algorithm (PR #182463)

[Frederik Harwath via llvm-commits]

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@@ -729,21 +733,38 @@ void PipelineSolver::greedyFind(
       LLVM_DEBUG(dbgs() << "SGID # " << CandSGID << " has conflicting rule\n");
       continue;
     }
-    TempCost = addEdges(SyncPipeline, CurrSU.first, CandSGID, AddedEdges);
+
+    std::list<std::pair<SUnit *, SUnit *>> TempEdges;
+    TempCost = addEdges(SyncPipeline, CurrSU.first, CandSGID, TempEdges);
     LLVM_DEBUG(dbgs() << "Cost of Group " << TempCost << "\n");
+
     if (TempCost < BestNodeCost || BestNodeCost == -1) {
+      BestEdges = TempEdges;
       BestGroup = Match;
       BestNodeCost = TempCost;
       BestGroupID = CandSGID;
+
+      if (BestNodeCost == 0)
+        break;
+
+      removeEdges(BestEdges);
     }
-    removeEdges(AddedEdges);
-    if (BestNodeCost == 0)
-      break;
+
+    removeEdges(TempEdges);
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frederik-h wrote:

Right, keeping only the second one.

https://github.com/llvm/llvm-project/pull/182463