Hashtable consider all initializer_list on insertion

diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index 07a4abe5c33..d530005f05f 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -529,9 +529,11 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		 const _Hash& __hf = _Hash(),
 		 const key_equal& __eql = key_equal(),
 		 const allocator_type& __a = allocator_type())
-      : _Hashtable(__l.begin(), __l.end(), __bkt_count_hint,
-		   __hf, __eql, __a, __unique_keys{})
-      { }
+      : _Hashtable(__bkt_count_hint, __hf, __eql, __a)
+      {
+	__alloc_node_gen_t __alloc_node_gen(*this);
+	this->_M_initialize(__l, __alloc_node_gen);
+      }
 
       _Hashtable&
       operator=(const _Hashtable& __ht);
@@ -556,14 +558,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	_M_before_begin._M_nxt = nullptr;
 	clear();
 
-	// We consider that all elements of __l are going to be inserted.
-	auto __l_bkt_count = _M_rehash_policy._M_bkt_for_elements(__l.size());
-
-	// Do not shrink to keep potential user reservation.
-	if (_M_bucket_count < __l_bkt_count)
-	  rehash(__l_bkt_count);
-
-	this->_M_insert_range(__l.begin(), __l.end(), __roan, __unique_keys{});
+	this->_M_initialize(__l, __roan);
 	return *this;
       }
 
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h
index 0109ef86a7b..6ad09db10a0 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -825,6 +825,25 @@  namespace __detail
 	_M_insert_range(_InputIterator __first, _InputIterator __last,
 			const _NodeGetter&, false_type __uks);
 
+      template<typename _NodeGetter>
+	void
+	_M_initialize(initializer_list<value_type> __l,
+		      const _NodeGetter& __node_gen)
+	{
+	  __hashtable& __h = _M_conjure_hashtable();
+
+	  // We consider that all elements of __l are going to be inserted.
+	  auto __l_bkt_count
+	    = __h._M_rehash_policy._M_bkt_for_elements(__l.size());
+
+	  // Do not shrink to keep potential user reservation.
+	  if (__h._M_bucket_count < __l_bkt_count)
+	    __h.rehash(__l_bkt_count);
+
+	  this->_M_insert_range(__l.begin(), __l.end(), __node_gen,
+				__unique_keys{});
+	}
+
     public:
       __ireturn_type
       insert(const value_type& __v)
@@ -866,7 +885,16 @@  namespace __detail
 
       void
       insert(initializer_list<value_type> __l)
-      { this->insert(__l.begin(), __l.end()); }
+      {
+	__hashtable& __h = _M_conjure_hashtable();
+	if (__h.empty())
+	  {
+	    __node_gen_type __node_gen(__h);
+	    _M_initialize(__l, __node_gen);
+	  }
+	else
+	  this->insert(__l.begin(), __l.end());
+      }
 
       template<typename _InputIterator>
 	void
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/cons/bucket_hint.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/cons/bucket_hint.cc
index 100eb5a27df..424e8f68c28 100644
--- a/libstdc++-v3/testsuite/23_containers/unordered_set/cons/bucket_hint.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/cons/bucket_hint.cc
@@ -23,15 +23,6 @@ 
 
 #include <testsuite_hooks.h>
 
-void test01()
-{
-  std::unordered_set<int> a;
-  a.reserve(2);
-
-  std::unordered_set<int> b({ 0, 1, 0, 1, 0, 1, 0, 1 }, a.bucket_count());
-  VERIFY( b.bucket_count() == a.bucket_count() );
-}
-
 void test02()
 {
   std::unordered_set<int> a;
@@ -56,7 +47,6 @@  void test03()
 
 int main()
 {
-  test01();
   test02();
   test03();
   return 0;
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/init-list.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/init-list.cc
index 66efa72f262..e86f90b1361 100644
--- a/libstdc++-v3/testsuite/23_containers/unordered_set/init-list.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/init-list.cc
@@ -48,8 +48,27 @@  void test01()
   VERIFY(m.count(1) == 0);
 }
 
+void test02()
+{
+  unordered_set<int> u({ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 });
+  VERIFY( u.size() == 13 );
+  VERIFY( u.count(0) == 1 );
+  VERIFY( u.count(13) == 0 );
+
+  auto bkt_count = u.bucket_count();
+  u.insert({ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 });
+  VERIFY( u.size() == 13 );
+  VERIFY( u.bucket_count() == bkt_count );
+
+  u.clear();
+  u.insert({ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 });
+  VERIFY( u.size() == 13 );
+  VERIFY( u.bucket_count() == bkt_count );
+}
+
 int main()
 {
   __gnu_test::set_memory_limits();
   test01();
+  test02();
 }
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/modifiers/insert.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/modifiers/insert.cc
index acf01c73b1b..7e4d3c06cb9 100644
--- a/libstdc++-v3/testsuite/23_containers/unordered_set/modifiers/insert.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/modifiers/insert.cc
@@ -23,16 +23,6 @@ 
 
 #include <testsuite_hooks.h>
 
-void test01()
-{
-  std::unordered_set<int> a;
-  a.reserve(2);
-
-  auto bkt_count = a.bucket_count();
-  a.insert({ 0, 1, 0, 1, 0, 1, 0, 1 });
-  VERIFY( a.bucket_count() == bkt_count );
-}
-
 void test02()
 {
   std::unordered_set<int> a;
@@ -59,7 +49,6 @@  void test03()
 
 int main()
 {
-  test01();
   test02();
   test03();
   return 0;