-/// When assertions are off, the Next field of sentinels
-/// will not be accessed. So it is not necessary to allocate
-/// space for it. The following macro selects the most
-/// efficient traits class. The LLVM_COMPACTIFY_SENTINELS
-/// preprocessor symbol controls this.
-///
-#if defined(LLVM_COMPACTIFY_SENTINELS) && LLVM_COMPACTIFY_SENTINELS
-# define ILIST_NODE ilist_half_node
-#else
-# define ILIST_NODE ilist_node
-#endif
+public:
+ /// @name Adjacent Node Accessors
+ /// @{
+
+ /// \brief Get the previous node, or 0 for the list head.
+ NodeTy *getPrevNode() {
+ NodeTy *Prev = this->getPrev();
+
+ // Check for sentinel.
+ if (!Prev->getNext())
+ return 0;
+
+ return Prev;
+ }
+
+ /// \brief Get the previous node, or 0 for the list head.
+ const NodeTy *getPrevNode() const {
+ const NodeTy *Prev = this->getPrev();
+
+ // Check for sentinel.
+ if (!Prev->getNext())
+ return 0;
+
+ return Prev;
+ }
+
+ /// \brief Get the next node, or 0 for the list tail.
+ NodeTy *getNextNode() {
+ NodeTy *Next = getNext();
+
+ // Check for sentinel.
+ if (!Next->getNext())
+ return 0;
+
+ return Next;
+ }
+
+ /// \brief Get the next node, or 0 for the list tail.
+ const NodeTy *getNextNode() const {
+ const NodeTy *Next = getNext();
+
+ // Check for sentinel.
+ if (!Next->getNext())
+ return 0;
+
+ return Next;
+ }
+
+ /// @}
+};