diff --git a/include/boost/multiprecision/complex_adaptor.hpp b/include/boost/multiprecision/complex_adaptor.hpp
index 62bb0fc2..8ba050f6 100644
--- a/include/boost/multiprecision/complex_adaptor.hpp
+++ b/include/boost/multiprecision/complex_adaptor.hpp
@@ -77,6 +77,18 @@ struct complex_adaptor
       m_real = val.real();
       m_imag = val.imag();
    }
+   template <class T, class U>
+   complex_adaptor(const T& a, const U& b, typename std::enable_if<std::is_constructible<Backend, T const&>::value&& std::is_constructible<Backend, U const&>::value>::type const* = nullptr)
+      : m_real(a), m_imag(b) {}
+   template <class T, class U>
+   complex_adaptor(T&& a, const U& b, typename std::enable_if<std::is_constructible<Backend, T>::value&& std::is_constructible<Backend, U>::value>::type const* = nullptr)
+      : m_real(static_cast<T&&>(a)), m_imag(b) {}
+   template <class T, class U>
+   complex_adaptor(T&& a, U&& b, typename std::enable_if<std::is_constructible<Backend, T>::value&& std::is_constructible<Backend, U>::value>::type const* = nullptr)
+      : m_real(static_cast<T&&>(a)), m_imag(static_cast<U&&>(b)) {}
+   template <class T, class U>
+   complex_adaptor(const T& a, U&& b, typename std::enable_if<std::is_constructible<Backend, T>::value&& std::is_constructible<Backend, U>::value>::type const* = nullptr)
+      : m_real(a), m_imag(static_cast<U&&>(b)) {}
 
    complex_adaptor& operator=(const complex_adaptor& o)
    {
diff --git a/include/boost/multiprecision/detail/et_ops.hpp b/include/boost/multiprecision/detail/et_ops.hpp
index 7a9a4c92..2d881fb5 100644
--- a/include/boost/multiprecision/detail/et_ops.hpp
+++ b/include/boost/multiprecision/detail/et_ops.hpp
@@ -142,18 +142,21 @@ operator+(const number<B, ET>& a, const detail::expression<tag, Arg1, Arg2, Arg3
 }
 
 template <class B, expression_template_option ET, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::plus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if< 
+   std::is_same<typename detail::expression<detail::plus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET> >::value,
+   typename detail::expression<detail::plus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
 operator+(number<B, ET>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::plus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET> >::value)
-   {
-      a += b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-   {
-      return detail::expression<detail::plus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
-   }
+   a += b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, expression_template_option ET, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if< 
+   !std::is_same<typename detail::expression<detail::plus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET> >::value,
+   typename detail::expression<detail::plus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
+operator+(number<B, ET>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::plus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
@@ -164,18 +167,21 @@ operator+(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, const number
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::plus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if< 
+   std::is_same<typename detail::expression<detail::plus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::plus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type>::type
 operator+(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::plus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value)
-   {
-      b += a;
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-   {
-      return detail::expression<detail::plus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >(a, b);
-   }
+   b += a;
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if< 
+   !std::is_same<typename detail::expression<detail::plus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::plus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type>::type
+operator+(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
+{
+   return detail::expression<detail::plus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >(a, b);
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class tag2, class Arg1b, class Arg2b, class Arg3b, class Arg4b>
@@ -221,18 +227,21 @@ operator+(const number<B, ET>& a, const detail::expression<detail::multiply_imme
 }
 
 template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type>::type
 operator+(number<B, ET>&& a, const detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type, number<B, ET>>::value)
-   {
-      a += b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-   {
-      return detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >(b.left(), b.right(), a);
-   }
+   a += b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type>::type
+operator+(number<B, ET>&& a, const detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >(b.left(), b.right(), a);
 }
 
 template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
@@ -243,18 +252,21 @@ operator+(const detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3
 }
 
 template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type>::type
 operator+(const detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type, number<B, ET>>::value)
-   {
-      b += a;
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-   {
-      return detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >(a.left(), a.right(), b);
-   }
+   b += a;
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >::result_type>::type
+operator+(const detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
+{
+   return detail::expression<detail::multiply_add, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >(a.left(), a.right(), b);
 }
 
 //
@@ -282,18 +294,21 @@ operator-(const number<B, ET>& a, const detail::expression<detail::multiply_imme
 }
 
 template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::negate, detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> > >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> > >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> > >::result_type>::type
 operator-(number<B, ET>&& a, const detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> > >::result_type, number<B, ET>>::value)
-   {
-      a -= b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-   {
-      return detail::expression<detail::negate, detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> > >(detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >(b.left(), b.right(), a));
-   }
+   a -= b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> > >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> > >::result_type>::type
+operator-(number<B, ET>&& a, const detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::negate, detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> > >(detail::expression<detail::multiply_subtract, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::left_type, typename detail::expression<detail::multiply_immediates, Arg1, Arg2, Arg3, Arg4>::right_type, number<B, ET> >(b.left(), b.right(), a));
 }
 
 template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
@@ -321,18 +336,21 @@ operator+(const number<B, ET>& a, const detail::expression<detail::negate, Arg1,
 }
 
 template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type>::type
 operator+(number<B, ET>&& a, const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value)
-   {
-      a -= b.left_ref();
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-   {
-      return detail::expression<detail::minus, number<B, ET>, Arg1>(a, b.left_ref());
-   }
+   a -= b.left_ref();
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type>::type
+operator+(number<B, ET>&& a, const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::minus, number<B, ET>, Arg1>(a, b.left_ref());
 }
 
 template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
@@ -343,18 +361,21 @@ operator+(const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& a, c
 }
 
 template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type>::type
 operator+(const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value)
-   {
-      b -= a.left_ref();
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-   {
-      return detail::expression<detail::minus, number<B, ET>, Arg1>(b, a.left_ref());
-   }
+   b -= a.left_ref();
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::minus, number<B, ET>, Arg1>::result_type>::type
+operator+(const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
+{
+   return detail::expression<detail::minus, number<B, ET>, Arg1>(b, a.left_ref());
 }
 
 template <class B>
@@ -506,18 +527,21 @@ operator-(const number<B, ET>& a, const detail::expression<tag, Arg1, Arg2, Arg3
 }
 
 template <class B, expression_template_option ET, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::minus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::minus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::minus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
 operator-(number<B, ET>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::minus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value)
-   {
-      a -= b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-   {
-      return detail::expression<detail::minus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
-   }
+   a -= b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, expression_template_option ET, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::minus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::minus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
+operator-(number<B, ET>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::minus, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
@@ -528,19 +552,22 @@ operator-(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, const number
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::minus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::minus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::minus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type>::type
 operator-(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::minus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value)
-   {
-      b -= a;
-      b.backend().negate();
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-   {
-      return detail::expression<detail::minus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >(a, b);
-   }
+   b -= a;
+   b.backend().negate();
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::minus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::minus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type>::type
+operator-(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
+{
+   return detail::expression<detail::minus, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >(a, b);
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class tag2, class Arg1b, class Arg2b, class Arg3b, class Arg4b>
@@ -572,16 +599,21 @@ operator-(const number<B, ET>& a, const detail::expression<detail::negate, Arg1,
 }
 
 template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::plus, number<B, ET>, Arg1>::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::plus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::plus, number<B, ET>, Arg1>::result_type>::type
 operator-(number<B, ET>&& a, const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::plus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value)
-   {
-      a += b.left_ref();
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-      return detail::expression<detail::plus, number<B, ET>, Arg1>(a, b.left_ref());
+   a += b.left_ref();
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::plus, number<B, ET>, Arg1>::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::plus, number<B, ET>, Arg1>::result_type>::type
+operator-(number<B, ET>&& a, const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::plus, number<B, ET>, Arg1>(a, b.left_ref());
 }
 
 template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
@@ -593,17 +625,22 @@ operator-(const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& a, c
 }
 
 template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::negate, detail::expression<detail::plus, number<B, ET>, Arg1> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::negate, detail::expression<detail::plus, number<B, ET>, Arg1> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::plus, number<B, ET>, Arg1> >::result_type>::type
 operator-(const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::negate, detail::expression<detail::plus, number<B, ET>, Arg1> >::result_type, number<B, ET>>::value)
-   {
-      b += a.left_ref();
-      b.backend().negate();
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-      return detail::expression<detail::negate, detail::expression<detail::plus, number<B, ET>, Arg1> >(detail::expression<detail::plus, number<B, ET>, Arg1>(b, a.left_ref()));
+   b += a.left_ref();
+   b.backend().negate();
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::negate, detail::expression<detail::plus, number<B, ET>, Arg1> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::plus, number<B, ET>, Arg1> >::result_type>::type
+operator-(const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
+{
+   return detail::expression<detail::negate, detail::expression<detail::plus, number<B, ET>, Arg1> >(detail::expression<detail::plus, number<B, ET>, Arg1>(b, a.left_ref()));
 }
 
 template <class B>
@@ -631,18 +668,23 @@ operator-(const detail::expression<detail::negate, number<B, et_on> >& a, const
 }
 
 template <class B>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::negate, detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> > >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::negate, detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> > >::result_type>::type
 operator-(const detail::expression<detail::negate, number<B, et_on> >& a, number<B, et_on>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::negate, detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value)
-   {
-      using default_ops::eval_add;
-      eval_add(b.backend(), a.left_ref().backend());
-      b.backend().negate();
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-      return detail::expression<detail::negate, detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> > >(
+   using default_ops::eval_add;
+   eval_add(b.backend(), a.left_ref().backend());
+   b.backend().negate();
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class B>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::negate, detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> > >::result_type>::type
+operator-(const detail::expression<detail::negate, number<B, et_on> >& a, number<B, et_on>&& b)
+{
+   return detail::expression<detail::negate, detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> > >(
          detail::expression<detail::add_immediates, number<B, et_on>, number<B, et_on> >(b, a.left_ref()));
 }
 
@@ -761,16 +803,21 @@ operator*(const number<B, ET>& a, const detail::expression<tag, Arg1, Arg2, Arg3
 }
 
 template <class B, expression_template_option ET, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::multiplies, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::multiplies, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::multiplies, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
 operator*(number<B, ET>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::multiplies, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value)
-   {
-      a *= b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-      return detail::expression<detail::multiplies, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
+   a *= b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, expression_template_option ET, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::multiplies, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::multiplies, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
+operator*(number<B, ET>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::multiplies, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
@@ -781,16 +828,21 @@ operator*(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, const number
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::multiplies, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::multiplies, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::multiplies, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type>::type
 operator*(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::multiplies, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value)
-   {
-      b *= a;
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-      return detail::expression<detail::multiplies, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >(a, b);
+   b *= a;
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::multiplies, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::multiplies, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >::result_type>::type
+operator*(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, ET>&& b)
+{
+   return detail::expression<detail::multiplies, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >(a, b);
 }
 
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class tag2, class Arg1b, class Arg2b, class Arg3b, class Arg4b>
@@ -855,17 +907,22 @@ operator*(const number<B, et_on>& a, const detail::expression<detail::negate, nu
 }
 
 template <class B>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type>::type
 operator*(number<B, et_on>&& a, const detail::expression<detail::negate, number<B, et_on> >& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value)
-   {
-      a *= b.left_ref();
-      a.backend().negate();
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-      return detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >(
+   a *= b.left_ref();
+   a.backend().negate();
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type>::type
+operator*(number<B, et_on>&& a, const detail::expression<detail::negate, number<B, et_on> >& b)
+{
+   return detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >(
          detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> >(a, b.left_ref()));
 }
 
@@ -878,17 +935,22 @@ operator*(const detail::expression<detail::negate, number<B, et_on> >& a, const
 }
 
 template <class B>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type>::type
 operator*(const detail::expression<detail::negate, number<B, et_on> >& a, number<B, et_on>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value)
-   {
-      b *= a.left_ref();
-      b.backend().negate();
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-      return detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >(
+   b *= a.left_ref();
+   b.backend().negate();
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class B>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type, number<B, et_on>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >::result_type>::type
+operator*(const detail::expression<detail::negate, number<B, et_on> >& a, number<B, et_on>&& b)
+{
+   return detail::expression<detail::negate, detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> > >(
          detail::expression<detail::multiply_immediates, number<B, et_on>, number<B, et_on> >(b, a.left_ref()));
 }
 
@@ -1002,16 +1064,21 @@ operator/(const number<B, ET>& a, const detail::expression<tag, Arg1, Arg2, Arg3
    return detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class B, expression_template_option ET, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
 operator/(number<B, ET>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value)
-   {
-      a /= b;
-      return static_cast<number<B, ET>&&>(a);
-   }
-   else
-      return detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
+   a /= b;
+   return static_cast<number<B, ET>&&>(a);
+}
+template <class B, expression_template_option ET, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
+operator/(number<B, ET>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::divides, number<B, ET>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
 inline BOOST_MP_CXX14_CONSTEXPR detail::expression<detail::divides, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, ET> >
@@ -1054,17 +1121,22 @@ operator/(const number<B, ET>& a, const detail::expression<detail::negate, Arg1,
        detail::expression<detail::divides, number<B, ET>, Arg1>(a, b.left_ref()));
 }
 template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
-inline typename detail::expression<detail::negate, detail::expression<detail::divides, number<B, ET>, Arg1> >::result_type
+inline typename std::enable_if<
+   std::is_same<typename detail::expression<detail::negate, detail::expression<detail::divides, number<B, ET>, Arg1> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::divides, number<B, ET>, Arg1> >::result_type>::type
 operator/(number<B, ET>&& a, const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::negate, detail::expression<detail::divides, number<B, ET>, Arg1> >::result_type, number<B, ET>>::value)
-   {
-      a /= b.left_ref();
-      a.backend().negate();
-      return static_cast<number<B, ET>&&>(a);
-   }
-   else
-      return detail::expression<detail::negate, detail::expression<detail::divides, number<B, ET>, Arg1> >(
+   a /= b.left_ref();
+   a.backend().negate();
+   return static_cast<number<B, ET>&&>(a);
+}
+template <class B, expression_template_option ET, class Arg1, class Arg2, class Arg3, class Arg4>
+inline typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::negate, detail::expression<detail::divides, number<B, ET>, Arg1> >::result_type, number<B, ET>>::value,
+   typename detail::expression<detail::negate, detail::expression<detail::divides, number<B, ET>, Arg1> >::result_type>::type
+operator/(number<B, ET>&& a, const detail::expression<detail::negate, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::negate, detail::expression<detail::divides, number<B, ET>, Arg1> >(
          detail::expression<detail::divides, number<B, ET>, Arg1>(a, b.left_ref()));
 }
 template <class Arg1, class Arg2, class Arg3, class Arg4, class B, expression_template_option ET>
@@ -1225,17 +1297,23 @@ operator%(const number<B, et_on>& a, const detail::expression<tag, Arg1, Arg2, A
    return detail::expression<detail::modulus, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class B, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::modulus, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value 
+   && number_category<B>::value == number_kind_integer,
    typename detail::expression<detail::modulus, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type >::type
 operator%(number<B, et_on>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::modulus, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value)
-   {
-      a %= b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-      return detail::expression<detail::modulus, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
+   a %= b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::modulus, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value 
+   && number_category<B>::value == number_kind_integer,
+   typename detail::expression<detail::modulus, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type >::type
+operator%(number<B, et_on>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::modulus, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
 inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
@@ -1399,17 +1477,23 @@ operator&(const number<B, et_on>& a, const detail::expression<tag, Arg1, Arg2, A
    return detail::expression<detail::bitwise_and, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class B, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::bitwise_and, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
    typename detail::expression<detail::bitwise_and, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type >::type
 operator&(number<B, et_on>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::bitwise_and, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value)
-   {
-      a &= b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-      return detail::expression<detail::bitwise_and, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
+   a &= b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::bitwise_and, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
+   typename detail::expression<detail::bitwise_and, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type >::type
+operator&(number<B, et_on>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::bitwise_and, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
 inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
@@ -1419,17 +1503,23 @@ operator&(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, const number
    return detail::expression<detail::bitwise_and, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
-inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::bitwise_and, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
    typename detail::expression<detail::bitwise_and, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type >::type
 operator&(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, et_on>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::bitwise_and, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value)
-   {
-      b &= a;
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-      return detail::expression<detail::bitwise_and, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
+   b &= a;
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::bitwise_and, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
+   typename detail::expression<detail::bitwise_and, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type >::type
+operator&(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, et_on>&& b)
+{
+   return detail::expression<detail::bitwise_and, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class tag2, class Arg1b, class Arg2b, class Arg3b, class Arg4b>
 inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<typename detail::expression<tag, Arg1, Arg2, Arg3, Arg4>::result_type>::value == number_kind_integer,
@@ -1529,17 +1619,23 @@ operator|(const number<B, et_on>& a, const detail::expression<tag, Arg1, Arg2, A
    return detail::expression<detail::bitwise_or, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class B, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::bitwise_or, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
    typename detail::expression<detail::bitwise_or, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
 operator|(number<B, et_on>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::bitwise_or, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value)
-   {
-      a |= b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-      return detail::expression<detail::bitwise_or, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
+   a |= b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::bitwise_or, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
+   typename detail::expression<detail::bitwise_or, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
+operator|(number<B, et_on>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::bitwise_or, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
 inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
@@ -1549,17 +1645,23 @@ operator|(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, const number
    return detail::expression<detail::bitwise_or, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
-inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::bitwise_or, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
    typename detail::expression<detail::bitwise_or, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type>::type
 operator|(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, et_on>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::bitwise_or, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value)
-   {
-      b |= a;
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-      return detail::expression<detail::bitwise_or, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
+   b |= a;
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::bitwise_or, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
+   typename detail::expression<detail::bitwise_or, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type>::type
+operator|(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, et_on>&& b)
+{
+   return detail::expression<detail::bitwise_or, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class tag2, class Arg1b, class Arg2b, class Arg3b, class Arg4b>
 inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<typename detail::expression<tag, Arg1, Arg2, Arg3, Arg4>::result_type>::value == number_kind_integer,
@@ -1659,17 +1761,23 @@ operator^(const number<B, et_on>& a, const detail::expression<tag, Arg1, Arg2, A
    return detail::expression<detail::bitwise_xor, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class B, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
-inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::bitwise_xor, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
    typename detail::expression<detail::bitwise_xor, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
 operator^(number<B, et_on>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::bitwise_xor, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value)
-   {
-      a ^= b;
-      return static_cast<number<B, et_on>&&>(a);
-   }
-   else
-      return detail::expression<detail::bitwise_xor, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
+   a ^= b;
+   return static_cast<number<B, et_on>&&>(a);
+}
+template <class B, class tag, class Arg1, class Arg2, class Arg3, class Arg4>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::bitwise_xor, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
+   typename detail::expression<detail::bitwise_xor, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >::result_type>::type
+operator^(number<B, et_on>&& a, const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& b)
+{
+   return detail::expression<detail::bitwise_xor, number<B, et_on>, detail::expression<tag, Arg1, Arg2, Arg3, Arg4> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
 inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
@@ -1679,17 +1787,23 @@ operator^(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, const number
    return detail::expression<detail::bitwise_xor, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
-inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<B>::value == number_kind_integer,
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   std::is_same<typename detail::expression<detail::bitwise_xor, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
    typename detail::expression<detail::bitwise_xor, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type>::type
 operator^(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, et_on>&& b)
 {
-   BOOST_IF_CONSTEXPR(std::is_same<typename detail::expression<detail::bitwise_xor, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value)
-   {
-      b ^= a;
-      return static_cast<number<B, et_on>&&>(b);
-   }
-   else
-      return detail::expression<detail::bitwise_xor, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
+   b ^= a;
+   return static_cast<number<B, et_on>&&>(b);
+}
+template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class B>
+inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<
+   !std::is_same<typename detail::expression<detail::bitwise_xor, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type, number<B, et_on>>::value
+   && number_category<B>::value == number_kind_integer,
+   typename detail::expression<detail::bitwise_xor, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >::result_type>::type
+operator^(const detail::expression<tag, Arg1, Arg2, Arg3, Arg4>& a, number<B, et_on>&& b)
+{
+   return detail::expression<detail::bitwise_xor, detail::expression<tag, Arg1, Arg2, Arg3, Arg4>, number<B, et_on> >(a, b);
 }
 template <class tag, class Arg1, class Arg2, class Arg3, class Arg4, class tag2, class Arg1b, class Arg2b, class Arg3b, class Arg4b>
 inline BOOST_MP_CXX14_CONSTEXPR typename std::enable_if<number_category<typename detail::expression<tag, Arg1, Arg2, Arg3, Arg4>::result_type>::value == number_kind_integer,
diff --git a/include/boost/multiprecision/gmp.hpp b/include/boost/multiprecision/gmp.hpp
index 39c97a1f..603ed09b 100644
--- a/include/boost/multiprecision/gmp.hpp
+++ b/include/boost/multiprecision/gmp.hpp
@@ -2227,6 +2227,20 @@ struct gmp_rational
       mpz_init_set(&m_data[0]._mp_den, b.data());
       mpq_canonicalize(m_data);
    }
+   gmp_rational(const gmp_int& a, gmp_int&& b)
+   {
+      mpz_init_set(&m_data[0]._mp_num, a.data());
+      m_data[0]._mp_den = b.data()[0];
+      mpq_canonicalize(m_data);
+      b.data()[0]._mp_d = nullptr;
+   }
+   gmp_rational(gmp_int&& a, const gmp_int& b)
+   {
+      m_data[0]._mp_num = a.data()[0];
+      mpz_init_set(&m_data[0]._mp_den, b.data());
+      mpq_canonicalize(m_data);
+      a.data()[0]._mp_d = nullptr;
+   }
    gmp_rational(gmp_int&& a, gmp_int&& b)
    {
       m_data[0]._mp_num = a.data()[0];
@@ -2531,6 +2545,174 @@ inline void eval_divide(gmp_rational& t, const gmp_rational& p, const gmp_ration
       BOOST_THROW_EXCEPTION(std::overflow_error("Division by zero."));
    mpq_div(t.data(), p.data(), o.data());
 }
+//
+// operator with scalars:
+//
+inline void eval_add(gmp_rational& result, gmp_rational const& a, gmp_int const& b)
+{
+   // we allow result and a to be the same object here:
+   if (&a != &result)
+   {
+      mpz_set(mpq_numref(result.data()), mpq_numref(a.data()));
+      mpz_set(mpq_denref(result.data()), mpq_denref(a.data()));
+   }
+   mpz_addmul(mpq_numref(result.data()), mpq_denref(a.data()), b.data());
+   // no need to normalize, there can be no common divisor as long as a is already normalized.
+}
+inline void eval_add(gmp_rational& result, gmp_rational const& a, unsigned long b)
+{
+   // we allow result and a to be the same object here:
+   if (&a != &result)
+   {
+      mpz_set(mpq_numref(result.data()), mpq_numref(a.data()));
+      mpz_set(mpq_denref(result.data()), mpq_denref(a.data()));
+   }
+   mpz_addmul_ui(mpq_numref(result.data()), mpq_denref(a.data()), b);
+   // no need to normalize, there can be no common divisor as long as a is already normalized.
+}
+inline void eval_add(gmp_rational& result, gmp_rational const& a, long b)
+{
+   // we allow result and a to be the same object here:
+   if (&a != &result)
+   {
+      mpz_set(mpq_numref(result.data()), mpq_numref(a.data()));
+      mpz_set(mpq_denref(result.data()), mpq_denref(a.data()));
+   }
+   if(b > 0)
+      mpz_addmul_ui(mpq_numref(result.data()), mpq_denref(a.data()), b);
+   else
+      mpz_submul_ui(mpq_numref(result.data()), mpq_denref(a.data()), boost::multiprecision::detail::unsigned_abs(b));
+   // no need to normalize, there can be no common divisor as long as a is already normalized.
+}
+template <class T>
+inline void eval_add(gmp_rational& result, gmp_rational const& a, const T& b)
+{
+   gmp_int t;
+   t = b;
+   eval_add(result, a, t);
+}
+template <class T>
+inline void eval_add(gmp_rational& result, const T& b, gmp_rational const& a)
+{
+   eval_add(result, a, b);
+}
+template <class T>
+inline void eval_add(gmp_rational& result, const T& b)
+{
+   eval_add(result, result, b);
+}
+inline void eval_subtract(gmp_rational& result, gmp_rational const& a, gmp_int const& b)
+{
+   // we allow result and a to be the same object here:
+   if (&a != &result)
+   {
+      mpz_set(mpq_numref(result.data()), mpq_numref(a.data()));
+      mpz_set(mpq_denref(result.data()), mpq_denref(a.data()));
+   }
+   mpz_submul(mpq_numref(result.data()), mpq_denref(a.data()), b.data());
+   // no need to normalize, there can be no common divisor as long as a is already normalized.
+}
+inline void eval_subtract(gmp_rational& result, gmp_rational const& a, unsigned long b)
+{
+   // we allow result and a to be the same object here:
+   if (&a != &result)
+   {
+      mpz_set(mpq_numref(result.data()), mpq_numref(a.data()));
+      mpz_set(mpq_denref(result.data()), mpq_denref(a.data()));
+   }
+   mpz_submul_ui(mpq_numref(result.data()), mpq_denref(a.data()), b);
+   // no need to normalize, there can be no common divisor as long as a is already normalized.
+}
+inline void eval_subtract(gmp_rational& result, gmp_rational const& a, long b)
+{
+   // we allow result and a to be the same object here:
+   if (&a != &result)
+   {
+      mpz_set(mpq_numref(result.data()), mpq_numref(a.data()));
+      mpz_set(mpq_denref(result.data()), mpq_denref(a.data()));
+   }
+   if(b > 0)
+      mpz_submul_ui(mpq_numref(result.data()), mpq_denref(a.data()), b);
+   else
+      mpz_addmul_ui(mpq_numref(result.data()), mpq_denref(a.data()), boost::multiprecision::detail::unsigned_abs(b));
+   // no need to normalize, there can be no common divisor as long as a is already normalized.
+}
+template <class T>
+inline void eval_subtract(gmp_rational& result, gmp_rational const& a, const T& b)
+{
+   gmp_int t;
+   t = b;
+   eval_subtract(result, a, t);
+}
+template <class T>
+inline void eval_subtract(gmp_rational& result, const T& b, gmp_rational const& a)
+{
+   eval_subtract(result, a, b);
+   result.negate();
+}
+template <class T>
+inline void eval_subtract(gmp_rational& result, const T& b)
+{
+   eval_subtract(result, result, b);
+}
+
+inline void eval_multiply(gmp_rational& result, gmp_rational const& a, gmp_int const& b)
+{
+   gmp_int g, t;
+   mpz_gcd(g.data(), mpq_denref(a.data()), b.data());
+   if (!mpz_fits_uint_p(g.data()) || (mpz_get_ui(g.data()) != 1))
+   {
+      eval_divide(t, b, g);
+      mpz_mul(mpq_numref(result.data()), t.data(), mpq_numref(a.data()));
+      mpz_div(mpq_denref(result.data()), mpq_denref(a.data()), g.data());
+   }
+   else
+   {
+      mpz_mul(mpq_numref(result.data()), mpq_numref(a.data()), b.data());
+      if (&result != &a)
+         mpz_set(mpq_denref(result.data()), mpq_denref(a.data()));
+   }
+}
+inline void eval_multiply(gmp_rational& result, gmp_rational const& a, unsigned long b)
+{
+   gmp_int g;
+   mpz_gcd_ui(g.data(), mpq_denref(a.data()), b);
+   if (!mpz_fits_uint_p(g.data()) || (mpz_get_ui(g.data()) != 1))
+   {
+      b /= mpz_get_ui(g.data());
+      mpz_mul_ui(mpq_numref(result.data()), mpq_numref(a.data()), b);
+      mpz_div(mpq_denref(result.data()), mpq_denref(a.data()), g.data());
+   }
+   else
+   {
+      mpz_mul_ui(mpq_numref(result.data()), mpq_numref(a.data()), b);
+      if (&result != &a)
+         mpz_set(mpq_denref(result.data()), mpq_denref(a.data()));
+   }
+}
+inline void eval_multiply(gmp_rational& result, gmp_rational const& a, long b)
+{
+   eval_multiply(result, a, boost::multiprecision::detail::unsigned_abs(b));
+   if (b < 0)
+      result.negate();
+}
+template <class T>
+inline void eval_multiply(gmp_rational& result, gmp_rational const& a, const T& b)
+{
+   gmp_int t;
+   t = b;
+   eval_multiply(result, a, t);
+}
+template <class T>
+inline void eval_multiply(gmp_rational& result, const T& b, gmp_rational const& a)
+{
+   eval_multiply(result, a, b);
+}
+template <class T>
+inline void eval_multiply(gmp_rational& result, const T& b)
+{
+   eval_multiply(result, result, b);
+}
 
 inline int eval_get_sign(const gmp_rational& val)
 {
diff --git a/include/boost/multiprecision/logged_adaptor.hpp b/include/boost/multiprecision/logged_adaptor.hpp
index 628f6a19..6d7eb4e4 100644
--- a/include/boost/multiprecision/logged_adaptor.hpp
+++ b/include/boost/multiprecision/logged_adaptor.hpp
@@ -100,13 +100,15 @@ struct logged_adaptor
    {
       log_postfix_event(m_value, "construct from a pair of arithmetic types");
    }
-   logged_adaptor(const Backend& i, unsigned digits10)
+   template <class D = Backend>
+   logged_adaptor(const Backend& i, unsigned digits10, typename std::enable_if<std::is_constructible<D, Backend const&, unsigned>::value>::type const* = nullptr)
       : m_value(i, digits10)
    {
       log_postfix_event(m_value, "construct from arithmetic type and precision");
    }
-   logged_adaptor(const logged_adaptor<Backend>& i, unsigned digits10)
-      : m_value(i, digits10)
+   template <class D = Backend>
+   logged_adaptor(const logged_adaptor<Backend>& i, unsigned digits10, typename std::enable_if<std::is_constructible<D, Backend const&, unsigned>::value>::type const* = nullptr)
+      : m_value(i.value(), digits10)
    {
       log_postfix_event(m_value, "construct from arithmetic type and precision");
    }
diff --git a/include/boost/multiprecision/number.hpp b/include/boost/multiprecision/number.hpp
index 38cf288e..c6a238bb 100644
--- a/include/boost/multiprecision/number.hpp
+++ b/include/boost/multiprecision/number.hpp
@@ -158,7 +158,7 @@ class number
          (std::is_convertible<V, value_type>::value
             && std::is_convertible<U, value_type>::value
             && !std::is_same<value_type, self_type>::value
-            && std::is_constructible<Backend, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type const&, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type const&>::value
+            && std::is_constructible<Backend, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type>::type, Backend>::type const&, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type>::type, Backend>::type const&>::value
             && !boost::multiprecision::detail::is_variable_precision<Backend>::value)>::type* = 0)
       : m_backend(canonical_value(detail::evaluate_if_expression(v1)), canonical_value(detail::evaluate_if_expression(v2)))
    {
@@ -169,7 +169,7 @@ class number
          (std::is_convertible<V, value_type>::value
             && std::is_convertible<U, value_type>::value
             && !std::is_same<value_type, self_type>::value
-            && std::is_constructible<Backend, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type const&, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type const&>::value
+            && std::is_constructible<Backend, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type>::type, Backend>::type const&, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type>::type, Backend>::type const&>::value
             && !boost::multiprecision::detail::is_variable_precision<Backend>::value)>::type* = 0)
       : m_backend(canonical_value(detail::evaluate_if_expression(static_cast<V&&>(v1))), canonical_value(detail::evaluate_if_expression(v2)))
    {
@@ -180,7 +180,7 @@ class number
       (std::is_convertible<V, value_type>::value
          && std::is_convertible<U, value_type>::value
          && !std::is_same<value_type, self_type>::value
-         && std::is_constructible<Backend, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type const&, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type const&>::value
+         && std::is_constructible<Backend, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type>::type, Backend>::type const&, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type>::type, Backend>::type const&>::value
          && !boost::multiprecision::detail::is_variable_precision<Backend>::value)>::type* = 0)
       : m_backend(canonical_value(detail::evaluate_if_expression(v1)), canonical_value(detail::evaluate_if_expression(static_cast<U&&>(v2))))
    {
@@ -191,7 +191,7 @@ class number
       (std::is_convertible<V, value_type>::value
          && std::is_convertible<U, value_type>::value
          && !std::is_same<value_type, self_type>::value
-         && std::is_constructible<Backend, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type const&, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type const&>::value
+         && std::is_constructible<Backend, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type>::type, Backend>::type const&, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type>::type, Backend>::type const&>::value
          && !boost::multiprecision::detail::is_variable_precision<Backend>::value)>::type* = 0)
       : m_backend(canonical_value(detail::evaluate_if_expression(static_cast<V&&>(v1))), canonical_value(detail::evaluate_if_expression(static_cast<U&&>(v2))))
    {
@@ -202,7 +202,7 @@ class number
          (std::is_convertible<V, value_type>::value 
             && std::is_convertible<U, value_type>::value 
             && !std::is_same<value_type, self_type>::value
-            && (!std::is_constructible<Backend, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type const&, typename detail::canonical<Backend, decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type const&>::value
+            && (!std::is_constructible<Backend, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const V&>()))>::type>::type, Backend>::type const&, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const U&>()))>::type>::type, Backend>::type const&>::value
                || boost::multiprecision::detail::is_variable_precision<Backend>::value))>::type* = 0)
    {
       using default_ops::assign_components;
@@ -265,7 +265,12 @@ class number
        : m_backend(detail::evaluate_if_expression(v1), detail::evaluate_if_expression(v2), digits10) {}
 
    template <class Other, expression_template_option ET>
-   BOOST_MP_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR number(const number<Other, ET>& v1, const number<Other, ET>& v2, typename std::enable_if<std::is_convertible<Other, Backend>::value>::type* = 0)
+   BOOST_MP_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR number(
+      const number<Other, ET>& v1, 
+      const number<Other, ET>& v2, 
+      typename std::enable_if<
+         std::is_convertible<Other, Backend>::value 
+         && (!std::is_constructible<Backend, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const number<Other, ET>&>()))>::type>::type, Backend>::type const&, typename detail::canonical<typename remove_cv<typename remove_reference<decltype(detail::evaluate_if_expression(std::declval<const number<Other, ET>&>()))>::type>::type, Backend>::type const&>::value || boost::multiprecision::detail::is_variable_precision<Backend>::value) >::type* = 0)
    {
       using default_ops::assign_components;
       detail::scoped_default_precision<number<Backend, ExpressionTemplates> > precision_guard(v1, v2);
diff --git a/include/boost/multiprecision/rational_adaptor.hpp b/include/boost/multiprecision/rational_adaptor.hpp
index 530f9d85..b83bdce0 100644
--- a/include/boost/multiprecision/rational_adaptor.hpp
+++ b/include/boost/multiprecision/rational_adaptor.hpp
@@ -54,6 +54,23 @@ struct rational_adaptor
       return result;
    }
 
+   void normalize()
+   {
+      using default_ops::eval_gcd;
+      using default_ops::eval_eq;
+      using default_ops::eval_divide;
+
+      Backend g, t;
+      eval_gcd(g, m_num, m_denom);
+      if (!eval_eq(g, one()))
+      {
+         eval_divide(t, m_num, g);
+         m_num.swap(t);
+         eval_divide(t, m_denom, g);
+         m_denom = std::move(t);
+      }
+   }
+
    // We must have a default constructor:
    rational_adaptor()
       : m_num(one()), m_denom(one()) {}
@@ -70,6 +87,33 @@ struct rational_adaptor
    rational_adaptor(const Arithmetic& val, typename std::enable_if<std::is_constructible<Backend, Arithmetic>::value && !std::is_floating_point<Arithmetic>::value>::type const* = nullptr)
       : m_num(val), m_denom(one()) {}
 
+   //
+   // Pass-through 2-arg construction of components:
+   //
+   template <class T, class U>
+   rational_adaptor(const T& a, const U& b, typename std::enable_if<std::is_constructible<Backend, T const&>::value && std::is_constructible<Backend, U const&>::value>::type const* = nullptr)
+      : m_num(a), m_denom(b) 
+   {
+      normalize();
+   }
+   template <class T, class U>
+   rational_adaptor(T&& a, const U& b, typename std::enable_if<std::is_constructible<Backend, T>::value && std::is_constructible<Backend, U>::value>::type const* = nullptr)
+      : m_num(static_cast<T&&>(a)), m_denom(b) 
+   {
+      normalize();
+   }
+   template <class T, class U>
+   rational_adaptor(T&& a, U&& b, typename std::enable_if<std::is_constructible<Backend, T>::value && std::is_constructible<Backend, U>::value>::type const* = nullptr)
+      : m_num(static_cast<T&&>(a)), m_denom(static_cast<U&&>(b)) 
+   {
+      normalize();
+   }
+   template <class T, class U>
+   rational_adaptor(const T& a, U&& b, typename std::enable_if<std::is_constructible<Backend, T>::value && std::is_constructible<Backend, U>::value>::type const* = nullptr)
+      : m_num(a), m_denom(static_cast<U&&>(b)) 
+   {
+      normalize();
+   }
    //
    // In the absense of converting constructors, operator= takes the strain.
    // In addition to the usual suspects, there must be one operator= for each type
@@ -290,26 +334,20 @@ is_minus_one(const T& val)
 // Required non-members:
 //
 template <class Backend> 
-void eval_add(rational_adaptor<Backend>& a, const rational_adaptor<Backend>& b)
+inline void eval_add(rational_adaptor<Backend>& a, const rational_adaptor<Backend>& b)
 {
-   rational_adaptor<Backend> t;
-   eval_add(t, a, b);
-   a = std::move(t);
+   eval_add_subtract_imp(a, a, b, true);
 }
 template <class Backend> 
-void eval_subtract(rational_adaptor<Backend>& a, const rational_adaptor<Backend>& b)
+inline void eval_subtract(rational_adaptor<Backend>& a, const rational_adaptor<Backend>& b)
 {
-   rational_adaptor<Backend> t;
-   eval_subtract(t, a, b);
-   a = std::move(t);
+   eval_add_subtract_imp(a, a, b, false);
 }
 
 template <class Backend> 
-void eval_multiply(rational_adaptor<Backend>& a, const rational_adaptor<Backend>& b)
+inline void eval_multiply(rational_adaptor<Backend>& a, const rational_adaptor<Backend>& b)
 {
-   rational_adaptor<Backend> t;
-   eval_multiply(t, a, b);
-   a = std::move(t);
+   eval_multiply_imp(a, a, b.num(), b.denom());
 }
 
 template <class Backend> 
diff --git a/performance/rational_bernoulli_allocations.cpp b/performance/rational_bernoulli_allocations.cpp
new file mode 100644
index 00000000..f17e9bee
--- /dev/null
+++ b/performance/rational_bernoulli_allocations.cpp
@@ -0,0 +1,139 @@
+//  Copyright 2020 John Maddock. Distributed under the Boost
+//  Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
+
+#include <iostream>
+#include <benchmark/benchmark.h>
+#include <boost/multiprecision/cpp_int.hpp>
+#include <boost/multiprecision/gmp.hpp>
+
+#include <gmpxx.h>
+
+template <class Integer>
+inline Integer factorial(unsigned n)
+{
+   Integer result = 1;
+   for (unsigned k = 1; k <= n; ++k)
+      result *= k;
+   return result;
+}
+
+template <class Rational, class Integer = typename Rational::value_type>
+inline Rational binomial(unsigned n, unsigned k)
+{
+   return Rational(factorial<Integer>(n), factorial<Integer>(k) * factorial<Integer>(n - k));
+}
+
+inline mpz_class pow(mpz_class i, unsigned p)
+{
+   mpz_class result;
+   mpz_pow_ui(result.get_mpz_t(), i.get_mpz_t(), p);
+   return result;
+}
+
+template <class Rational, class Integer = typename Rational::value_type>
+Rational Bernoulli(unsigned m)
+{
+   Rational result = 0;
+
+   for (unsigned k = 0; k <= m; ++k)
+   {
+      Rational inner = 0;
+      for (unsigned v = 0; v <= k; ++v)
+      {
+         Rational term = binomial<Rational, Integer>(k, v) * Rational(pow(Integer(v), m), k + 1);
+         if (v & 1)
+            term = -term;
+         inner += term;
+      }
+      result += inner;
+   }
+   return result;
+}
+
+template <class Rational, class Integer = typename Rational::value_type>
+static void BM_bernoulli(benchmark::State& state)
+{
+   int m = state.range(0);
+   for (auto _ : state)
+   {
+      benchmark::DoNotOptimize(Bernoulli<Rational, Integer>(m));
+   }
+}
+
+unsigned allocation_count = 0;
+
+void* (*alloc_func_ptr)(size_t);
+void* (*realloc_func_ptr)(void*, size_t, size_t);
+void (*free_func_ptr)(void*, size_t);
+
+void* alloc_func(size_t n)
+{
+   ++allocation_count;
+   return (*alloc_func_ptr)(n);
+}
+
+void free_func(void* p, size_t n)
+{
+   (*free_func_ptr)(p, n);
+}
+
+void* realloc_func(void* p, size_t old, size_t n)
+{
+   ++allocation_count;
+   return (*realloc_func_ptr)(p, old, n);
+}
+
+unsigned new_count = 0;
+
+void* operator new(std::size_t n) throw(std::bad_alloc)
+{
+   ++new_count;
+   return std::malloc(n);
+}
+void operator delete(void* p) throw()
+{
+   std::free(p);
+}
+
+void* operator new[](std::size_t n) throw(std::bad_alloc)
+{
+   ++new_count;
+   return std::malloc(n);
+}
+void operator delete[](void* p) throw()
+{
+   std::free(p);
+}
+
+
+int main()
+{
+   using namespace boost::multiprecision;
+
+   mp_get_memory_functions(&alloc_func_ptr, &realloc_func_ptr, &free_func_ptr);
+   mp_set_memory_functions(&alloc_func, &realloc_func, &free_func);
+
+   std::cout << "[table Total Allocation Counts for Bernoulli Number Calculation\n"
+      "[[m][cpp_rational][mpq_rational][number<rational_adaptor<gmp_int>>][mpq_class]]\n";
+
+   for (unsigned m = 2; m < 200; m += 2)
+   {
+      std::cout << "[[" << m << "][";
+      new_count = 0;
+      Bernoulli<cpp_rational>(m);
+      std::cout << new_count << "][";
+      allocation_count = 0;
+      Bernoulli<mpq_rational>(m);
+      std::cout << allocation_count << "][";
+      allocation_count = 0;
+      Bernoulli<number<rational_adaptor<gmp_int>>>(m);
+      std::cout << allocation_count << "][";
+      allocation_count = 0;
+      Bernoulli<mpq_class, mpz_class>(m);
+      std::cout << allocation_count << "]]\n";
+   }
+
+   std::cout << "]\n";
+   return 0;
+}
diff --git a/performance/rational_bernoulli_bench.cpp b/performance/rational_bernoulli_bench.cpp
index a96bf8c9..d00618e8 100644
--- a/performance/rational_bernoulli_bench.cpp
+++ b/performance/rational_bernoulli_bench.cpp
@@ -62,9 +62,9 @@ static void BM_bernoulli(benchmark::State& state)
 }
 
 
-BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::cpp_rational)->DenseRange(10, 100, 2);
-BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::mpq_rational)->DenseRange(10, 100, 2);
-BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::number<boost::multiprecision::rational_adaptor<boost::multiprecision::gmp_int>>)->DenseRange(10, 100, 2);
-BENCHMARK_TEMPLATE(BM_bernoulli, mpq_class, mpz_class)->DenseRange(10, 100, 2);
+BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::cpp_rational)->DenseRange(50, 200, 4);
+BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::mpq_rational)->DenseRange(50, 200, 4);
+BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::number<boost::multiprecision::rational_adaptor<boost::multiprecision::gmp_int> >)->DenseRange(50, 200, 4);
+BENCHMARK_TEMPLATE(BM_bernoulli, mpq_class, mpz_class)->DenseRange(50, 200, 4);
 
 BENCHMARK_MAIN();