[PATCH] D26896: [libcxx] Make constexpr char_traits<T> and char_traits<char>

[Anton Bikineev via cfe-commits]

AntonBikineev marked 2 inline comments as done.
AntonBikineev added inline comments.


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Comment at: include/__config:925
 
+#if !__has_builtin(__builtin_memcpy)
+#define _LIBCPP_HAS_NO_BUILTIN_MEMCPY
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EricWF wrote:
> What about GCC? Surely it implements some if not most of these.
Thanks, good point. I've done it in the same way as it is done for __buitin_addressof. On the other hand, gcc has an option -fno-builtin to disable them. That way it *won't* compile. I try to stick to the current solution though.


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Comment at: include/__string:213
 
-    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
-        {return __n == 0 ? 0 : memcmp(__s1, __s2, __n);}
-    static inline size_t length(const char_type* __s)  _NOEXCEPT {return strlen(__s);}
-    static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT
-        {return __n == 0 ? NULL : (const char_type*) memchr(__s, to_int_type(__a), __n);}
+#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_CXX14_CONSTEXPR)
+    static inline constexpr int
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EricWF wrote:
> wow. This is #ifdef hell. Please find a way to do it with less (or hopefully no) conditional compilation blocks.
yep, this is generic hell. I want to cover as many cases as possible, i.e. combinations of (is_constexpr x has_builtin_xxx) for every function. I'm open to suggestions


https://reviews.llvm.org/D26896