PR libstdc++/78595 implement insertion into maps in terms of emplace

C++14 simplified the specification of the generic insert function
templates to be equivalent to calling emplace (or emplace_hint).
Defining them in terms of emplace takes care of the problems described
in PR 78595, ensuring a single conversion to value_type is done at the
right time.

	PR libstdc++/78595
	* include/bits/stl_map.h (map::insert(_Pair&&))
	(map::insert(const_iterator, _Pair&&)): Do emplace instead of insert.
	* include/bits/stl_multimap.h (multimap::insert(_Pair&&))
	(multimap::insert(const_iterator, _Pair&&)): Likewise.
	* include/bits/unordered_map.h (unordered_map::insert(_Pair&&))
	(unordered_map::insert(const_iterator, _Pair&&))
	(unordered_multimap::insert(_Pair&&))
	(unordered_multimap::insert(const_iterator, _Pair&&)): Likewise.
	* testsuite/23_containers/map/modifiers/insert/78595.cc: New test.
	* testsuite/23_containers/multimap/modifiers/insert/78595.cc: New test.
	* testsuite/23_containers/unordered_map/modifiers/78595.cc: New test.
	* testsuite/23_containers/unordered_multimap/modifiers/78595.cc: New
	test.

From-SVN: r264059

libstdc++-v3/ChangeLog

@@ -1,3 +1,20 @@
+2018-09-03  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/78595
+	* include/bits/stl_map.h (map::insert(_Pair&&))
+	(map::insert(const_iterator, _Pair&&)): Do emplace instead of insert.
+	* include/bits/stl_multimap.h (multimap::insert(_Pair&&))
+	(multimap::insert(const_iterator, _Pair&&)): Likewise.
+	* include/bits/unordered_map.h (unordered_map::insert(_Pair&&))
+	(unordered_map::insert(const_iterator, _Pair&&))
+	(unordered_multimap::insert(_Pair&&))
+	(unordered_multimap::insert(const_iterator, _Pair&&)): Likewise.
+	* testsuite/23_containers/map/modifiers/insert/78595.cc: New test.
+	* testsuite/23_containers/multimap/modifiers/insert/78595.cc: New test.
+	* testsuite/23_containers/unordered_map/modifiers/78595.cc: New test.
+	* testsuite/23_containers/unordered_multimap/modifiers/78595.cc: New
+	test.
+
 2018-09-02  François Dumont  <fdumont@gcc.gnu.org>
 
 	* include/debug/safe_iterator.h

libstdc++-v3/include/bits/stl_map.h

@@ -808,12 +808,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       insert(value_type&& __x)
       { return _M_t._M_insert_unique(std::move(__x)); }
 
-      template<typename _Pair, typename = typename
+      template<typename _Pair>
-	       std::enable_if<std::is_constructible<value_type,
+	__enable_if_t<is_constructible<value_type, _Pair>::value,
-						    _Pair&&>::value>::type>
+		      pair<iterator, bool>>
-	std::pair<iterator, bool>
 	insert(_Pair&& __x)
-	{ return _M_t._M_insert_unique(std::forward<_Pair>(__x)); }
+	{ return _M_t._M_emplace_unique(std::forward<_Pair>(__x)); }
 #endif
       // @}
 
@@ -869,13 +868,13 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       insert(const_iterator __position, value_type&& __x)
       { return _M_t._M_insert_unique_(__position, std::move(__x)); }
 
-      template<typename _Pair, typename = typename
+      template<typename _Pair>
-	       std::enable_if<std::is_constructible<value_type,
+	__enable_if_t<is_constructible<value_type, _Pair>::value, iterator>
-						    _Pair&&>::value>::type>
-	iterator
 	insert(const_iterator __position, _Pair&& __x)
-	{ return _M_t._M_insert_unique_(__position,
+	{
-					std::forward<_Pair>(__x)); }
+	  return _M_t._M_emplace_hint_unique(__position,
+					     std::forward<_Pair>(__x));
+	}
 #endif
       // @}
 

libstdc++-v3/include/bits/stl_multimap.h

@@ -544,12 +544,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       insert(value_type&& __x)
       { return _M_t._M_insert_equal(std::move(__x)); }
 
-      template<typename _Pair, typename = typename
+      template<typename _Pair>
-	       std::enable_if<std::is_constructible<value_type,
+	__enable_if_t<is_constructible<value_type, _Pair>::value, iterator>
-						    _Pair&&>::value>::type>
-	iterator
 	insert(_Pair&& __x)
-	{ return _M_t._M_insert_equal(std::forward<_Pair>(__x)); }
+	{ return _M_t._M_emplace_equal(std::forward<_Pair>(__x)); }
 #endif
       // @}
 
@@ -589,13 +587,13 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       insert(const_iterator __position, value_type&& __x)
       { return _M_t._M_insert_equal_(__position, std::move(__x)); }
 
-      template<typename _Pair, typename = typename
+      template<typename _Pair>
-	       std::enable_if<std::is_constructible<value_type,
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
-						    _Pair&&>::value>::type>
-	iterator
 	insert(const_iterator __position, _Pair&& __x)
-	{ return _M_t._M_insert_equal_(__position,
+	{
-				       std::forward<_Pair>(__x)); }
+	  return _M_t._M_emplace_hint_equal(__position,
+					    std::forward<_Pair>(__x));
+	}
 #endif
       // @}
 

libstdc++-v3/include/bits/unordered_map.h

@@ -585,12 +585,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       insert(value_type&& __x)
       { return _M_h.insert(std::move(__x)); }
 
-      template<typename _Pair, typename = typename
+      template<typename _Pair>
-	       std::enable_if<std::is_constructible<value_type,
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value,
-						    _Pair&&>::value>::type>
+		      pair<iterator, bool>>
-	std::pair<iterator, bool>
 	insert(_Pair&& __x)
-        { return _M_h.insert(std::forward<_Pair>(__x)); }
+        { return _M_h.emplace(std::forward<_Pair>(__x)); }
       //@}
 
       //@{
@@ -625,12 +624,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       insert(const_iterator __hint, value_type&& __x)
       { return _M_h.insert(__hint, std::move(__x)); }
 
-      template<typename _Pair, typename = typename
+      template<typename _Pair>
-	       std::enable_if<std::is_constructible<value_type,
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
-						    _Pair&&>::value>::type>
-	iterator
 	insert(const_iterator __hint, _Pair&& __x)
-	{ return _M_h.insert(__hint, std::forward<_Pair>(__x)); }
+	{ return _M_h.emplace_hint(__hint, std::forward<_Pair>(__x)); }
       //@}
 
       /**
@@ -1571,12 +1568,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       insert(value_type&& __x)
       { return _M_h.insert(std::move(__x)); }
 
-      template<typename _Pair, typename = typename
+      template<typename _Pair>
-	       std::enable_if<std::is_constructible<value_type,
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
-						    _Pair&&>::value>::type>
-	iterator
 	insert(_Pair&& __x)
-        { return _M_h.insert(std::forward<_Pair>(__x)); }
+        { return _M_h.emplace(std::forward<_Pair>(__x)); }
       //@}
 
       //@{
@@ -1609,12 +1604,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       insert(const_iterator __hint, value_type&& __x)
       { return _M_h.insert(__hint, std::move(__x)); }
 
-      template<typename _Pair, typename = typename
+      template<typename _Pair>
-	       std::enable_if<std::is_constructible<value_type,
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
-						    _Pair&&>::value>::type>
-	iterator
 	insert(const_iterator __hint, _Pair&& __x)
-        { return _M_h.insert(__hint, std::forward<_Pair>(__x)); }
+        { return _M_h.emplace_hint(__hint, std::forward<_Pair>(__x)); }
       //@}
 
       /**

libstdc++-v3/testsuite/23_containers/map/modifiers/insert/78595.cc

@@ -0,0 +1,115 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run { target c++11 } }
+
+#include <map>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  struct X {
+    mutable int conversions = 0;
+
+    operator std::pair<const int, int>() const {
+      if (++conversions > 1)
+	throw 1;
+      return {};
+    }
+  };
+
+  std::map<int, int> m;
+  m.insert(X());
+  VERIFY( m.size() == 1 );
+  m.insert(m.begin(), X());
+  VERIFY( m.size() == 1 );
+
+}
+void
+test02()
+{
+  struct Y {
+    int conversions = 0;
+
+    operator std::pair<const int, int>() && {
+      if (++conversions > 1)
+	throw 1;
+      return {};
+    }
+  };
+
+  std::map<int, int> m;
+  m.insert(Y());
+  VERIFY( m.size() == 1 );
+  m.insert(m.begin(), Y());
+  VERIFY( m.size() == 1 );
+}
+
+struct Key {
+  int key;
+  bool operator<(const Key& r) const { return key < r.key; }
+};
+
+struct Z {
+  operator std::pair<const Key, int>() const { return { { z }, 0 }; }
+  int z;
+};
+
+template<typename T>
+struct Alloc
+{
+  Alloc() = default;
+
+  template<typename U>
+    Alloc(const Alloc<U>&) { }
+
+  using value_type = T;
+
+  T* allocate(std::size_t n) { return std::allocator<T>().allocate(n); }
+
+  void deallocate(T* p, std::size_t n) { std::allocator<T>().deallocate(p, n); }
+
+  template<typename U>
+    void construct(U* p, const Z& z) { ::new (p) U{ { z.z+1 }, 0}; }
+
+  template<typename U>
+    bool operator==(const Alloc<U>&) { return true; }
+
+  template<typename U>
+    bool operator!=(const Alloc<U>&) { return false; }
+};
+
+void
+test03()
+{
+  std::map<Key, int, std::less<Key>, Alloc<std::pair<const Key, int>>> m;
+  m.insert(Z{});
+  m.insert(Z{});
+  VERIFY( m.size() == 1 );
+  m.insert(Z{});
+  m.insert(Z{1});
+  VERIFY( m.size() == 2 );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}

libstdc++-v3/testsuite/23_containers/multimap/modifiers/insert/78595.cc

@@ -0,0 +1,115 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run { target c++11 } }
+
+#include <map>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  struct X {
+    mutable int conversions = 0;
+
+    operator std::pair<const int, int>() const {
+      if (++conversions > 1)
+	throw 1;
+      return {};
+    }
+  };
+
+  std::multimap<int, int> m;
+  m.insert(X());
+  VERIFY( m.size() == 1 );
+  m.insert(m.begin(), X());
+  VERIFY( m.size() == 2 );
+
+}
+void
+test02()
+{
+  struct Y {
+    int conversions = 0;
+
+    operator std::pair<const int, int>() && {
+      if (++conversions > 1)
+	throw 1;
+      return {};
+    }
+  };
+
+  std::multimap<int, int> m;
+  m.insert(Y());
+  VERIFY( m.size() == 1 );
+  m.insert(m.begin(), Y());
+  VERIFY( m.size() == 2 );
+}
+
+struct Key {
+  int key;
+  bool operator<(const Key& r) const { return key < r.key; }
+};
+
+struct Z {
+  operator std::pair<const Key, int>() const { return { { z }, 0 }; }
+  int z;
+};
+
+template<typename T>
+struct Alloc
+{
+  Alloc() = default;
+
+  template<typename U>
+    Alloc(const Alloc<U>&) { }
+
+  using value_type = T;
+
+  T* allocate(std::size_t n) { return std::allocator<T>().allocate(n); }
+
+  void deallocate(T* p, std::size_t n) { std::allocator<T>().deallocate(p, n); }
+
+  template<typename U>
+    void construct(U* p, const Z& z) { ::new (p) U{ { z.z+1 }, 0}; }
+
+  template<typename U>
+    bool operator==(const Alloc<U>&) { return true; }
+
+  template<typename U>
+    bool operator!=(const Alloc<U>&) { return false; }
+};
+
+void
+test03()
+{
+  std::multimap<Key, int, std::less<Key>, Alloc<std::pair<const Key, int>>> m;
+  m.insert(Z{});
+  m.insert(Z{});
+  VERIFY( m.size() == 2 );
+  m.insert(Z{});
+  m.insert(Z{1});
+  VERIFY( m.size() == 4 );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}

libstdc++-v3/testsuite/23_containers/unordered_map/modifiers/78595.cc

@@ -0,0 +1,122 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run { target c++11 } }
+
+#include <unordered_map>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  struct X {
+    mutable int conversions = 0;
+
+    operator std::pair<const int, int>() const {
+      if (++conversions > 1)
+	throw 1;
+      return {};
+    }
+  };
+
+  std::unordered_map<int, int> m;
+  m.insert(X());
+  VERIFY( m.size() == 1 );
+  m.insert(m.begin(), X());
+  VERIFY( m.size() == 1 );
+
+}
+void
+test02()
+{
+  struct Y {
+    int conversions = 0;
+
+    operator std::pair<const int, int>() && {
+      if (++conversions > 1)
+	throw 1;
+      return {};
+    }
+  };
+
+  std::unordered_map<int, int> m;
+  m.insert(Y());
+  VERIFY( m.size() == 1 );
+  m.insert(m.begin(), Y());
+  VERIFY( m.size() == 1 );
+}
+
+struct Key {
+  int key;
+  bool operator==(const Key& r) const { return key == r.key; }
+};
+
+namespace std {
+  template<> struct hash<Key> {
+    size_t operator()(const Key& k) const { return std::hash<int>()(k.key); }
+  };
+}
+
+struct Z {
+  operator std::pair<const Key, int>() const { return { { z }, 0 }; }
+  int z;
+};
+
+template<typename T>
+struct Alloc
+{
+  Alloc() = default;
+
+  template<typename U>
+    Alloc(const Alloc<U>&) { }
+
+  using value_type = T;
+
+  T* allocate(std::size_t n) { return std::allocator<T>().allocate(n); }
+
+  void deallocate(T* p, std::size_t n) { std::allocator<T>().deallocate(p, n); }
+
+  template<typename U>
+    void construct(U* p, const Z& z) { ::new (p) U{ { z.z+1 }, 0}; }
+
+  template<typename U>
+    bool operator==(const Alloc<U>&) { return true; }
+
+  template<typename U>
+    bool operator!=(const Alloc<U>&) { return false; }
+};
+
+void
+test03()
+{
+  std::unordered_map<Key, int, std::hash<Key>, std::equal_to<Key>,
+		     Alloc<std::pair<const Key, int>>> m;
+  m.insert(Z{});
+  m.insert(Z{});
+  VERIFY( m.size() == 1 );
+  m.insert(Z{});
+  m.insert(Z{1});
+  VERIFY( m.size() == 2 );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}

libstdc++-v3/testsuite/23_containers/unordered_multimap/modifiers/78595.cc

@@ -0,0 +1,122 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run { target c++11 } }
+
+#include <unordered_map>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  struct X {
+    mutable int conversions = 0;
+
+    operator std::pair<const int, int>() const {
+      if (++conversions > 1)
+	throw 1;
+      return {};
+    }
+  };
+
+  std::unordered_multimap<int, int> m;
+  m.insert(X());
+  VERIFY( m.size() == 1 );
+  m.insert(m.begin(), X());
+  VERIFY( m.size() == 2 );
+
+}
+void
+test02()
+{
+  struct Y {
+    int conversions = 0;
+
+    operator std::pair<const int, int>() && {
+      if (++conversions > 1)
+	throw 1;
+      return {};
+    }
+  };
+
+  std::unordered_multimap<int, int> m;
+  m.insert(Y());
+  VERIFY( m.size() == 1 );
+  m.insert(m.begin(), Y());
+  VERIFY( m.size() == 2 );
+}
+
+struct Key {
+  int key;
+  bool operator==(const Key& r) const { return key == r.key; }
+};
+
+namespace std {
+  template<> struct hash<Key> {
+    size_t operator()(const Key& k) const { return std::hash<int>()(k.key); }
+  };
+}
+
+struct Z {
+  operator std::pair<const Key, int>() const { return { { z }, 0 }; }
+  int z;
+};
+
+template<typename T>
+struct Alloc
+{
+  Alloc() = default;
+
+  template<typename U>
+    Alloc(const Alloc<U>&) { }
+
+  using value_type = T;
+
+  T* allocate(std::size_t n) { return std::allocator<T>().allocate(n); }
+
+  void deallocate(T* p, std::size_t n) { std::allocator<T>().deallocate(p, n); }
+
+  template<typename U>
+    void construct(U* p, const Z& z) { ::new (p) U{ { z.z+1 }, 0}; }
+
+  template<typename U>
+    bool operator==(const Alloc<U>&) { return true; }
+
+  template<typename U>
+    bool operator!=(const Alloc<U>&) { return false; }
+};
+
+void
+test03()
+{
+  std::unordered_multimap<Key, int, std::hash<Key>, std::equal_to<Key>,
+			  Alloc<std::pair<const Key, int>>> m;
+  m.insert(Z{});
+  m.insert(Z{});
+  VERIFY( m.size() == 2 );
+  m.insert(Z{});
+  m.insert(Z{1});
+  VERIFY( m.size() == 4 );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}