libstdc++: Fix flat_foo::insert_range for non-common ranges [PR118156]

This fixes flat_map/multimap::insert_range by just generalizing the
insert implementation to handle heterogenous iterator/sentinel pair.
I'm not sure we can do better than this, e.g. we can't implement it in
terms of the adapted containers' insert_range because that'd require two
passes over the range.

For flat_set/multiset, we can implement insert_range directly in terms
of the adapted container's insert_range.  A fallback implementation
is also provided if insert_range isn't available, as is the case for
std::deque currently.

	PR libstdc++/118156

libstdc++-v3/ChangeLog:

	* include/std/flat_map (_Flat_map_impl::_M_insert): Generalized
	version of insert taking heterogenous iterator/sentinel pair.
	(_Flat_map_impl::insert): Dispatch to _M_insert.
	(_Flat_map_impl::insert_range): Likewise.
	(flat_map): Export _Flat_map_impl::insert_range.
	(flat_multimap): Likewise.
	* include/std/flat_set (_Flat_set_impl::insert_range):
	Reimplement directly, not in terms of insert.
	(flat_set): Export _Flat_set_impl::insert_range.
	(flat_multiset): Likewise.
	* testsuite/23_containers/flat_map/1.cc (test06): New test.
	* testsuite/23_containers/flat_multimap/1.cc (test06): New test.
	* testsuite/23_containers/flat_multiset/1.cc (test06): New test.
	* testsuite/23_containers/flat_set/1.cc (test06): New test.

Reviewed-by: Jonathan Wakely <jwakely@redhat.com>

6 files changed, 101 insertions, 8 deletions

diff --git a/libstdc++-v3/include/std/flat_map b/libstdc++-v3/include/std/flat_map
index 1ecc2e7..405caa8 100644
--- a/libstdc++-v3/include/std/flat_map
+++ b/libstdc++-v3/include/std/flat_map
@@ -538,9 +538,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	insert(const_iterator __position, _Arg&& __x)
 	{ return emplace_hint(__position, std::forward<_Arg>(__x)); }
 
-      template<__has_input_iter_cat _InputIterator>
+    private:
+      template<typename _Iter, typename _Sent>
 	void
-	insert(_InputIterator __first, _InputIterator __last)
+	_M_insert(_Iter __first, _Sent __last)
 	{
 	  // FIXME: This implementation fails its complexity requirements.
 	  // We can't idiomatically implement an efficient version (as in the
@@ -574,6 +575,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #endif
 	}
 
+    public:
+      template<__has_input_iter_cat _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_insert(std::move(__first), std::move(__last)); }
+
       template<__has_input_iter_cat _InputIterator>
 	void
 	insert(__sorted_t, _InputIterator __first, _InputIterator __last)
@@ -585,7 +592,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       template<__detail::__container_compatible_range<value_type> _Rg>
 	void
 	insert_range(_Rg&& __rg)
-	{ insert(ranges::begin(__rg), ranges::end(__rg)); }
+	{ _M_insert(ranges::begin(__rg), ranges::end(__rg)); }
 
       void
       insert(initializer_list<value_type> __il)
@@ -1181,7 +1188,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       using _Impl::emplace;
       using _Impl::emplace_hint;
       using _Impl::insert;
-      // using _Impl::insert_range;
+      using _Impl::insert_range;
       using _Impl::extract;
       using _Impl::replace;
       using _Impl::erase;
@@ -1460,7 +1467,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       using _Impl::emplace;
       using _Impl::emplace_hint;
       using _Impl::insert;
-      // using _Impl::insert_range;
+      using _Impl::insert_range;
       using _Impl::extract;
       using _Impl::replace;
       using _Impl::erase;
diff --git a/libstdc++-v3/include/std/flat_set b/libstdc++-v3/include/std/flat_set
index 3e1347a..9240f2b 100644
--- a/libstdc++-v3/include/std/flat_set
+++ b/libstdc++-v3/include/std/flat_set
@@ -475,7 +475,28 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       template<__detail::__container_compatible_range<value_type> _Rg>
 	void
 	insert_range(_Rg&& __rg)
-	{ insert(ranges::begin(__rg), ranges::end(__rg)); }
+	{
+	  auto __guard = _M_make_clear_guard();
+	  typename container_type::iterator __it;
+	  if constexpr (requires { _M_cont.insert_range(_M_cont.end(), __rg); })
+	    __it = _M_cont.insert_range(_M_cont.end(), __rg);
+	  else if constexpr (ranges::common_range<_Rg>)
+	    __it = _M_cont.insert(_M_cont.end(), ranges::begin(__rg), ranges::end(__rg));
+	  else
+	    {
+	      size_type __n = size();
+	      auto __first = ranges::begin(__rg);
+	      auto __last = ranges::end(__rg);
+	      for (; __first != __last; ++__first)
+		_M_cont.emplace_back(*__first);
+	      __it = _M_cont.begin() + __n;
+	    }
+	  std::sort(__it, _M_cont.end(), _M_comp);
+	  std::inplace_merge(_M_cont.begin(), __it, _M_cont.end(), _M_comp);
+	  if constexpr (!_Multi)
+	    _M_unique();
+	  __guard._M_disable();
+	}
 
       void
       insert(initializer_list<value_type> __il)
@@ -808,7 +829,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       using _Impl::emplace;
       using _Impl::emplace_hint;
       using _Impl::insert;
-      // using _Impl::insert_range;
+      using _Impl::insert_range;
       using _Impl::extract;
       using _Impl::replace;
       using _Impl::erase;
@@ -947,7 +968,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       using _Impl::emplace;
       using _Impl::emplace_hint;
       using _Impl::insert;
-      // using _Impl::insert_range;
+      using _Impl::insert_range;
       using _Impl::extract;
       using _Impl::replace;
       using _Impl::erase;
diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
index 111cafa..00254dc 100644
--- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
@@ -164,6 +164,22 @@ test05()
   VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, -4, -5}) );
 }
 
+void
+test06()
+{
+  // PR libstdc++/118156 - flat_foo::insert_range cannot handle non-common ranges
+  std::flat_map<int, int> m;
+  auto r = std::views::zip(std::views::iota(1), std::views::iota(2)) | std::views::take(5);
+  static_assert(!std::ranges::common_range<decltype(r)>);
+  m.insert_range(r);
+  VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 4, 5}) );
+  VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
+  m.clear();
+  m.insert_range(r | std::views::reverse);
+  VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 4, 5}) );
+  VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
+}
+
 int
 main()
 {
@@ -175,4 +191,5 @@ main()
   test03();
   test04();
   test05();
+  test06();
 }
diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
index 08f4bbc..38650a8 100644
--- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
@@ -138,6 +138,21 @@ test05()
   VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 3, 4, 5}) );
   VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, 3, -4, -5}) );
 }
+void
+test06()
+{
+  // PR libstdc++/118156 - flat_foo::insert_range cannot handle non-common ranges
+  std::flat_multimap<int, int> m;
+  auto r = std::views::zip(std::views::iota(1), std::views::iota(2)) | std::views::take(5);
+  static_assert(!std::ranges::common_range<decltype(r)>);
+  m.insert_range(r);
+  VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 4, 5}) );
+  VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
+  m.clear();
+  m.insert_range(r | std::views::reverse);
+  VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 4, 5}) );
+  VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
+}
 
 int
 main()
@@ -150,4 +165,5 @@ main()
   test03();
   test04();
   test05();
+  test06();
 }
diff --git a/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
index 82958f7..910f5dc 100644
--- a/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
@@ -2,6 +2,7 @@
 
 #include <flat_set>
 #include <deque>
+#include <ranges>
 #include <vector>
 #include <testsuite_allocator.h>
 #include <testsuite_hooks.h>
@@ -128,6 +129,20 @@ test05()
   VERIFY( std::ranges::equal(m, (int[]){1, 2, 3, 3, 4, 5}) );
 }
 
+void
+test06()
+{
+  // PR libstdc++/118156 - flat_foo::insert_range cannot handle non-common ranges
+  std::flat_multiset<int> s;
+  auto r = std::views::iota(1) | std::views::take(5);
+  static_assert(!std::ranges::common_range<decltype(r)>);
+  s.insert_range(r);
+  VERIFY( std::ranges::equal(s, (int[]){1, 2, 3, 4, 5}) );
+  s.clear();
+  s.insert_range(r | std::views::reverse);
+  VERIFY( std::ranges::equal(s, (int[]){1, 2, 3, 4, 5}) );
+}
+
 int
 main()
 {
@@ -137,4 +152,5 @@ main()
   test03();
   test04();
   test05();
+  test06();
 }
diff --git a/libstdc++-v3/testsuite/23_containers/flat_set/1.cc b/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
index 325b126..f0eaac9 100644
--- a/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
@@ -7,6 +7,7 @@
 #endif
 
 #include <deque>
+#include <ranges>
 #include <vector>
 #include <testsuite_allocator.h>
 #include <testsuite_hooks.h>
@@ -143,6 +144,20 @@ test05()
   VERIFY( std::ranges::equal(m, (int[]){1, 2, 3, 4, 5}) );
 }
 
+void
+test06()
+{
+  // PR libstdc++/118156 - flat_foo::insert_range cannot handle non-common ranges
+  std::flat_set<int> s;
+  auto r = std::views::iota(1) | std::views::take(5);
+  static_assert(!std::ranges::common_range<decltype(r)>);
+  s.insert_range(r);
+  VERIFY( std::ranges::equal(s, (int[]){1, 2, 3, 4, 5}) );
+  s.clear();
+  s.insert_range(r | std::views::reverse);
+  VERIFY( std::ranges::equal(s, (int[]){1, 2, 3, 4, 5}) );
+}
+
 int
 main()
 {
@@ -152,4 +167,5 @@ main()
   test03();
   test04();
   test05();
+  test06();
 }