+// IA-64 uses function descriptors not function pointers in its vtables.
+#if defined __ia64__
+#define CMP_VPTR(A, B) (*(void **)(A) == *(void **)(B))
+#ifdef _LP64
+#define INC_VPTR(A) ((A) += 2)
+#define INC_VDATA(A,N) ((A) += (N))
+#else
+#define INC_VPTR(A) ((A) += 4)
+#define INC_VDATA(A,N) ((A) += 2*(N))
+#endif
+#else
+#define CMP_VPTR(A, B) (*(A) == (ptrdiff_t)(B))
+#define INC_VPTR(A) ((A) += 1)
+#define INC_VDATA(A,N) ((A) += (N))
+#endif
+