From cd12bf63172e58e1d5d8ed23c96f515e89499851 Mon Sep 17 00:00:00 2001
From: Christoph Hertzberg <chtz@informatik.uni-bremen.de>
Date: Thu, 24 Oct 2019 13:29:35 +0200
Subject: [PATCH] bug #1761: Manually grafted changes in Meta.h
 5937c4ae32feec178d56282694f06ed16cfe7352   Fall back is_integral to
 std::is_integral in c++11 f0862b062fcb613ee6c60745631d90a43d54a6d4   Fix
 internal::is_integral<size_t/ptrdiff_t> with MSVC 2013 and older.

---
 Eigen/src/Core/util/Meta.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Eigen/src/Core/util/Meta.h b/Eigen/src/Core/util/Meta.h
index df72a6911..9b61ff037 100755
--- a/Eigen/src/Core/util/Meta.h
+++ b/Eigen/src/Core/util/Meta.h
@@ -97,6 +97,9 @@ template<> struct is_arithmetic<unsigned int>  { enum { value = true }; };
 template<> struct is_arithmetic<signed long>   { enum { value = true }; };
 template<> struct is_arithmetic<unsigned long> { enum { value = true }; };
 
+#if EIGEN_HAS_CXX11
+using std::is_integral;
+#else
 template<typename T> struct is_integral        { enum { value = false }; };
 template<> struct is_integral<bool>            { enum { value = true }; };
 template<> struct is_integral<char>            { enum { value = true }; };
@@ -108,6 +111,11 @@ template<> struct is_integral<signed int>      { enum { value = true }; };
 template<> struct is_integral<unsigned int>    { enum { value = true }; };
 template<> struct is_integral<signed long>     { enum { value = true }; };
 template<> struct is_integral<unsigned long>   { enum { value = true }; };
+#if EIGEN_COMP_MSVC
+template<> struct is_integral<signed __int64>  { enum { value = true }; };
+template<> struct is_integral<unsigned __int64>{ enum { value = true }; };
+#endif
+#endif
 
 #if EIGEN_HAS_CXX11
 using std::make_unsigned;