From 27b4fd30ef673b28b3c6014cd56888abfa0e7797 Mon Sep 17 00:00:00 2001
From: Howard Hinnant <hhinnant@apple.com>
Date: Mon, 2 Apr 2012 00:40:41 +0000
Subject: [PATCH] This is an initial commit of constexpr support as proposed by
 Richard Smith.  This by no means completes constexpr support.  Indeed, it
 hardly scratches the surface.  All it does is lay the foundation in
 <__config> and changes those few places in the library that are already using
 that foundation.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153856 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/__config    |  4 +++-
 include/algorithm   |  4 ++--
 include/random      |  4 ++--
 include/type_traits | 13 +++----------
 4 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/include/__config b/include/__config
index 6b290145..7cd01dc1 100644
--- a/include/__config
+++ b/include/__config
@@ -384,7 +384,9 @@ template <unsigned> struct __static_assert_check {};
 #endif
 
 #ifdef _LIBCPP_HAS_NO_CONSTEXPR
-#define constexpr const
+#define _LIBCPP_CONSTEXPR
+#else
+#define _LIBCPP_CONSTEXPR constexpr
 #endif
 
 #ifndef __has_feature
diff --git a/include/algorithm b/include/algorithm
index f9c6843a..68e989a0 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -2712,8 +2712,8 @@ public:
 
     result_type operator()();
 
-    static constexpr result_type min() {return _Min;}
-    static constexpr result_type max() {return _Max;}
+    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
+    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
 
     friend __rs_default __rs_get();
 };
diff --git a/include/random b/include/random
index 02ea9b63..7099af5e 100644
--- a/include/random
+++ b/include/random
@@ -3374,9 +3374,9 @@ public:
     static const result_type _Max = 0xFFFFFFFFu;
 
     _LIBCPP_INLINE_VISIBILITY
-    static constexpr result_type min() { return _Min;}
+    static _LIBCPP_CONSTEXPR result_type min() { return _Min;}
     _LIBCPP_INLINE_VISIBILITY
-    static constexpr result_type max() { return _Max;}
+    static _LIBCPP_CONSTEXPR result_type max() { return _Max;}
 
     // constructors
     explicit random_device(const string& __token = "/dev/urandom");
diff --git a/include/type_traits b/include/type_traits
index 13129f31..f68ed6dd 100644
--- a/include/type_traits
+++ b/include/type_traits
@@ -163,22 +163,15 @@ struct __two {char _[2];};
 template <class _Tp, _Tp __v>
 struct _LIBCPP_VISIBLE integral_constant
 {
-    static constexpr _Tp      value = __v;
+    static _LIBCPP_CONSTEXPR const _Tp      value = __v;
     typedef _Tp               value_type;
     typedef integral_constant type;
     _LIBCPP_INLINE_VISIBILITY
-#ifndef _LIBCPP_HAS_NO_CONSTEXPR
-    constexpr
-#endif
-         operator value_type()
-#ifdef _LIBCPP_HAS_NO_CONSTEXPR
-                               const
-#endif
-                                     {return value;}
+        _LIBCPP_CONSTEXPR operator value_type() const {return value;}
 };
 
 template <class _Tp, _Tp __v>
-constexpr _Tp integral_constant<_Tp, __v>::value;
+_LIBCPP_CONSTEXPR const _Tp integral_constant<_Tp, __v>::value;
 
 typedef integral_constant<bool, true>  true_type;
 typedef integral_constant<bool, false> false_type;