diff --git a/Eigen/src/Core/DenseStorage.h b/Eigen/src/Core/DenseStorage.h
index d27fb7bfb..39507ff37 100644
--- a/Eigen/src/Core/DenseStorage.h
+++ b/Eigen/src/Core/DenseStorage.h
@@ -198,16 +198,16 @@ template<typename T, int _Options> class DenseStorage<T, Dynamic, Dynamic, Dynam
     inline DenseStorage(internal::constructor_without_unaligned_array_assert)
        : m_data(0), m_rows(0), m_cols(0) {}
     inline DenseStorage(DenseIndex size, DenseIndex rows, DenseIndex cols)
-      : m_data(internal::conditional_aligned_new<T,(_Options&DontAlign)==0>(size)), m_rows(rows), m_cols(cols) 
+      : m_data(internal::conditional_aligned_new_auto<T,(_Options&DontAlign)==0>(size)), m_rows(rows), m_cols(cols) 
     { EIGEN_INTERNAL_DENSE_STORAGE_CTOR_PLUGIN }
-    inline ~DenseStorage() { internal::conditional_aligned_delete<T,(_Options&DontAlign)==0>(m_data, m_rows*m_cols); }
+    inline ~DenseStorage() { internal::conditional_aligned_delete_auto<T,(_Options&DontAlign)==0>(m_data, m_rows*m_cols); }
     inline void swap(DenseStorage& other)
     { std::swap(m_data,other.m_data); std::swap(m_rows,other.m_rows); std::swap(m_cols,other.m_cols); }
     inline DenseIndex rows(void) const {return m_rows;}
     inline DenseIndex cols(void) const {return m_cols;}
     inline void conservativeResize(DenseIndex size, DenseIndex rows, DenseIndex cols)
     {
-      m_data = internal::conditional_aligned_realloc_new<T,(_Options&DontAlign)==0>(m_data, size, m_rows*m_cols);
+      m_data = internal::conditional_aligned_realloc_new_auto<T,(_Options&DontAlign)==0>(m_data, size, m_rows*m_cols);
       m_rows = rows;
       m_cols = cols;
     }
@@ -215,9 +215,9 @@ template<typename T, int _Options> class DenseStorage<T, Dynamic, Dynamic, Dynam
     {
       if(size != m_rows*m_cols)
       {
-        internal::conditional_aligned_delete<T,(_Options&DontAlign)==0>(m_data, m_rows*m_cols);
+        internal::conditional_aligned_delete_auto<T,(_Options&DontAlign)==0>(m_data, m_rows*m_cols);
         if (size)
-          m_data = internal::conditional_aligned_new<T,(_Options&DontAlign)==0>(size);
+          m_data = internal::conditional_aligned_new_auto<T,(_Options&DontAlign)==0>(size);
         else
           m_data = 0;
         EIGEN_INTERNAL_DENSE_STORAGE_CTOR_PLUGIN
@@ -237,24 +237,24 @@ template<typename T, int _Rows, int _Options> class DenseStorage<T, Dynamic, _Ro
   public:
     inline explicit DenseStorage() : m_data(0), m_cols(0) {}
     inline DenseStorage(internal::constructor_without_unaligned_array_assert) : m_data(0), m_cols(0) {}
-    inline DenseStorage(DenseIndex size, DenseIndex, DenseIndex cols) : m_data(internal::conditional_aligned_new<T,(_Options&DontAlign)==0>(size)), m_cols(cols)
+    inline DenseStorage(DenseIndex size, DenseIndex, DenseIndex cols) : m_data(internal::conditional_aligned_new_auto<T,(_Options&DontAlign)==0>(size)), m_cols(cols)
     { EIGEN_INTERNAL_DENSE_STORAGE_CTOR_PLUGIN }
-    inline ~DenseStorage() { internal::conditional_aligned_delete<T,(_Options&DontAlign)==0>(m_data, _Rows*m_cols); }
+    inline ~DenseStorage() { internal::conditional_aligned_delete_auto<T,(_Options&DontAlign)==0>(m_data, _Rows*m_cols); }
     inline void swap(DenseStorage& other) { std::swap(m_data,other.m_data); std::swap(m_cols,other.m_cols); }
     inline static DenseIndex rows(void) {return _Rows;}
     inline DenseIndex cols(void) const {return m_cols;}
     inline void conservativeResize(DenseIndex size, DenseIndex, DenseIndex cols)
     {
-      m_data = internal::conditional_aligned_realloc_new<T,(_Options&DontAlign)==0>(m_data, size, _Rows*m_cols);
+      m_data = internal::conditional_aligned_realloc_new_auto<T,(_Options&DontAlign)==0>(m_data, size, _Rows*m_cols);
       m_cols = cols;
     }
     EIGEN_STRONG_INLINE void resize(DenseIndex size, DenseIndex, DenseIndex cols)
     {
       if(size != _Rows*m_cols)
       {
-        internal::conditional_aligned_delete<T,(_Options&DontAlign)==0>(m_data, _Rows*m_cols);
+        internal::conditional_aligned_delete_auto<T,(_Options&DontAlign)==0>(m_data, _Rows*m_cols);
         if (size)
-          m_data = internal::conditional_aligned_new<T,(_Options&DontAlign)==0>(size);
+          m_data = internal::conditional_aligned_new_auto<T,(_Options&DontAlign)==0>(size);
         else
           m_data = 0;
         EIGEN_INTERNAL_DENSE_STORAGE_CTOR_PLUGIN
@@ -273,24 +273,24 @@ template<typename T, int _Cols, int _Options> class DenseStorage<T, Dynamic, Dyn
   public:
     inline explicit DenseStorage() : m_data(0), m_rows(0) {}
     inline DenseStorage(internal::constructor_without_unaligned_array_assert) : m_data(0), m_rows(0) {}
-    inline DenseStorage(DenseIndex size, DenseIndex rows, DenseIndex) : m_data(internal::conditional_aligned_new<T,(_Options&DontAlign)==0>(size)), m_rows(rows)
+    inline DenseStorage(DenseIndex size, DenseIndex rows, DenseIndex) : m_data(internal::conditional_aligned_new_auto<T,(_Options&DontAlign)==0>(size)), m_rows(rows)
     { EIGEN_INTERNAL_DENSE_STORAGE_CTOR_PLUGIN }
-    inline ~DenseStorage() { internal::conditional_aligned_delete<T,(_Options&DontAlign)==0>(m_data, _Cols*m_rows); }
+    inline ~DenseStorage() { internal::conditional_aligned_delete_auto<T,(_Options&DontAlign)==0>(m_data, _Cols*m_rows); }
     inline void swap(DenseStorage& other) { std::swap(m_data,other.m_data); std::swap(m_rows,other.m_rows); }
     inline DenseIndex rows(void) const {return m_rows;}
     inline static DenseIndex cols(void) {return _Cols;}
     inline void conservativeResize(DenseIndex size, DenseIndex rows, DenseIndex)
     {
-      m_data = internal::conditional_aligned_realloc_new<T,(_Options&DontAlign)==0>(m_data, size, m_rows*_Cols);
+      m_data = internal::conditional_aligned_realloc_new_auto<T,(_Options&DontAlign)==0>(m_data, size, m_rows*_Cols);
       m_rows = rows;
     }
     EIGEN_STRONG_INLINE void resize(DenseIndex size, DenseIndex rows, DenseIndex)
     {
       if(size != m_rows*_Cols)
       {
-        internal::conditional_aligned_delete<T,(_Options&DontAlign)==0>(m_data, _Cols*m_rows);
+        internal::conditional_aligned_delete_auto<T,(_Options&DontAlign)==0>(m_data, _Cols*m_rows);
         if (size)
-          m_data = internal::conditional_aligned_new<T,(_Options&DontAlign)==0>(size);
+          m_data = internal::conditional_aligned_new_auto<T,(_Options&DontAlign)==0>(size);
         else
           m_data = 0;
         EIGEN_INTERNAL_DENSE_STORAGE_CTOR_PLUGIN
diff --git a/Eigen/src/Core/NumTraits.h b/Eigen/src/Core/NumTraits.h
index 13dae85a4..5c7762dae 100644
--- a/Eigen/src/Core/NumTraits.h
+++ b/Eigen/src/Core/NumTraits.h
@@ -53,6 +53,8 @@
   *     to by move / add / mul instructions respectively, assuming the data is already stored in CPU registers.
   *     Stay vague here. No need to do architecture-specific stuff.
   * \li An enum value \a IsSigned. It is equal to \c 1 if \a T is a signed type and to 0 if \a T is unsigned.
+  * \li An enum value \a RequireInitialization. It is equal to \c 1 if the constructor of the numeric type \a T must
+  *     be called, and to 0 if it is safe not to call it. Default is 0 if \a T is an arithmetic type, and 1 otherwise.
   * \li An epsilon() function which, unlike std::numeric_limits::epsilon(), returns a \a Real instead of a \a T.
   * \li A dummy_precision() function returning a weak epsilon value. It is mainly used as a default
   *     value by the fuzzy comparison operators.
@@ -65,6 +67,7 @@ template<typename T> struct GenericNumTraits
     IsInteger = std::numeric_limits<T>::is_integer,
     IsSigned = std::numeric_limits<T>::is_signed,
     IsComplex = 0,
+    RequireInitialization = internal::is_arithmetic<T>::value ? 0 : 1,
     ReadCost = 1,
     AddCost = 1,
     MulCost = 1
@@ -121,6 +124,7 @@ template<typename _Real> struct NumTraits<std::complex<_Real> >
   typedef _Real Real;
   enum {
     IsComplex = 1,
+    RequireInitialization = NumTraits<_Real>::RequireInitialization,
     ReadCost = 2 * NumTraits<_Real>::ReadCost,
     AddCost = 2 * NumTraits<Real>::AddCost,
     MulCost = 4 * NumTraits<Real>::MulCost + 2 * NumTraits<Real>::AddCost
@@ -144,6 +148,7 @@ struct NumTraits<Array<Scalar, Rows, Cols, Options, MaxRows, MaxCols> >
     IsComplex = NumTraits<Scalar>::IsComplex,
     IsInteger = NumTraits<Scalar>::IsInteger,
     IsSigned  = NumTraits<Scalar>::IsSigned,
+    RequireInitialization = 1,
     ReadCost = ArrayType::SizeAtCompileTime==Dynamic ? Dynamic : ArrayType::SizeAtCompileTime * NumTraits<Scalar>::ReadCost,
     AddCost  = ArrayType::SizeAtCompileTime==Dynamic ? Dynamic : ArrayType::SizeAtCompileTime * NumTraits<Scalar>::AddCost,
     MulCost  = ArrayType::SizeAtCompileTime==Dynamic ? Dynamic : ArrayType::SizeAtCompileTime * NumTraits<Scalar>::MulCost
diff --git a/Eigen/src/Core/util/Memory.h b/Eigen/src/Core/util/Memory.h
index 9f95d5bc7..558486418 100644
--- a/Eigen/src/Core/util/Memory.h
+++ b/Eigen/src/Core/util/Memory.h
@@ -369,6 +369,30 @@ template<typename T, bool Align> inline T* conditional_aligned_realloc_new(T* pt
   return result;
 }
 
+
+template<typename T, bool Align> inline T* conditional_aligned_new_auto(size_t size)
+{
+  T *result = reinterpret_cast<T*>(conditional_aligned_malloc<Align>(sizeof(T)*size));
+  if(NumTraits<T>::RequireInitialization)
+    construct_elements_of_array(result, size);
+  return result;
+}
+
+template<typename T, bool Align> inline T* conditional_aligned_realloc_new_auto(T* pts, size_t new_size, size_t old_size)
+{
+  T *result = reinterpret_cast<T*>(conditional_aligned_realloc<Align>(reinterpret_cast<void*>(pts), sizeof(T)*new_size, sizeof(T)*old_size));
+  if (NumTraits<T>::RequireInitialization && (new_size > old_size))
+    construct_elements_of_array(result+old_size, new_size-old_size);
+  return result;
+}
+
+template<typename T, bool Align> inline void conditional_aligned_delete_auto(T *ptr, size_t size)
+{
+  if(NumTraits<T>::RequireInitialization)
+    destruct_elements_of_array<T>(ptr, size);
+  conditional_aligned_free<Align>(ptr);
+}
+
 /****************************************************************************/
 
 /** \internal Returns the index of the first element of the array that is well aligned for vectorization.
diff --git a/unsupported/Eigen/MPRealSupport b/unsupported/Eigen/MPRealSupport
index 37e75b2c7..6bded0c2c 100644
--- a/unsupported/Eigen/MPRealSupport
+++ b/unsupported/Eigen/MPRealSupport
@@ -80,6 +80,7 @@ int main()
       IsInteger = 0,
       IsSigned = 1,
       IsComplex = 0,
+      RequireInitialization = 1,
       ReadCost = 10,
       AddCost = 10,
       MulCost = 40