From 3ac40452727a837f55aa1f3f484d5e8c52d6d769 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Wed, 25 May 2016 15:15:12 -0700
Subject: [PATCH] Made the IndexPair code compile in non cxx11 mode

---
 unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h b/unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h
index 9ae97ba42..b1645d56f 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h
@@ -114,8 +114,8 @@ bool operator!=(const Tuple<U, V>& x, const Tuple<U, V>& y) {
 
 // Can't use std::pairs on cuda devices
 template <typename Idx> struct IndexPair {
-  constexpr EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE IndexPair() : first(0), second(0) {}
-  constexpr EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE IndexPair(Idx f, Idx s) : first(f), second(s) {}
+  EIGEN_CONSTEXPR EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE IndexPair() : first(0), second(0) {}
+  EIGEN_CONSTEXPR EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE IndexPair(Idx f, Idx s) : first(f), second(s) {}
 
   EIGEN_DEVICE_FUNC void set(IndexPair<Idx> val) {
     first = val.first;