analyzer: add program_point::get_next

Avoid some future copy-and-paste by introducing a function.

gcc/analyzer/ChangeLog:
	* engine.cc
	(exploded_graph::process_node) <case PK_BEFORE_SUPERNODE>:
	Simplify by using program_point::get_next.
	* program-point.cc (program_point::get_next): New.
	* program-point.h (program_point::get_next): New decl.

gcc/analyzer/engine.cc

@@ -2458,26 +2458,10 @@ exploded_graph::process_node (exploded_node *node)
 		 &ctxt);
 	  }
 
-	if (point.get_supernode ()->m_stmts.length () > 0)
-	  {
-	    program_point next_point
-	      = program_point::before_stmt (point.get_supernode (), 0,
-					    point.get_call_string ());
-	    exploded_node *next
-	      = get_or_create_node (next_point, next_state, node);
-	    if (next)
-	      add_edge (node, next, NULL);
-	  }
-	else
-	  {
-	    program_point next_point
-	      = program_point::after_supernode (point.get_supernode (),
-						point.get_call_string ());
-	    exploded_node *next = get_or_create_node (next_point, next_state,
-						      node);
-	    if (next)
-	      add_edge (node, next, NULL);
-	  }
+	program_point next_point (point.get_next ());
+	exploded_node *next = get_or_create_node (next_point, next_state, node);
+	if (next)
+	  add_edge (node, next, NULL);
       }
       break;
     case PK_BEFORE_STMT:

gcc/analyzer/program-point.cc

@@ -529,6 +529,35 @@ function_point::next_stmt ()
     }
 }
 
+/* For those program points for which there is a uniquely-defined
+   successor, return it.  */
+
+program_point
+program_point::get_next () const
+{
+  switch (m_function_point.get_kind ())
+    {
+    default:
+      gcc_unreachable ();
+    case PK_ORIGIN:
+    case PK_AFTER_SUPERNODE:
+      gcc_unreachable (); /* Not uniquely defined.  */
+    case PK_BEFORE_SUPERNODE:
+      if (get_supernode ()->m_stmts.length () > 0)
+	return before_stmt (get_supernode (), 0, get_call_string ());
+      else
+	return after_supernode (get_supernode (), get_call_string ());
+    case PK_BEFORE_STMT:
+      {
+	unsigned next_idx = get_stmt_idx ();
+	if (next_idx < get_supernode ()->m_stmts.length ())
+	  return before_stmt (get_supernode (), next_idx, get_call_string ());
+	else
+	  return after_supernode (get_supernode (), get_call_string ());
+      }
+    }
+}
+
 #if CHECKING_P
 
 namespace selftest {

gcc/analyzer/program-point.h

@@ -294,6 +294,8 @@ public:
   /* For before_stmt, go to next stmt.  */
   void next_stmt () { m_function_point.next_stmt (); }
 
+  program_point get_next () const;
+
  private:
   function_point m_function_point;
   call_string m_call_string;