4 files changed, 18 insertions, 10 deletions
diff --git a/libcxx/include/__cxx03/__atomic/atomic.h b/libcxx/include/__cxx03/__atomic/atomic.h
index bc4a393..f2e8493 100644
--- a/libcxx/include/__cxx03/__atomic/atomic.h
+++ b/libcxx/include/__cxx03/__atomic/atomic.h
@@ -34,9 +34,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
 struct atomic : public __atomic_base<_Tp> {
-  using __base          = __atomic_base<_Tp>;
-  using value_type      = _Tp;
-  using difference_type = value_type;
+  using __base = __atomic_base<_Tp>;
 
   _LIBCPP_HIDE_FROM_ABI atomic() _NOEXCEPT = default;
 
@@ -59,8 +57,8 @@ struct atomic : public __atomic_base<_Tp> {
 
 template <class _Tp>
 struct atomic<_Tp*> : public __atomic_base<_Tp*> {
-  using __base          = __atomic_base<_Tp*>;
-  using value_type      = _Tp*;
+  using __base = __atomic_base<_Tp*>;
+
   using difference_type = ptrdiff_t;
 
   _LIBCPP_HIDE_FROM_ABI atomic() _NOEXCEPT = default;
diff --git a/libcxx/include/__cxx03/__atomic/atomic_base.h b/libcxx/include/__cxx03/__atomic/atomic_base.h
index a2b40c6..d79ef7d 100644
--- a/libcxx/include/__cxx03/__atomic/atomic_base.h
+++ b/libcxx/include/__cxx03/__atomic/atomic_base.h
@@ -32,6 +32,8 @@ struct __atomic_base // false
 {
   mutable __cxx_atomic_impl<_Tp> __a_;
 
+  using value_type = _Tp;
+
   _LIBCPP_HIDE_FROM_ABI bool is_lock_free() const volatile _NOEXCEPT {
     return __cxx_atomic_is_lock_free(sizeof(__cxx_atomic_impl<_Tp>));
   }
@@ -127,6 +129,8 @@ template <class _Tp>
 struct __atomic_base<_Tp, true> : public __atomic_base<_Tp, false> {
   using __base = __atomic_base<_Tp, false>;
 
+  using difference_type = typename __base::value_type;
+
   _LIBCPP_HIDE_FROM_ABI __atomic_base() _NOEXCEPT = default;
 
   _LIBCPP_HIDE_FROM_ABI __atomic_base(_Tp __d) _NOEXCEPT : __base(__d) {}
diff --git a/libcxx/include/__cxx03/sstream b/libcxx/include/__cxx03/sstream
index 44c2423..741158a 100644
--- a/libcxx/include/__cxx03/sstream
+++ b/libcxx/include/__cxx03/sstream
@@ -354,9 +354,15 @@ private:
 
 public:
   // [stringbuf.cons] constructors:
-  _LIBCPP_HIDE_FROM_ABI basic_stringbuf() : __hm_(nullptr), __mode_(ios_base::in | ios_base::out) {}
+  _LIBCPP_HIDE_FROM_ABI basic_stringbuf() : __hm_(nullptr), __mode_(ios_base::in | ios_base::out) {
+    // it is implementation-defined whether we initialize eback() & friends to nullptr, and libc++ doesn't
+    __init_buf_ptrs();
+  }
 
-  _LIBCPP_HIDE_FROM_ABI explicit basic_stringbuf(ios_base::openmode __wch) : __hm_(nullptr), __mode_(__wch) {}
+  _LIBCPP_HIDE_FROM_ABI explicit basic_stringbuf(ios_base::openmode __wch) : __hm_(nullptr), __mode_(__wch) {
+    // it is implementation-defined whether we initialize eback() & friends to nullptr, and libc++ doesn't
+    __init_buf_ptrs();
+  }
 
   _LIBCPP_HIDE_FROM_ABI explicit basic_stringbuf(const string_type& __s,
                                                  ios_base::openmode __wch = ios_base::in | ios_base::out)
diff --git a/libcxx/include/__cxx03/vector b/libcxx/include/__cxx03/vector
index 4b62e0b..dbaa33c 100644
--- a/libcxx/include/__cxx03/vector
+++ b/libcxx/include/__cxx03/vector
@@ -432,10 +432,12 @@ public:
   template <__enable_if_t<__is_allocator<_Allocator>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI vector(size_type __n, const value_type& __x, const allocator_type& __a)
       : __end_cap_(nullptr, __a) {
+    auto __guard = std::__make_exception_guard(__destroy_vector(*this));
     if (__n > 0) {
       __vallocate(__n);
       __construct_at_end(__n, __x);
     }
+    __guard.__complete();
   }
 
   template <class _InputIterator,
@@ -1054,9 +1056,7 @@ inline _LIBCPP_HIDE_FROM_ABI vector<_Tp, _Allocator>::vector(vector&& __x, const
     __x.__begin_ = __x.__end_ = __x.__end_cap() = nullptr;
   } else {
     typedef move_iterator<iterator> _Ip;
-    auto __guard = std::__make_exception_guard(__destroy_vector(*this));
-    assign(_Ip(__x.begin()), _Ip(__x.end()));
-    __guard.__complete();
+    __init_with_size(_Ip(__x.begin()), _Ip(__x.end()), __x.size());
   }
 }