From 2a5349ba6661a8e022093d79660e81f120a1f205 Mon Sep 17 00:00:00 2001
From: Howard Hinnant <hhinnant@apple.com>
Date: Tue, 3 Apr 2012 21:09:48 +0000
Subject: [PATCH] constexpr support for <utility>.  Patch contributed by
 Jonathan Sauer.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153968 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/utility | 7 +++++--
 src/utility.cpp | 2 ++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/utility b/include/utility
index 7facea3a6..a12ed91e7 100644
--- a/include/utility
+++ b/include/utility
@@ -206,8 +206,11 @@ move_if_noexcept(_Tp& __x) _NOEXCEPT
 }
 
 struct _LIBCPP_VISIBLE piecewise_construct_t { };
-//constexpr
+#ifdef _LIBCPP_HAS_NO_CONSTEXPR
 extern const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
+#else
+constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
+#endif
 
 template <class _T1, class _T2>
 struct _LIBCPP_VISIBLE pair
@@ -221,7 +224,7 @@ struct _LIBCPP_VISIBLE pair
     // pair(const pair&) = default;
     // pair(pair&&) = default;
 
-    _LIBCPP_INLINE_VISIBILITY pair() : first(), second() {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR pair() : first(), second() {}
 
     _LIBCPP_INLINE_VISIBILITY pair(const _T1& __x, const _T2& __y)
         : first(__x), second(__y) {}
diff --git a/src/utility.cpp b/src/utility.cpp
index 7dccffb73..deb5ffa00 100644
--- a/src/utility.cpp
+++ b/src/utility.cpp
@@ -11,6 +11,8 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+#ifdef _LIBCPP_HAS_NO_CONSTEXPR
 const piecewise_construct_t piecewise_construct = {};
+#endif
 
 _LIBCPP_END_NAMESPACE_STD