From e9ecfad7967fd5285846647372897ecdc125f976 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Thu, 12 Nov 2015 16:41:14 -0800
Subject: [PATCH] Started to make the IndexList code compile by more compilers

---
 .../CXX11/src/Tensor/TensorDimensionList.h    | 16 +++++-----
 .../Eigen/CXX11/src/Tensor/TensorIndexList.h  | 30 +++++++++++--------
 .../Eigen/CXX11/src/Tensor/TensorReduction.h  |  8 ++---
 3 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorDimensionList.h b/unsupported/Eigen/CXX11/src/Tensor/TensorDimensionList.h
index 17d89d5e1..da7782188 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorDimensionList.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorDimensionList.h
@@ -72,14 +72,14 @@ struct all_indices_known_statically<const DimensionList<Index, Rank> > {
 };
 
 template <typename Index, std::size_t Rank>
-struct indices_statically_known_to_increase<DimensionList<Index, Rank> > {
-  constexpr bool operator() () const {
+struct indices_statically_known_to_increase_impl<DimensionList<Index, Rank> > {
+  static constexpr bool run() {
     return true;
   }
 };
 template <typename Index, std::size_t Rank>
-struct indices_statically_known_to_increase<const DimensionList<Index, Rank> > {
-  constexpr bool operator() () const {
+struct indices_statically_known_to_increase_impl<const DimensionList<Index, Rank> > {
+  static constexpr bool run() {
     return true;
   }
 };
@@ -164,14 +164,14 @@ struct all_indices_known_statically<const DimensionList<Index, Rank> > {
 };
 
 template <typename Index, std::size_t Rank>
-struct indices_statically_known_to_increase<DimensionList<Index, Rank> > {
-  EIGEN_ALWAYS_INLINE bool operator() () const {
+struct indices_statically_known_to_increase_impl<DimensionList<Index, Rank> > {
+  static EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE bool run() {
     return true;
   }
 };
 template <typename Index, std::size_t Rank>
-struct indices_statically_known_to_increase<const DimensionList<Index, Rank> > {
-  EIGEN_ALWAYS_INLINE bool operator() () const {
+struct indices_statically_known_to_increase_impl<const DimensionList<Index, Rank> > {
+  static EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE bool run() {
     return true;
   }
 };
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorIndexList.h b/unsupported/Eigen/CXX11/src/Tensor/TensorIndexList.h
index dcd2464f1..69d21d3c1 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorIndexList.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorIndexList.h
@@ -336,26 +336,32 @@ struct all_indices_known_statically<const IndexList<FirstType, OtherTypes...> >
 };
 
 template <typename T>
-struct indices_statically_known_to_increase {
-  constexpr bool operator() () const {
+struct indices_statically_known_to_increase_impl {
+  static constexpr bool run() {
     return false;
   }
 };
 
 template <typename FirstType, typename... OtherTypes>
-struct indices_statically_known_to_increase<IndexList<FirstType, OtherTypes...> > {
-  constexpr bool operator() () const {
-    return IndexList<FirstType, OtherTypes...>().values_statically_known_to_increase();
+  struct indices_statically_known_to_increase_impl<IndexList<FirstType, OtherTypes...> > {
+  static constexpr bool run() {
+    return Eigen::IndexList<FirstType, OtherTypes...>().values_statically_known_to_increase();
   }
 };
 
 template <typename FirstType, typename... OtherTypes>
-struct indices_statically_known_to_increase<const IndexList<FirstType, OtherTypes...> > {
-  constexpr bool operator() () const {
-    return IndexList<FirstType, OtherTypes...>().values_statically_known_to_increase();
+  struct indices_statically_known_to_increase_impl<const IndexList<FirstType, OtherTypes...> > {
+  static constexpr bool run() {
+    return Eigen::IndexList<FirstType, OtherTypes...>().values_statically_known_to_increase();
   }
 };
 
+template <typename T>
+static constexpr bool indices_statically_known_to_increase() {
+  return indices_statically_known_to_increase_impl<T>::run();
+}
+
+
 template <typename Tx>
 struct index_statically_eq {
   constexpr bool operator() (DenseIndex, DenseIndex) const {
@@ -473,11 +479,9 @@ struct all_indices_known_statically {
 };
 
 template <typename T>
-struct indices_statically_known_to_increase {
-  EIGEN_ALWAYS_INLINE EIGEN_DEVICE_FUNC bool operator() () const {
-    return false;
-  }
-};
+static EIGEN_ALWAYS_INLINE EIGEN_DEVICE_FUNC bool indices_statically_known_to_increase() {
+  return false;
+}
 
 template <typename T>
 struct index_statically_eq {
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h b/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
index c1cdb98a4..4d3e25d87 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
@@ -88,14 +88,14 @@ struct preserve_inner_most_dims {
 #if defined(EIGEN_HAS_CONSTEXPR) && defined(EIGEN_HAS_VARIADIC_TEMPLATES)
 template <typename ReducedDims, int NumTensorDims>
 struct are_inner_most_dims<ReducedDims, NumTensorDims, ColMajor>{
-  static const bool tmp1 = indices_statically_known_to_increase<ReducedDims>()();
+  static const bool tmp1 = indices_statically_known_to_increase<ReducedDims>();
   static const bool tmp2 = index_statically_eq<ReducedDims>()(0, 0);
   static const bool tmp3 = index_statically_eq<ReducedDims>()(array_size<ReducedDims>::value-1, array_size<ReducedDims>::value-1);
   static const bool value = tmp1 & tmp2 & tmp3;
 };
 template <typename ReducedDims, int NumTensorDims>
 struct are_inner_most_dims<ReducedDims, NumTensorDims, RowMajor>{
-  static const bool tmp1 = indices_statically_known_to_increase<ReducedDims>()();
+  static const bool tmp1 = indices_statically_known_to_increase<ReducedDims>();
   static const bool tmp2 = index_statically_eq<ReducedDims>()(0, NumTensorDims - array_size<ReducedDims>::value);
   static const bool tmp3 = index_statically_eq<ReducedDims>()(array_size<ReducedDims>::value - 1, NumTensorDims - 1);
   static const bool value = tmp1 & tmp2 & tmp3;
@@ -103,14 +103,14 @@ struct are_inner_most_dims<ReducedDims, NumTensorDims, RowMajor>{
 };
 template <typename ReducedDims, int NumTensorDims>
 struct preserve_inner_most_dims<ReducedDims, NumTensorDims, ColMajor>{
-  static const bool tmp1 = indices_statically_known_to_increase<ReducedDims>()();
+  static const bool tmp1 = indices_statically_known_to_increase<ReducedDims>();
   static const bool tmp2 = index_statically_gt<ReducedDims>()(0, 0);
   static const bool value = tmp1 & tmp2;
 
 };
 template <typename ReducedDims, int NumTensorDims>
 struct preserve_inner_most_dims<ReducedDims, NumTensorDims, RowMajor>{
-  static const bool tmp1 = indices_statically_known_to_increase<ReducedDims>()();
+  static const bool tmp1 = indices_statically_known_to_increase<ReducedDims>();
   static const bool tmp2 = index_statically_lt<ReducedDims>()(array_size<ReducedDims>::value - 1, NumTensorDims - 1);
   static const bool value = tmp1 & tmp2;
 };