diff --git a/Eigen/src/Core/ArrayWrapper.h b/Eigen/src/Core/ArrayWrapper.h
index b45395d..b636d88 100644
--- a/Eigen/src/Core/ArrayWrapper.h
+++ b/Eigen/src/Core/ArrayWrapper.h
@@ -65,8 +65,8 @@
     return m_expression.innerStride();
   }
 
-  EIGEN_DEVICE_FUNC inline ScalarWithConstIfNotLvalue* data() { return m_expression.data(); }
-  EIGEN_DEVICE_FUNC inline const Scalar* data() const { return m_expression.data(); }
+  EIGEN_DEVICE_FUNC constexpr ScalarWithConstIfNotLvalue* data() { return m_expression.data(); }
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return m_expression.data(); }
 
   EIGEN_DEVICE_FUNC inline const Scalar& coeffRef(Index rowId, Index colId) const {
     return m_expression.coeffRef(rowId, colId);
@@ -144,8 +144,8 @@
     return m_expression.innerStride();
   }
 
-  EIGEN_DEVICE_FUNC inline ScalarWithConstIfNotLvalue* data() { return m_expression.data(); }
-  EIGEN_DEVICE_FUNC inline const Scalar* data() const { return m_expression.data(); }
+  EIGEN_DEVICE_FUNC constexpr ScalarWithConstIfNotLvalue* data() { return m_expression.data(); }
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return m_expression.data(); }
 
   EIGEN_DEVICE_FUNC inline const Scalar& coeffRef(Index rowId, Index colId) const {
     return m_expression.derived().coeffRef(rowId, colId);
diff --git a/Eigen/src/Core/Block.h b/Eigen/src/Core/Block.h
index 9b16ed2..709264c 100644
--- a/Eigen/src/Core/Block.h
+++ b/Eigen/src/Core/Block.h
@@ -278,7 +278,7 @@
 
 #ifdef EIGEN_PARSED_BY_DOXYGEN
   /** \sa MapBase::data() */
-  EIGEN_DEVICE_FUNC inline const Scalar* data() const;
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const;
   EIGEN_DEVICE_FUNC inline Index innerStride() const;
   EIGEN_DEVICE_FUNC inline Index outerStride() const;
 #endif
diff --git a/Eigen/src/Core/DenseStorage.h b/Eigen/src/Core/DenseStorage.h
index f616939..49c4099 100644
--- a/Eigen/src/Core/DenseStorage.h
+++ b/Eigen/src/Core/DenseStorage.h
@@ -258,8 +258,8 @@
     m_cols = cols;
     eigen_assert(m_rows * m_cols == 0 && "The number of rows times columns must equal the storage size.");
   }
-  EIGEN_DEVICE_FUNC const T* data() const { return nullptr; }
-  EIGEN_DEVICE_FUNC T* data() { return nullptr; }
+  EIGEN_DEVICE_FUNC constexpr const T* data() const { return nullptr; }
+  EIGEN_DEVICE_FUNC constexpr T* data() { return nullptr; }
 };
 
 template <typename T, int Rows_, int Options_>
@@ -288,8 +288,8 @@
     m_cols = cols;
     eigen_assert(Rows_ * m_cols == 0 && "The number of rows times columns must equal the storage size.");
   }
-  EIGEN_DEVICE_FUNC const T* data() const { return nullptr; }
-  EIGEN_DEVICE_FUNC T* data() { return nullptr; }
+  EIGEN_DEVICE_FUNC constexpr const T* data() const { return nullptr; }
+  EIGEN_DEVICE_FUNC constexpr T* data() { return nullptr; }
 };
 
 template <typename T, int Cols_, int Options_>
@@ -318,8 +318,8 @@
     m_rows = rows;
     eigen_assert(m_rows * Cols_ == 0 && "The number of rows times columns must equal the storage size.");
   }
-  EIGEN_DEVICE_FUNC const T* data() const { return nullptr; }
-  EIGEN_DEVICE_FUNC T* data() { return nullptr; }
+  EIGEN_DEVICE_FUNC constexpr const T* data() const { return nullptr; }
+  EIGEN_DEVICE_FUNC constexpr T* data() { return nullptr; }
 };
 
 // dynamic-size matrix with fixed-size storage
@@ -507,8 +507,8 @@
     m_rows = rows;
     m_cols = cols;
   }
-  EIGEN_DEVICE_FUNC const T* data() const { return m_data; }
-  EIGEN_DEVICE_FUNC T* data() { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr const T* data() const { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr T* data() { return m_data; }
 };
 
 // matrix with dynamic width and fixed height (so that matrix has dynamic size).
@@ -574,8 +574,8 @@
     }
     m_cols = cols;
   }
-  EIGEN_DEVICE_FUNC const T* data() const { return m_data; }
-  EIGEN_DEVICE_FUNC T* data() { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr const T* data() const { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr T* data() { return m_data; }
 };
 
 // matrix with dynamic height and fixed width (so that matrix has dynamic size).
@@ -641,8 +641,8 @@
     }
     m_rows = rows;
   }
-  EIGEN_DEVICE_FUNC const T* data() const { return m_data; }
-  EIGEN_DEVICE_FUNC T* data() { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr const T* data() const { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr T* data() { return m_data; }
 };
 
 }  // end namespace Eigen
diff --git a/Eigen/src/Core/GeneralProduct.h b/Eigen/src/Core/GeneralProduct.h
index b7ae44f..dc12481 100644
--- a/Eigen/src/Core/GeneralProduct.h
+++ b/Eigen/src/Core/GeneralProduct.h
@@ -229,7 +229,7 @@
 
 template <typename Scalar, int Size, int MaxSize>
 struct gemv_static_vector_if<Scalar, Size, MaxSize, false> {
-  EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC Scalar* data() {
+  EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC constexpr Scalar* data() {
     eigen_internal_assert(false && "should never be called");
     return 0;
   }
@@ -237,19 +237,19 @@
 
 template <typename Scalar, int Size>
 struct gemv_static_vector_if<Scalar, Size, Dynamic, true> {
-  EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC Scalar* data() { return 0; }
+  EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC constexpr Scalar* data() { return 0; }
 };
 
 template <typename Scalar, int Size, int MaxSize>
 struct gemv_static_vector_if<Scalar, Size, MaxSize, true> {
 #if EIGEN_MAX_STATIC_ALIGN_BYTES != 0
   internal::plain_array<Scalar, internal::min_size_prefer_fixed(Size, MaxSize), 0, AlignedMax> m_data;
-  EIGEN_STRONG_INLINE Scalar* data() { return m_data.array; }
+  EIGEN_STRONG_INLINE constexpr Scalar* data() { return m_data.array; }
 #else
   // Some architectures cannot align on the stack,
   // => let's manually enforce alignment by allocating more data and return the address of the first aligned element.
   internal::plain_array<Scalar, internal::min_size_prefer_fixed(Size, MaxSize) + EIGEN_MAX_ALIGN_BYTES, 0> m_data;
-  EIGEN_STRONG_INLINE Scalar* data() {
+  EIGEN_STRONG_INLINE constexpr Scalar* data() {
     return reinterpret_cast<Scalar*>((std::uintptr_t(m_data.array) & ~(std::size_t(EIGEN_MAX_ALIGN_BYTES - 1))) +
                                      EIGEN_MAX_ALIGN_BYTES);
   }
diff --git a/Eigen/src/Core/MapBase.h b/Eigen/src/Core/MapBase.h
index da95b5c..1e83fdf 100644
--- a/Eigen/src/Core/MapBase.h
+++ b/Eigen/src/Core/MapBase.h
@@ -94,7 +94,7 @@
    *
    * \sa innerStride(), outerStride()
    */
-  EIGEN_DEVICE_FUNC inline const Scalar* data() const { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return m_data; }
 
   /** \copydoc PlainObjectBase::coeff(Index,Index) const */
   EIGEN_DEVICE_FUNC inline const Scalar& coeff(Index rowId, Index colId) const {
@@ -233,8 +233,8 @@
 
   typedef std::conditional_t<internal::is_lvalue<Derived>::value, Scalar, const Scalar> ScalarWithConstIfNotLvalue;
 
-  EIGEN_DEVICE_FUNC inline const Scalar* data() const { return this->m_data; }
-  EIGEN_DEVICE_FUNC inline ScalarWithConstIfNotLvalue* data() {
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return this->m_data; }
+  EIGEN_DEVICE_FUNC constexpr ScalarWithConstIfNotLvalue* data() {
     return this->m_data;
   }  // no const-cast here so non-const-correct code will give a compile error
 
diff --git a/Eigen/src/Core/PlainObjectBase.h b/Eigen/src/Core/PlainObjectBase.h
index df90318..62195f4 100644
--- a/Eigen/src/Core/PlainObjectBase.h
+++ b/Eigen/src/Core/PlainObjectBase.h
@@ -270,10 +270,10 @@
   }
 
   /** \returns a const pointer to the data array of this matrix */
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar* data() const { return m_storage.data(); }
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return m_storage.data(); }
 
   /** \returns a pointer to the data array of this matrix */
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Scalar* data() { return m_storage.data(); }
+  EIGEN_DEVICE_FUNC constexpr Scalar* data() { return m_storage.data(); }
 
   /** Resizes \c *this to a \a rows x \a cols matrix.
    *
diff --git a/Eigen/src/Core/Reshaped.h b/Eigen/src/Core/Reshaped.h
index b881dd6..4b34e16 100644
--- a/Eigen/src/Core/Reshaped.h
+++ b/Eigen/src/Core/Reshaped.h
@@ -173,7 +173,7 @@
 
 #ifdef EIGEN_PARSED_BY_DOXYGEN
   /** \sa MapBase::data() */
-  EIGEN_DEVICE_FUNC inline const Scalar* data() const;
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const;
   EIGEN_DEVICE_FUNC inline Index innerStride() const;
   EIGEN_DEVICE_FUNC inline Index outerStride() const;
 #endif
diff --git a/Eigen/src/Core/Stride.h b/Eigen/src/Core/Stride.h
index a8fdeaf..14b025c 100644
--- a/Eigen/src/Core/Stride.h
+++ b/Eigen/src/Core/Stride.h
@@ -70,6 +70,13 @@
   /** Copy constructor */
   EIGEN_DEVICE_FUNC Stride(const Stride& other) : m_outer(other.outer()), m_inner(other.inner()) {}
 
+  /** Copy assignment operator */
+  EIGEN_DEVICE_FUNC Stride& operator=(const Stride& other) {
+    m_outer.setValue(other.outer());
+    m_inner.setValue(other.inner());
+    return *this;
+  }
+
   /** \returns the outer stride */
   EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR inline Index outer() const { return m_outer.value(); }
   /** \returns the inner stride */
diff --git a/Eigen/src/Core/Transpose.h b/Eigen/src/Core/Transpose.h
index 1cc7a28..89e3d95 100644
--- a/Eigen/src/Core/Transpose.h
+++ b/Eigen/src/Core/Transpose.h
@@ -119,10 +119,12 @@
 
   typedef std::conditional_t<internal::is_lvalue<MatrixType>::value, Scalar, const Scalar> ScalarWithConstIfNotLvalue;
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE ScalarWithConstIfNotLvalue* data() {
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr ScalarWithConstIfNotLvalue* data() {
     return derived().nestedExpression().data();
   }
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar* data() const { return derived().nestedExpression().data(); }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr const Scalar* data() const {
+    return derived().nestedExpression().data();
+  }
 
   // FIXME: shall we keep the const version of coeffRef?
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar& coeffRef(Index rowId, Index colId) const {
diff --git a/Eigen/src/Core/util/BlasUtil.h b/Eigen/src/Core/util/BlasUtil.h
index c2994b2..19d9917 100644
--- a/Eigen/src/Core/util/BlasUtil.h
+++ b/Eigen/src/Core/util/BlasUtil.h
@@ -241,7 +241,7 @@
 
   EIGEN_DEVICE_FUNC const Index stride() const { return m_stride; }
   EIGEN_DEVICE_FUNC const Index incr() const { return 1; }
-  EIGEN_DEVICE_FUNC const Scalar* data() const { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return m_data; }
 
   EIGEN_DEVICE_FUNC Index firstAligned(Index size) const {
     if (std::uintptr_t(m_data) % sizeof(Scalar)) {
@@ -430,7 +430,7 @@
 
   EIGEN_DEVICE_FUNC const Index stride() const { return m_stride; }
   EIGEN_DEVICE_FUNC const Index incr() const { return m_incr.value(); }
-  EIGEN_DEVICE_FUNC Scalar* data() const { return m_data; }
+  EIGEN_DEVICE_FUNC constexpr Scalar* data() const { return m_data; }
 
  protected:
   Scalar* EIGEN_RESTRICT m_data;
diff --git a/Eigen/src/Core/util/MaxSizeVector.h b/Eigen/src/Core/util/MaxSizeVector.h
index 2f1e3d3..54b556d 100644
--- a/Eigen/src/Core/util/MaxSizeVector.h
+++ b/Eigen/src/Core/util/MaxSizeVector.h
@@ -116,17 +116,17 @@
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool empty() const { return size_ == 0; }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T* data() { return data_; }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr T* data() { return data_; }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T* data() const { return data_; }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr const T* data() const { return data_; }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T* begin() { return data_; }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr T* begin() { return data_; }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T* end() { return data_ + size_; }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr T* end() { return data_ + size_; }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T* begin() const { return data_; }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr const T* begin() const { return data_; }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T* end() const { return data_ + size_; }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr const T* end() const { return data_ + size_; }
 
  private:
   size_t reserve_;
diff --git a/Eigen/src/Geometry/Transform.h b/Eigen/src/Geometry/Transform.h
index fd3fc58..b1a9f21 100644
--- a/Eigen/src/Geometry/Transform.h
+++ b/Eigen/src/Geometry/Transform.h
@@ -588,9 +588,9 @@
   EIGEN_DEVICE_FUNC inline Transform inverse(TransformTraits traits = (TransformTraits)Mode) const;
 
   /** \returns a const pointer to the column major internal matrix */
-  EIGEN_DEVICE_FUNC const Scalar* data() const { return m_matrix.data(); }
+  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return m_matrix.data(); }
   /** \returns a non-const pointer to the column major internal matrix */
-  EIGEN_DEVICE_FUNC Scalar* data() { return m_matrix.data(); }
+  EIGEN_DEVICE_FUNC constexpr Scalar* data() { return m_matrix.data(); }
 
   /** \returns \c *this with scalar type casted to \a NewScalarType
    *
diff --git a/Eigen/src/SparseCore/SparseMatrix.h b/Eigen/src/SparseCore/SparseMatrix.h
index 24ebb7c..16ee8da 100644
--- a/Eigen/src/SparseCore/SparseMatrix.h
+++ b/Eigen/src/SparseCore/SparseMatrix.h
@@ -202,9 +202,9 @@
   inline StorageIndex* innerNonZeroPtr() { return m_innerNonZeros; }
 
   /** \internal */
-  inline Storage& data() { return m_data; }
+  constexpr Storage& data() { return m_data; }
   /** \internal */
-  inline const Storage& data() const { return m_data; }
+  constexpr const Storage& data() const { return m_data; }
 
   /** \returns the value of the matrix at position \a i, \a j
    * This function returns Scalar(0) if the element is an explicit \em zero */
diff --git a/Eigen/src/SparseCore/SparseVector.h b/Eigen/src/SparseCore/SparseVector.h
index 6b1816b..58ebb1b 100644
--- a/Eigen/src/SparseCore/SparseVector.h
+++ b/Eigen/src/SparseCore/SparseVector.h
@@ -90,9 +90,9 @@
   inline StorageIndex* innerNonZeroPtr() { return 0; }
 
   /** \internal */
-  inline Storage& data() { return m_data; }
+  constexpr Storage& data() { return m_data; }
   /** \internal */
-  inline const Storage& data() const { return m_data; }
+  constexpr const Storage& data() const { return m_data; }
 
   inline Scalar coeff(Index row, Index col) const {
     eigen_assert(IsColVector ? (col == 0 && row >= 0 && row < m_size) : (row == 0 && col >= 0 && col < m_size));