string.c: optimize enumerate_grapheme_clusters

* string.c (rb_str_enumerate_grapheme_clusters): optimize when
  single byte only.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59762 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 1 deletions

diff --git a/string.c b/string.c
index abaae1e726..734184085c 100644
--- a/string.c
+++ b/string.c
@@ -8027,7 +8027,7 @@ rb_str_enumerate_grapheme_clusters(VALUE str, VALUE ary)
     int unicode_p = rb_enc_unicode_p(enc);
     const char *ptr, *end;
 
-    if (!unicode_p) {
+    if (!unicode_p || single_byte_optimizable(str)) {
 	return rb_str_enumerate_chars(str, ary);
     }