diff --git a/libstdc++-v3/include/std/bitset b/libstdc++-v3/include/std/bitset
index 3243c649731..16c4040f532 100644
--- a/libstdc++-v3/include/std/bitset
+++ b/libstdc++-v3/include/std/bitset
@@ -177,8 +177,15 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       _GLIBCXX14_CONSTEXPR void
       _M_do_set() _GLIBCXX_NOEXCEPT
       {
-	for (size_t __i = 0; __i < _Nw; __i++)
-	  _M_w[__i] = ~static_cast<_WordT>(0);
+#if __cplusplus >= 201402L
+	if (__builtin_is_constant_evaluated())
+	  {
+	    for (_WordT& __w : _M_w)
+	      __w = ~static_cast<_WordT>(0);;
+	    return;
+	  }
+#endif
+	__builtin_memset(_M_w, 0xFF, _Nw * sizeof(_WordT));
       }
 
       _GLIBCXX14_CONSTEXPR void