diff --git a/libcxx/include/string b/libcxx/include/string
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -4165,10 +4165,11 @@
           const basic_string<_CharT, _Traits, _Allocator>& __rhs)
 {
     using _String = basic_string<_CharT, _Traits, _Allocator>;
-    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
     typename _String::size_type __lhs_sz = __lhs.size();
     typename _String::size_type __rhs_sz = __rhs.size();
-    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
+    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
+    __r.reserve(__lhs_sz + __rhs_sz);
+    __r.append(__lhs.data(), __lhs_sz);
     __r.append(__rhs.data(), __rhs_sz);
     return __r;
 }
@@ -4178,10 +4179,11 @@
 operator+(const _CharT* __lhs , const basic_string<_CharT,_Traits,_Allocator>& __rhs)
 {
     using _String = basic_string<_CharT, _Traits, _Allocator>;
-    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__rhs.get_allocator()));
     typename _String::size_type __lhs_sz = _Traits::length(__lhs);
     typename _String::size_type __rhs_sz = __rhs.size();
-    __r.__init(__lhs, __lhs_sz, __lhs_sz + __rhs_sz);
+    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__rhs.get_allocator()));
+    __r.reserve(__lhs_sz + __rhs_sz);
+    __r.append(__lhs, __lhs_sz);
     __r.append(__rhs.data(), __rhs_sz);
     return __r;
 }
@@ -4191,9 +4193,10 @@
 operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Allocator>& __rhs)
 {
     using _String = basic_string<_CharT, _Traits, _Allocator>;
-    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__rhs.get_allocator()));
     typename _String::size_type __rhs_sz = __rhs.size();
-    __r.__init(&__lhs, 1, 1 + __rhs_sz);
+    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__rhs.get_allocator()));
+    __r.reserve(__rhs_sz + 1);
+    __r.push_back(__lhs);
     __r.append(__rhs.data(), __rhs_sz);
     return __r;
 }
@@ -4204,10 +4207,11 @@
 operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
 {
     using _String = basic_string<_CharT, _Traits, _Allocator>;
-    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
     typename _String::size_type __lhs_sz = __lhs.size();
     typename _String::size_type __rhs_sz = _Traits::length(__rhs);
-    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
+    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
+    __r.reserve(__lhs_sz + __rhs_sz);
+    __r.append(__lhs.data(), __lhs_sz);
     __r.append(__rhs, __rhs_sz);
     return __r;
 }
@@ -4217,9 +4221,10 @@
 operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, _CharT __rhs)
 {
     using _String = basic_string<_CharT, _Traits, _Allocator>;
-    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
     typename _String::size_type __lhs_sz = __lhs.size();
-    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + 1);
+    _String __r(_String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
+    __r.reserve(__lhs_sz + 1);
+    __r.append(__lhs.data(), __lhs_sz);
     __r.push_back(__rhs);
     return __r;
 }