Try alternate addition algo-implementation

Author: ckormanyos

include/boost/multiprecision/cpp_df_qf/cpp_df_qf_detail.hpp

@@ -87,13 +87,7 @@ struct exact_arithmetic
       return result;
    }
 
-   static
-   #if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-   BOOST_MP_CXX14_CONSTEXPR
-   #else
-   constexpr
-   #endif
-   void sum(float_pair& result, float_type a, float_type b)
+   static constexpr void sum(float_pair& result, float_type a, float_type b)
    {
       // Exact addition of two floating point numbers
       const float_type a_plus_b = a + b;
@@ -105,13 +99,7 @@ struct exact_arithmetic
       result.second = tmp.second;
    }
 
-   static
-   #if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-   BOOST_MP_CXX14_CONSTEXPR
-   #else
-   constexpr
-   #endif
-   void normalize(float_pair& result, float_type a, float_type b)
+   static constexpr void normalize(float_pair& result, float_type a, float_type b)
    {
       // Converts a pair of floats to standard form.
       const float_pair tmp = fast_sum(a, b);
@@ -120,13 +108,7 @@ struct exact_arithmetic
       result.second = tmp.second;
    }
 
-   static
-   #if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-   BOOST_MP_CXX14_CONSTEXPR
-   #else
-   constexpr
-   #endif
-   float_pair split(const float_type& a)
+   static constexpr float_pair split(const float_type& a)
    {
       // Split a floating point number in two (high and low) parts approximating the
       // upper-half and lower-half bits of the float
@@ -177,13 +159,7 @@ struct exact_arithmetic
       return std::make_pair(hi, lo);
    }
 
-   static
-   #if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-   BOOST_MP_CXX14_CONSTEXPR
-   #else
-   constexpr
-   #endif
-   float_pair product(const float_type& a, const float_type& b)
+   static constexpr float_pair product(const float_type& a, const float_type& b)
    {
       // Exact product of two floating point numbers
       const float_pair a_split = split(a);

include/boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_frexp.hpp

@@ -21,12 +21,7 @@ namespace detail
 {
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real frexp_zero_impl(Real arg, int* exp)
+constexpr Real frexp_zero_impl(Real arg, int* exp)
 {
    if (exp != nullptr)
    {
@@ -37,12 +32,7 @@ Real frexp_zero_impl(Real arg, int* exp)
 }
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real frexp_impl(Real arg, int* expptr)
+constexpr Real frexp_impl(Real arg, int* expptr)
 {
    Real f = arg;
 
@@ -79,12 +69,7 @@ Real frexp_impl(Real arg, int* expptr)
 }
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real frexp_impl_lt_half(Real arg, int* expptr)
+constexpr Real frexp_impl_lt_half(Real arg, int* expptr)
 {
    Real f = arg;
 
@@ -123,12 +108,7 @@ Real frexp_impl_lt_half(Real arg, int* expptr)
 } // namespace detail
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real frexp(Real arg, int* expptr)
+constexpr Real frexp(Real arg, int* expptr)
 {
    if (   (arg == Real(0))
        || (arg == Real(-0))

include/boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_ldexp.hpp

@@ -18,12 +18,7 @@ namespace boost { namespace multiprecision { namespace backends { namespace cpp_
 namespace detail {
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real ldexp_impl(Real arg, int exp) noexcept
+constexpr Real ldexp_impl(Real arg, int exp) noexcept
 {
     while(exp > 0)
     {

include/boost/multiprecision/cpp_df_qf/cpp_df_qf_detail_ccmath_sqrt.hpp

@@ -17,47 +17,27 @@ namespace boost { namespace multiprecision { namespace backends { namespace cpp_
 namespace detail {
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real sqrt_impl_2(Real x, Real s, Real s2)
+constexpr Real sqrt_impl_2(Real x, Real s, Real s2)
 {
    return !(s < s2) ? s2 : sqrt_impl_2(x, (x / s + s) / 2, s);
 }
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real sqrt_impl_1(Real x, Real s)
+constexpr Real sqrt_impl_1(Real x, Real s)
 {
    return sqrt_impl_2(x, (x / s + s) / 2, s);
 }
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real sqrt_impl(Real x)
+constexpr Real sqrt_impl(Real x)
 {
    return sqrt_impl_1(x, x > 1 ? x : Real(1));
 }
 
 } // namespace detail
 
 template <typename Real>
-#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
-BOOST_MP_CXX14_CONSTEXPR
-#else
-constexpr
-#endif
-Real sqrt(Real x)
+constexpr Real sqrt(Real x)
 {
    return cpp_df_qf_detail::ccmath::isnan(x) ? ccmath::numeric_limits<Real>::quiet_NaN() :
           cpp_df_qf_detail::ccmath::isinf(x) ? ccmath::numeric_limits<Real>::infinity() :