diff --git a/ChangeLog b/ChangeLog
index 11bd451833..896e278b4e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jun 12 13:36:54 2008  Tanaka Akira  <akr@fsij.org>
+
+	* include/ruby/ruby.h (rb_intern): use rb_intern2 with strlen for
+	  constant symbols to optimize strlen.
+
 Thu Jun 12 08:47:51 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* io.c (read_all): should use io_read_encoding(), not
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 5bae5d392d..d2b9f4c8b3 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -768,7 +768,7 @@ VALUE rb_id2str(ID);
     {							\
 	static ID rb_intern_id_cache;			\
 	if (!rb_intern_id_cache)			\
-	    rb_intern_id_cache = (rb_intern)(str);	\
+	    rb_intern_id_cache = rb_intern2(str, strlen(str));	\
 	result rb_intern_id_cache;			\
     }
 #define CONST_ID(var, str) \