Move the test for zero-length into the char_traits (from string_view). Add tests to char_traits specializations git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@228981 91177308-0d34-0410-b5e6-96231b3b80d8 
diff --git a/include/string b/include/string index fe42bbf..9f4007a 100644 --- a/include/string +++ b/include/string 
@@ -636,7 +636,7 @@  {return (unsigned char)__c1 < (unsigned char)__c2;}    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n) - {return memcmp(__s1, __s2, __n);} + {return __n == 0 ? 0 : memcmp(__s1, __s2, __n);}  static inline size_t length(const char_type* __s) {return strlen(__s);}  static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a)  {return (const char_type*)memchr(__s, to_int_type(__a), __n);} @@ -681,7 +681,7 @@  {return __c1 < __c2;}    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n) - {return wmemcmp(__s1, __s2, __n);} + {return __n == 0 ? 0 : wmemcmp(__s1, __s2, __n);}  static inline size_t length(const char_type* __s)  {return wcslen(__s);}  static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a)