From f1fbb45134065deebe95249c616a967d4b66c809 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Mon, 13 Mar 2023 13:32:29 +0100
Subject: [PATCH] Use [[msvc::intrinsic] attribute if available in move/forward
 in order to improve debug experience

---
 include/boost/move/detail/workaround.hpp | 14 ++++++++++++++
 include/boost/move/utility.hpp           |  4 ++--
 include/boost/move/utility_core.hpp      |  9 ++++++---
 3 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/include/boost/move/detail/workaround.hpp b/include/boost/move/detail/workaround.hpp
index 1ca5c1d..2fcd027 100644
--- a/include/boost/move/detail/workaround.hpp
+++ b/include/boost/move/detail/workaround.hpp
@@ -130,5 +130,19 @@ template<unsigned> struct static_assert_test {};
 
 #endif
 
+#if !defined(__has_cpp_attribute) || defined(__CUDACC__)
+#define BOOST_MOVE_HAS_MSVC_ATTRIBUTE(ATTR) 0
+#else
+#define BOOST_MOVE_HAS_MSVC_ATTRIBUTE(ATTR) __has_cpp_attribute(msvc::ATTR)
+#endif
+
+// See https://devblogs.microsoft.com/cppblog/improving-the-state-of-debug-performance-in-c/
+// for details on how MSVC has improved debug experience, specifically for move/forward-like utilities
+#if BOOST_MOVE_HAS_MSVC_ATTRIBUTE(intrinsic)
+#define BOOST_MOVE_INTRINSIC_CAST [[msvc::intrinsic]]
+#else
+#define BOOST_MOVE_INTRINSIC_CAST BOOST_MOVE_FORCEINLINE
+#endif
+
 #endif   //#ifndef BOOST_MOVE_DETAIL_WORKAROUND_HPP
 
diff --git a/include/boost/move/utility.hpp b/include/boost/move/utility.hpp
index 28de793..9c94d77 100644
--- a/include/boost/move/utility.hpp
+++ b/include/boost/move/utility.hpp
@@ -126,13 +126,13 @@
       #else //BOOST_MOVE_DOXYGEN_INVOKED
 
          template <class T>
-         BOOST_MOVE_FORCEINLINE typename ::boost::move_detail::enable_if_c
+         BOOST_MOVE_INTRINSIC_CAST typename ::boost::move_detail::enable_if_c
             < ::boost::move_detail::is_nothrow_move_constructible_or_uncopyable<T>::value, T&&>::type
                move_if_noexcept(T& x) BOOST_NOEXCEPT
          {  return ::boost::move(x);   }
 
          template <class T>
-         BOOST_MOVE_FORCEINLINE typename ::boost::move_detail::enable_if_c
+         BOOST_MOVE_INTRINSIC_CAST typename ::boost::move_detail::enable_if_c
             < !::boost::move_detail::is_nothrow_move_constructible_or_uncopyable<T>::value, const T&>::type
                move_if_noexcept(T& x) BOOST_NOEXCEPT
          {  return x;  }
diff --git a/include/boost/move/utility_core.hpp b/include/boost/move/utility_core.hpp
index 814ba08..907b764 100644
--- a/include/boost/move/utility_core.hpp
+++ b/include/boost/move/utility_core.hpp
@@ -208,7 +208,8 @@
       #else //BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES
 
          template <class T>
-         BOOST_MOVE_FORCEINLINE typename ::boost::move_detail::remove_reference<T>::type && move(T&& t) BOOST_NOEXCEPT
+         BOOST_MOVE_INTRINSIC_CAST
+         typename ::boost::move_detail::remove_reference<T>::type && move(T&& t) BOOST_NOEXCEPT
          { return static_cast<typename ::boost::move_detail::remove_reference<T>::type &&>(t); }
 
       #endif   //BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES
@@ -244,11 +245,13 @@
       #else //Old move
 
          template <class T>
-         BOOST_MOVE_FORCEINLINE T&& forward(typename ::boost::move_detail::remove_reference<T>::type& t) BOOST_NOEXCEPT
+         BOOST_MOVE_INTRINSIC_CAST
+         T&& forward(typename ::boost::move_detail::remove_reference<T>::type& t) BOOST_NOEXCEPT
          {  return static_cast<T&&>(t);   }
 
          template <class T>
-         BOOST_MOVE_FORCEINLINE T&& forward(typename ::boost::move_detail::remove_reference<T>::type&& t) BOOST_NOEXCEPT
+         BOOST_MOVE_INTRINSIC_CAST
+         T&& forward(typename ::boost::move_detail::remove_reference<T>::type&& t) BOOST_NOEXCEPT
          {
             //"boost::forward<T> error: 'T' is a lvalue reference, can't forward as rvalue.";
             BOOST_MOVE_STATIC_ASSERT(!boost::move_detail::is_lvalue_reference<T>::value);