From b80036abec3c008306852334d7c8f057fee11d54 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Mon, 13 Jul 2015 11:16:37 -0700
Subject: [PATCH] Enabled the construction of a fixed sized tensor directly
 from an expression.

---
 unsupported/Eigen/CXX11/src/Tensor/TensorBase.h |  2 ++
 .../Eigen/CXX11/src/Tensor/TensorFixedSize.h    | 17 +++++++++++++++++
 unsupported/test/cxx11_tensor_intdiv.cpp        | 13 +++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h b/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
index 165bd8a89..ca712f9c5 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
@@ -492,6 +492,7 @@ class TensorBase<Derived, ReadOnlyAccessors>
 
   protected:
     template <typename Scalar, std::size_t NumIndices, int Options, typename IndexType> friend class Tensor;
+   template <typename Scalar, typename Dimensions, int Option, typename IndexTypes> friend class TensorFixedSize;
     template <typename OtherDerived, int AccessLevel> friend class TensorBase;
     EIGEN_DEVICE_FUNC
     EIGEN_STRONG_INLINE const Derived& derived() const { return *static_cast<const Derived*>(this); }
@@ -508,6 +509,7 @@ class TensorBase<Derived, WriteAccessors> : public TensorBase<Derived, ReadOnlyA
     static const int NumDimensions = DerivedTraits::NumDimensions;
 
     template <typename Scalar, std::size_t NumIndices, int Options, typename IndexType> friend class Tensor;
+    template <typename Scalar, typename Dimensions, int Option, typename IndexTypes> friend class TensorFixedSize;
     template <typename OtherDerived, int AccessLevel> friend class TensorBase;
 
     EIGEN_DEVICE_FUNC
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorFixedSize.h b/unsupported/Eigen/CXX11/src/Tensor/TensorFixedSize.h
index 76998b690..5e511dc4b 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorFixedSize.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorFixedSize.h
@@ -197,6 +197,23 @@ class TensorFixedSize : public TensorBase<TensorFixedSize<Scalar_, Dimensions_,
     }
 #endif
 
+    template<typename OtherDerived>
+    EIGEN_DEVICE_FUNC
+    EIGEN_STRONG_INLINE TensorFixedSize(const TensorBase<OtherDerived, ReadOnlyAccessors>& other)
+    {
+      typedef TensorAssignOp<TensorFixedSize, const OtherDerived> Assign;
+      Assign assign(*this, other.derived());
+      internal::TensorExecutor<const Assign, DefaultDevice>::run(assign, DefaultDevice());
+    }
+    template<typename OtherDerived>
+    EIGEN_DEVICE_FUNC
+    EIGEN_STRONG_INLINE TensorFixedSize(const TensorBase<OtherDerived, WriteAccessors>& other)
+    {
+      typedef TensorAssignOp<TensorFixedSize, const OtherDerived> Assign;
+      Assign assign(*this, other.derived());
+      internal::TensorExecutor<const Assign, DefaultDevice>::run(assign, DefaultDevice());
+    }
+
     EIGEN_DEVICE_FUNC
     EIGEN_STRONG_INLINE TensorFixedSize& operator=(const TensorFixedSize& other)
     {
diff --git a/unsupported/test/cxx11_tensor_intdiv.cpp b/unsupported/test/cxx11_tensor_intdiv.cpp
index a50356c74..134329034 100644
--- a/unsupported/test/cxx11_tensor_intdiv.cpp
+++ b/unsupported/test/cxx11_tensor_intdiv.cpp
@@ -68,10 +68,23 @@ void test_unsigned_64bit()
 }
 
 
+void test_specific()
+{
+  // A particular combination that exposed a bug in the past.
+  int64_t div = 209715200;
+  int64_t num = 3238002688;
+  Eigen::internal::TensorIntDivisor<int64_t> divider =
+      Eigen::internal::TensorIntDivisor<int64_t>(div);
+  int64_t result = num/div;
+  int64_t result_op = divider.divide(num);
+  VERIFY_IS_EQUAL(result, result_op);
+}
+
 void test_cxx11_tensor_intdiv()
 {
   CALL_SUBTEST_1(test_signed_32bit());
   CALL_SUBTEST_2(test_unsigned_32bit());
   CALL_SUBTEST_3(test_signed_64bit());
   CALL_SUBTEST_4(test_unsigned_64bit());
+  CALL_SUBTEST_5(test_specific());
 }