[llvm] 133ac3a - [ADT] Achieve the "Rule of Zero" in DGNode (#165190)

[via llvm-commits]

Author: Kazu Hirata
Date: 2025-10-26T22:09:40-07:00
New Revision: 133ac3ad3fe87f9b3c21748d3421e65977605756

URL: https://github.com/llvm/llvm-project/commit/133ac3ad3fe87f9b3c21748d3421e65977605756
DIFF: https://github.com/llvm/llvm-project/commit/133ac3ad3fe87f9b3c21748d3421e65977605756.diff

LOG: [ADT] Achieve the "Rule of Zero" in DGNode (#165190)

This patch achieves the "Rule of Zero" in DGNode by removing the
copy/move constructors and copy/move assignment operators.

Note that the code being deleted does a couple of unusual things that
are most likely oversight:

- The copy constructor with "explicit" is highly unusual.  This means
  that we allow "DGNode<N, E> A(B);" but disallow
  "DGNode<N, E> A = B;".

- The move assignment operator with const r-value reference is also
  unusual, especially given that the move constructor is correctly
  implemented.

Added: 
    

Modified: 
    llvm/include/llvm/ADT/DirectedGraph.h

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/ADT/DirectedGraph.h b/llvm/include/llvm/ADT/DirectedGraph.h
index fb6b180f77e6b..fe7c9e51cbd9a 100644
--- a/llvm/include/llvm/ADT/DirectedGraph.h
+++ b/llvm/include/llvm/ADT/DirectedGraph.h
@@ -80,18 +80,6 @@ template <class NodeType, class EdgeType> class DGNode {
   explicit DGNode(EdgeType &E) : Edges() { Edges.insert(&E); }
   DGNode() = default;
 
-  explicit DGNode(const DGNode<NodeType, EdgeType> &N) : Edges(N.Edges) {}
-  DGNode(DGNode<NodeType, EdgeType> &&N) : Edges(std::move(N.Edges)) {}
-
-  DGNode<NodeType, EdgeType> &operator=(const DGNode<NodeType, EdgeType> &N) {
-    Edges = N.Edges;
-    return *this;
-  }
-  DGNode<NodeType, EdgeType> &operator=(const DGNode<NodeType, EdgeType> &&N) {
-    Edges = std::move(N.Edges);
-    return *this;
-  }
-
   /// Static polymorphism: delegate implementation (via isEqualTo) to the
   /// derived class.
   friend bool operator==(const NodeType &M, const NodeType &N) {