[llvm] [MemProf] Remove empty edges once after cloning (PR #85320)

[Teresa Johnson via llvm-commits]

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@@ -2427,11 +2430,42 @@ void CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::
   }
 }
 
+template <typename DerivedCCG, typename FuncTy, typename CallTy>
+void CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::
+    recursivelyRemoveNoneTypeCalleeEdges(
+        ContextNode *Node, DenseSet<const ContextNode *> &Visited) {
+  auto Inserted = Visited.insert(Node);
+  if (!Inserted.second)
+    return;
+
+  removeNoneTypeCalleeEdges(Node);
+
+  for (auto *Clone : Node->Clones)
+    recursivelyRemoveNoneTypeCalleeEdges(Clone, Visited);
+
+  // The recursive call may remove some of this Node's caller edges.
+  // Iterate over a copy and skip any that were removed.
+  auto CallerEdges = Node->CallerEdges;
+  for (auto &Edge : CallerEdges) {
+    // Skip any that have been removed by an earlier recursive call.
+    if (Edge->Callee == nullptr && Edge->Caller == nullptr) {
+      assert(!std::count(Node->CallerEdges.begin(), Node->CallerEdges.end(),
+                         Edge));
+      continue;
+    }
+    recursivelyRemoveNoneTypeCalleeEdges(Edge->Caller, Visited);
+  }
+}
+
 template <typename DerivedCCG, typename FuncTy, typename CallTy>
 void CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::identifyClones() {
   DenseSet<const ContextNode *> Visited;
   for (auto &Entry : AllocationCallToContextNodeMap)
     identifyClones(Entry.second, Visited);
+  Visited.clear();
+  for (auto &Entry : AllocationCallToContextNodeMap)
+    recursivelyRemoveNoneTypeCalleeEdges(Entry.second, Visited);
+  check();
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teresajohnson wrote:

Good catch, this was unconditional from when I was debugging. It should be guarded by the VerifyCCG option like other invocations of this function. Fixed.

https://github.com/llvm/llvm-project/pull/85320