diff --git a/ext/pcre/php_pcre.c b/ext/pcre/php_pcre.c
index 7aa879d26db..5165209b85d 100644
--- a/ext/pcre/php_pcre.c
+++ b/ext/pcre/php_pcre.c
@@ -739,7 +739,7 @@ PHPAPI pcre_cache_entry* pcre_get_compiled_regex_cache(zend_string *regex)
 				efree(pattern);
 				return NULL;
 			}
-			_k = zend_string_dup(BG(locale_string), 1);
+			_k = zend_string_init(ZSTR_VAL(BG(locale_string)), ZSTR_LEN(BG(locale_string)), 1);
 			zend_hash_add_ptr(&char_tables, _k, (void *)tables);
 			zend_string_release(_k);
 		}