diff --git a/ChangeLog b/ChangeLog
index fbf82ba205..95a106da21 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Fri Sep 11 02:06:44 2009  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* parse.y (rb_char_to_option_kcode): ASCII-8BIT should
+	  also delay.
+
+	* re.c (parser_regx_options): return rb_ascii8bit_encindex on
+	  ASCII-8BIT. [ruby-dev:39300]
+
 Fri Sep 11 01:14:00 2009  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
 
 	* lib/net/http.rb (fetch): rdoc fix, patch by Arthur Schreiber.
diff --git a/parse.y b/parse.y
index 121029d19d..26283aa6e5 100644
--- a/parse.y
+++ b/parse.y
@@ -5598,8 +5598,13 @@ parser_regx_options(struct parser_params *parser)
             options |= RE_OPTION_ONCE;
         }
         else if (rb_char_to_option_kcode(c, &opt, &kc)) {
-            kopt = opt;
-	    if (kc >= 0) kcode = c;
+	    if (kc >= 0) {
+		if (kc != rb_ascii8bit_encindex()) kcode = c;
+		kopt = opt;
+	    }
+	    else {
+		options |= opt;
+	    }
         }
         else {
 	    tokadd(c);
diff --git a/re.c b/re.c
index 2d7ea2c4c3..e22c8c04c2 100644
--- a/re.c
+++ b/re.c
@@ -287,7 +287,7 @@ rb_char_to_option_kcode(int c, int *option, int *kcode)
 
     switch (c) {
       case 'n':
-        *kcode = -1;
+        *kcode = rb_ascii8bit_encindex();
         return (*option = ARG_ENCODING_NONE);
       case 'e':
 	*kcode = rb_enc_find_index("EUC-JP");
@@ -296,7 +296,7 @@ rb_char_to_option_kcode(int c, int *option, int *kcode)
 	*kcode = rb_enc_find_index("Windows-31J");
 	break;
       case 'u':
-	*kcode = rb_enc_find_index("UTF-8");
+	*kcode = rb_utf8_encindex();
 	break;
       default:
 	*kcode = -1;