Support allocators in tuples of zero size.

	* include/std/tuple (tuple<>::tuple(),
	tuple<>::tuple(allocator_arg_t, const _Alloc&),
	tuple<>::tuple(allocator_arg_t, const _Alloc&, const tuple&)): New.
	* testsuite/20_util/tuple/cons/allocators.cc: Adjust.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@237143 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 22 insertions, 0 deletions

diff --git a/libstdc++-v3/testsuite/20_util/tuple/cons/allocators.cc b/libstdc++-v3/testsuite/20_util/tuple/cons/allocators.cc
index 052b79fcf83..bc45780cb98 100644
--- a/libstdc++-v3/testsuite/20_util/tuple/cons/allocators.cc
+++ b/libstdc++-v3/testsuite/20_util/tuple/cons/allocators.cc
@@ -162,8 +162,30 @@ void test01()
 
 }
 
+void test02()
+{
+  bool test __attribute__((unused)) = true;
+  using std::allocator_arg;
+  using std::tuple;
+  using std::make_tuple;
+
+  typedef tuple<> test_type;
+
+  MyAlloc a;
+
+  // default construction
+  test_type t1(allocator_arg, a);
+  // copy construction
+  test_type t2(allocator_arg, a, t1);
+  // move construction
+  test_type t3(allocator_arg, a, std::move(t1));
+  // make_tuple
+  test_type empty = make_tuple();
+}
+
 int main()
 {
   test01();
+  test02();
   return 0;
 }