[NFC][SYCL][Graph] Store raw node_impl * in MPredecessors/MSuccessors

sycl/source/detail/graph/graph_impl.cpp

@@ -1321,11 +1321,9 @@ void exec_graph_impl::duplicateNodes() {
       auto &Successors = PredNode.MSuccessors;
 
       // Remove the subgraph node from this nodes successors
-      Successors.erase(std::remove_if(Successors.begin(), Successors.end(),
-                                      [NewNode](auto WeakNode) {
-                                        return WeakNode.lock() == NewNode;
-                                      }),
-                       Successors.end());
+      Successors.erase(
+          std::remove(Successors.begin(), Successors.end(), NewNode.get()),
+          Successors.end());
 
       // Add all input nodes from the subgraph as successors for this node
       // instead
@@ -1339,12 +1337,9 @@ void exec_graph_impl::duplicateNodes() {
       auto &Predecessors = SuccNode.MPredecessors;
 
       // Remove the subgraph node from this nodes successors
-      Predecessors.erase(std::remove_if(Predecessors.begin(),
-                                        Predecessors.end(),
-                                        [NewNode](auto WeakNode) {
-                                          return WeakNode.lock() == NewNode;
-                                        }),
-                         Predecessors.end());
+      Predecessors.erase(
+          std::remove(Predecessors.begin(), Predecessors.end(), NewNode.get()),
+          Predecessors.end());
 
       // Add all Output nodes from the subgraph as predecessors for this node
       // instead

sycl/source/detail/graph/node_impl.hpp

@@ -93,11 +93,11 @@ class node_impl : public std::enable_shared_from_this<node_impl> {
   /// Unique identifier for this node.
   id_type MID = getNextNodeID();
   /// List of successors to this node.
-  std::vector<std::weak_ptr<node_impl>> MSuccessors;
+  std::vector<node_impl *> MSuccessors;
   /// List of predecessors to this node.
   ///
   /// Using weak_ptr here to prevent circular references between nodes.
-  std::vector<std::weak_ptr<node_impl>> MPredecessors;
+  std::vector<node_impl *> MPredecessors;
   /// Type of the command-group for the node.
   sycl::detail::CGType MCGType = sycl::detail::CGType::None;
   /// User facing type of the node.
@@ -123,26 +123,22 @@ class node_impl : public std::enable_shared_from_this<node_impl> {
   /// Add successor to the node.
   /// @param Node Node to add as a successor.
   void registerSuccessor(node_impl &Node) {
-    if (std::find_if(MSuccessors.begin(), MSuccessors.end(),
-                     [&Node](const std::weak_ptr<node_impl> &Ptr) {
-                       return Ptr.lock().get() == &Node;
-                     }) != MSuccessors.end()) {
+    if (std::find(MSuccessors.begin(), MSuccessors.end(), &Node) !=
+        MSuccessors.end()) {
       return;
     }
-    MSuccessors.push_back(Node.weak_from_this());
+    MSuccessors.push_back(&Node);
     Node.registerPredecessor(*this);
   }
 
   /// Add predecessor to the node.
   /// @param Node Node to add as a predecessor.
   void registerPredecessor(node_impl &Node) {
-    if (std::find_if(MPredecessors.begin(), MPredecessors.end(),
-                     [&Node](const std::weak_ptr<node_impl> &Ptr) {
-                       return Ptr.lock().get() == &Node;
-                     }) != MPredecessors.end()) {
+    if (std::find(MPredecessors.begin(), MPredecessors.end(), &Node) !=
+        MPredecessors.end()) {
       return;
     }
-    MPredecessors.push_back(Node.weak_from_this());
+    MPredecessors.push_back(&Node);
   }
 
   /// Construct an empty node.
@@ -393,15 +389,13 @@ class node_impl : public std::enable_shared_from_this<node_impl> {
     Visited.push_back(this);
 
     printDotCG(Stream, Verbose);
-    for (const auto &Dep : MPredecessors) {
-      auto NodeDep = Dep.lock();
-      Stream << "  \"" << NodeDep.get() << "\" -> \"" << this << "\""
-             << std::endl;
+    for (node_impl *Pred : MPredecessors) {
+      Stream << "  \"" << Pred << "\" -> \"" << this << "\"" << std::endl;
     }
 
-    for (std::weak_ptr<node_impl> Succ : MSuccessors) {
-      if (MPartitionNum == Succ.lock()->MPartitionNum)
-        Succ.lock()->printDotRecursive(Stream, Visited, Verbose);
+    for (node_impl *Succ : MSuccessors) {
+      if (MPartitionNum == Succ->MPartitionNum)
+        Succ->printDotRecursive(Stream, Visited, Verbose);
     }
   }