diff --git a/include/boost/multiprecision/cpp_bin_float.hpp b/include/boost/multiprecision/cpp_bin_float.hpp
index 38f53875..3c6760ad 100644
--- a/include/boost/multiprecision/cpp_bin_float.hpp
+++ b/include/boost/multiprecision/cpp_bin_float.hpp
@@ -1237,26 +1237,25 @@ inline typename boost::enable_if_c<boost::is_float<Float>::value>::type eval_con
    //
    typedef cpp_bin_float<std::numeric_limits<Float>::digits, digit_base_2, void, Exponent, MinE, MaxE>  conv_type;
    typedef typename common_type<typename conv_type::exponent_type, int>::type                           common_exp_type;
-   conv_type arg(original_arg);
-   switch(arg.exponent())
+   switch(original_arg.exponent())
    {
-   case conv_type::exponent_zero:
+   case cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE>::exponent_zero:
       *res = 0;
-      if(arg.sign())
+      if(original_arg.sign())
          *res = -*res;
       return;
-   case conv_type::exponent_nan:
+   case cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE>::exponent_nan:
       *res = std::numeric_limits<Float>::quiet_NaN();
       return;
-   case conv_type::exponent_infinity:
+   case cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE>::exponent_infinity:
       *res = (std::numeric_limits<Float>::infinity)();
-      if(arg.sign())
+      if(original_arg.sign())
          *res = -*res;
       return;
    }
-   common_exp_type e = arg.exponent();
    static const common_exp_type min_exp_limit = std::numeric_limits<Float>::min_exponent 
       - (common_exp_type)cpp_bin_float<std::numeric_limits<Float>::digits, digit_base_2, void, Exponent, MinE, MaxE>::bit_count - std::numeric_limits<Float>::digits - 2;
+   common_exp_type e = original_arg.exponent();
    e -= cpp_bin_float<std::numeric_limits<Float>::digits, digit_base_2, void, Exponent, MinE, MaxE>::bit_count - 1;
    if(e < min_exp_limit)
    {
@@ -1268,7 +1267,22 @@ inline typename boost::enable_if_c<boost::is_float<Float>::value>::type eval_con
       *res = std::numeric_limits<Float>::has_infinity ? std::numeric_limits<Float>::infinity() : (std::numeric_limits<Float>::max)();
       return;
    }
+   if(original_arg.exponent() < std::numeric_limits<Float>::min_exponent - 1)
+   {
+      // Result is not zero but is denormalized, in order to avoid double rounding we need to use
+      // a little trickery to ensure rounding occurs in the right place, and just once, thanks
+      // to Michael Shatz for this, see: https://svn.boost.org/trac/boost/attachment/ticket/12527
+      using default_ops::eval_add;
+      cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE> temp(original_arg);
+      eval_add(temp, original_arg.sign() ? -std::numeric_limits<Float>::min() : std::numeric_limits<Float>::min());
+      eval_convert_to(res, temp);
+      *res -= original_arg.sign() ? -std::numeric_limits<Float>::min() : std::numeric_limits<Float>::min();
+      return;
+   }
 
+   conv_type arg(original_arg);
+   e = arg.exponent();
+   e -= cpp_bin_float<std::numeric_limits<Float>::digits, digit_base_2, void, Exponent, MinE, MaxE>::bit_count - 1;
    *res = std::ldexp(static_cast<Float>(*arg.bits().limbs()), static_cast<int>(e));
    for(unsigned i = 1; i < arg.bits().size(); ++i)
    {
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index ce2637e1..92be0b98 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -493,7 +493,9 @@ run test_convert_from_float128.cpp
 #
 # This take too long to run as a regular part of the tests:
 #
-# run test_cpp_bin_float_round.cpp mpfr gmp ;
+run test_cpp_bin_float_round.cpp mpfr gmp ;
+explicit test_cpp_bin_float_round ;
+
 run test_cpp_bin_float_conv.cpp ;
 
 run test_cpp_bin_float_io.cpp no_eh_support /boost/system//boost_system /boost/chrono//boost_chrono
diff --git a/test/test_cpp_bin_float_conv.cpp b/test/test_cpp_bin_float_conv.cpp
index e49bf907..ad075841 100644
--- a/test/test_cpp_bin_float_conv.cpp
+++ b/test/test_cpp_bin_float_conv.cpp
@@ -89,6 +89,37 @@ int main()
    boost::multiprecision::number<boost::multiprecision::backends::cpp_bin_float<128, boost::multiprecision::backends::digit_base_2, void, int64_t> > ext_float("1e-646456978");
    BOOST_CHECK_EQUAL(ext_float.convert_to<float>(), 0);
 
+   q = -(std::numeric_limits<float>::min)();
+   BOOST_CHECK_EQUAL(q.convert_to<float>(), -(std::numeric_limits<float>::min)());
+   q = -(std::numeric_limits<float>::max)();
+   BOOST_CHECK_EQUAL(q.convert_to<float>(), -(std::numeric_limits<float>::max)());
+   q = -(std::numeric_limits<float>::denorm_min)();
+   BOOST_CHECK_EQUAL(q.convert_to<float>(), -(std::numeric_limits<float>::denorm_min)());
+   // See https://svn.boost.org/trac/boost/ticket/12512:
+   ext_float = boost::multiprecision::number<boost::multiprecision::backends::cpp_bin_float<128, boost::multiprecision::backends::digit_base_2, void, int64_t> >("-1e-646456978");
+   BOOST_CHECK_EQUAL(ext_float.convert_to<float>(), 0);
+   //
+   // Check for double rounding when the result would be a denorm.
+   // See https://svn.boost.org/trac/boost/ticket/12527
+   //
+   cpp_bin_float_50 r1 = ldexp(cpp_bin_float_50(0x8000000000000bffull), -63 - 1023);
+   double d1 = r1.convert_to<double>();
+   double d2 = boost::math::nextafter(d1, d1 < r1 ? DBL_MAX : -DBL_MAX);
+   BOOST_CHECK(((abs(d1 - r1) <= abs(d2 - r1))));
+   r1 = -r1;
+   d1 = r1.convert_to<double>();
+   d2 = boost::math::nextafter(d1, d1 < r1 ? DBL_MAX : -DBL_MAX);
+   BOOST_CHECK(((abs(d1 - r1) <= abs(d2 - r1))));
+
+   r1 = ldexp(cpp_bin_float_50(0x8000017f), -31 - 127);
+   float f1 = r1.convert_to<float>();
+   float f2 = boost::math::nextafter(f1, f1 < r1 ? FLT_MAX : -FLT_MAX);
+   BOOST_CHECK(((abs(f1 - r1) <= abs(f2 - r1))));
+   r1 = -r1;
+   f1 = r1.convert_to<float>();
+   f2 = boost::math::nextafter(f1, f1 < r1 ? FLT_MAX : -FLT_MAX);
+   BOOST_CHECK(((abs(f1 - r1) <= abs(f2 - r1))));
+
    return boost::report_errors();
 }