Optimize comparison operators

Author: greg7mdp

include/intx/intx.hpp

@@ -1211,24 +1211,15 @@ inline constexpr bool operator!=(const T& x, const uint<N>& y) noexcept
     return uint<N>(x) != y;
 }
 
-#if !defined(_MSC_VER) || _MSC_VER < 1916  // This kills MSVC 2017 compiler.
-inline constexpr bool operator<(const uint256& x, const uint256& y) noexcept
-{
-    auto xp = uint128{x[2], x[3]};
-    auto yp = uint128{y[2], y[3]};
-    if (xp == yp)
-    {
-        xp = uint128{x[0], x[1]};
-        yp = uint128{y[0], y[1]};
-    }
-    return xp < yp;
-}
-#endif
-
 template <unsigned N>
 inline constexpr bool operator<(const uint<N>& x, const uint<N>& y) noexcept
 {
-    return subc(x, y).carry;
+    for (auto i = uint<N>::num_words - 1; i > 0; --i)
+    {
+        if (x[i] != y[i])
+            return x[i] < y[i];
+    }
+    return x[0] < y[0];
 }
 
 template <unsigned N, typename T,