Implement literal suffixes for compled

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192048 91177308-0d34-0410-b5e6-96231b3b80d8

include/complex

@@ -1521,6 +1521,47 @@ operator<<(basic_ostream<_CharT, _Traits>& __os, const complex<_Tp>& __x)
     return __os << __s.str();
 }
 
+#if _LIBCPP_STD_VER > 11 
+// Literal suffix for complex number literals [complex.literals]
+inline namespace literals
+{ 
+  inline namespace complex_literals
+  {
+    constexpr complex<long double> operator""il(long double __im)
+    {
+        return { 0.0l, __im };
+    }
+
+    constexpr complex<long double> operator""il(unsigned long long __im)
+    {
+        return { 0.0l, static_cast<long double>(__im) };
+    }
+
+
+    constexpr complex<double> operator""i(long double __im)
+    {
+        return { 0.0, static_cast<double>(__im) };
+    }
+
+    constexpr complex<double> operator""i(unsigned long long __im)
+    {
+        return { 0.0, static_cast<double>(__im) };
+    }
+
+
+    constexpr complex<float> operator""if(long double __im)
+    {
+        return { 0.0f, static_cast<float>(__im) };
+    }
+
+    constexpr complex<float> operator""if(unsigned long long __im)
+    {
+        return { 0.0f, static_cast<float>(__im) };
+    }
+  }
+}
+#endif
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP_COMPLEX