Const-correctness fixes for fibonacci_heap.h

gcc/ChangeLog:
	* fibonacci_heap.h (fibonacci_heap::empty): Make const.
	(fibonacci_heap::nodes): Likewise.
	(fibonacci_heap::min_key): Likewise.
	(fibonacci_heap::min): Likewise.

From-SVN: r276193

gcc/ChangeLog

 2019-09-27  David Malcolm  <dmalcolm@redhat.com>
 
+	* fibonacci_heap.h (fibonacci_heap::empty): Make const.
+	(fibonacci_heap::nodes): Likewise.
+	(fibonacci_heap::min_key): Likewise.
+	(fibonacci_heap::min): Likewise.
+
+2019-09-27  David Malcolm  <dmalcolm@redhat.com>
+
 	* cgraph.c (cgraph_node::get_fun): Make const.
 	* cgraph.h (cgraph_node::get_fun): Likewise.
 

gcc/fibonacci_heap.h

@@ -162,19 +162,19 @@ public:
   fibonacci_node_t *insert (K key, V *data);
 
   /* Return true if no entry is present.  */
-  bool empty ()
+  bool empty () const
   {
     return m_nodes == 0;
   }
 
   /* Return the number of nodes.  */
-  size_t nodes ()
+  size_t nodes () const
   {
     return m_nodes;
   }
 
   /* Return minimal key presented in the heap.  */
-  K min_key ()
+  K min_key () const
   {
     if (m_min == NULL)
       gcc_unreachable ();
@@ -206,7 +206,7 @@ public:
   V *extract_min (bool release = true);
 
   /* Return value associated with minimum node in the heap.  */
-  V *min ()
+  V *min () const
   {
     if (m_min == NULL)
       return NULL;