diff --git a/ChangeLog b/ChangeLog
index 06019849f5..6307433226 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Sat Jun 14 16:58:41 2003  Guy Decoux  <ts@moulon.inra.fr>
+
+	* regex.c (calculate_must_string): should handle option_set
+	  properly. [ruby-talk:73481]
+
+	* regex.c (re_compile_fastmap): a bug in flag manipulation.
+	  [ruby-talk:73549]
+
 Sat Jun 14 17:59:59 2003  Guy Decoux  <ts@moulon.inra.fr>
 
 	* eval.c (method_arity): should handle NODE_BMETHOD and
diff --git a/regex.c b/regex.c
index 57ce31fe33..4ac18cb3a0 100644
--- a/regex.c
+++ b/regex.c
@@ -1037,6 +1037,7 @@ calculate_must_string(start, end)
       break;
 
     case duplicate:
+    case option_set:
       p++;
       break;
 
@@ -1062,7 +1063,6 @@ calculate_must_string(start, end)
     case push_dummy_failure:
     case start_paren:
     case stop_paren:
-    case option_set:
       break;
 
     case charset:
@@ -2815,8 +2815,11 @@ re_compile_fastmap(bufp)
 
       case casefold_on:
 	bufp->options |= RE_MAY_IGNORECASE;
+	options |= RE_OPTION_IGNORECASE;
+	continue;
+
       case casefold_off:
-	options ^= RE_OPTION_IGNORECASE;
+	options &= ~RE_OPTION_IGNORECASE;
 	continue;
 
       case option_set: