diff --git a/ChangeLog b/ChangeLog
index 71cdfdcf07..6fff51848a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Feb 14 07:23:52 2009  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* string.c (rb_external_str_new_with_enc): change evaluatioin order
+	  for speed.
+
 Sat Feb 14 02:20:04 2009  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/sockport.h (SET_SA_LEN): cast to void for supressing a
diff --git a/string.c b/string.c
index 8eb83efcec..28410a448c 100644
--- a/string.c
+++ b/string.c
@@ -538,8 +538,8 @@ rb_external_str_new_with_enc(const char *ptr, long len, rb_encoding *eenc)
     VALUE str;
 
     str = rb_tainted_str_new(ptr, len);
-    if (rb_enc_str_coderange(str) != ENC_CODERANGE_7BIT &&
-	eenc == rb_usascii_encoding()) {
+    if (eenc == rb_usascii_encoding() &&
+	rb_enc_str_coderange(str) != ENC_CODERANGE_7BIT) {
 	rb_enc_associate(str, rb_ascii8bit_encoding());
 	return str;
     }