From 218a7b98401aee558b96e21d8ba90641eb3e9371 Mon Sep 17 00:00:00 2001
From: Eugene Zhulenev <ezhulenev@google.com>
Date: Tue, 18 Sep 2018 10:57:00 -0700
Subject: [PATCH] Enable DSizes type promotion with c++03 compilers

---
 .../Eigen/CXX11/src/Tensor/TensorDimensions.h | 20 ++++++++++---------
 unsupported/test/cxx11_tensor_dimension.cpp   |  7 ++++---
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorDimensions.h b/unsupported/Eigen/CXX11/src/Tensor/TensorDimensions.h
index 5de0d0de7..dbf5af094 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorDimensions.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorDimensions.h
@@ -290,22 +290,24 @@ struct DSizes : array<DenseIndex, NumDims> {
     }
   }
 
-#ifdef EIGEN_HAS_CXX11
   // Enable DSizes index type promotion only if we are promoting to the
   // larger type, e.g. allow to promote dimensions of type int to long.
-  template<typename OtherIndex,
-           typename std::enable_if<
-               std::is_same<
-                 DenseIndex,
-                 typename internal::promote_index_type<DenseIndex, OtherIndex>::type
-               >::value, int>::type = 0>
+  template<typename OtherIndex>
   EIGEN_DEVICE_FUNC
-  explicit DSizes(const array<OtherIndex, NumDims>& other) {
+  explicit DSizes(const array<OtherIndex, NumDims>& other,
+                  // Default template parameters require c++11.
+                  typename internal::enable_if<
+                     internal::is_same<
+                         DenseIndex,
+                         typename internal::promote_index_type<
+                             DenseIndex,
+                             OtherIndex
+                         >::type
+                     >::value, void*>::type = 0) {
     for (int i = 0; i < NumDims; ++i) {
       (*this)[i] = static_cast<DenseIndex>(other[i]);
     }
   }
-#endif  // EIGEN_HAS_CXX11
 
 #ifdef EIGEN_HAS_INDEX_LIST
   template <typename FirstType, typename... OtherTypes>
diff --git a/unsupported/test/cxx11_tensor_dimension.cpp b/unsupported/test/cxx11_tensor_dimension.cpp
index 26f8edd8a..ee416e14a 100644
--- a/unsupported/test/cxx11_tensor_dimension.cpp
+++ b/unsupported/test/cxx11_tensor_dimension.cpp
@@ -61,9 +61,11 @@ static void test_rank_zero()
 }
 
 static void test_index_type_promotion() {
-#ifdef EIGEN_HAS_CXX11
   Eigen::DSizes<int, 3> src0(1, 2, 3);
-  Eigen::array<int, 3> src1 = {4, 5, 6};
+  Eigen::array<int, 3> src1;
+  src1[0] = 4;
+  src1[1] = 5;
+  src1[2] = 6;
 
   Eigen::DSizes<long, 3> dst0(src0);
   Eigen::DSizes<long, 3> dst1(src1);
@@ -74,7 +76,6 @@ static void test_index_type_promotion() {
   VERIFY_IS_EQUAL(dst1[0], 4L);
   VERIFY_IS_EQUAL(dst1[1], 5L);
   VERIFY_IS_EQUAL(dst1[2], 6L);
-#endif  // EIGEN_HAS_CXX11
 }
 
 EIGEN_DECLARE_TEST(cxx11_tensor_dimension)