Make sure that __libcpp_compressed_pair_imp default-constructs its' members, rather than value-initializing them. Fixes PR#24137

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@242377 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/memory b/include/memory
index 9c1eef7..22311aa 100644
--- a/include/memory
+++ b/include/memory
@@ -2035,11 +2035,11 @@
     typedef const typename remove_reference<_T1>::type& _T1_const_reference;
     typedef const typename remove_reference<_T2>::type& _T2_const_reference;
 
-    _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp() {}
+    _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp() : __first_(), __second_() {}
     _LIBCPP_INLINE_VISIBILITY explicit __libcpp_compressed_pair_imp(_T1_param __t1)
-        : __first_(_VSTD::forward<_T1_param>(__t1)) {}
+        : __first_(_VSTD::forward<_T1_param>(__t1)), __second_() {}
     _LIBCPP_INLINE_VISIBILITY explicit __libcpp_compressed_pair_imp(_T2_param __t2)
-        : __second_(_VSTD::forward<_T2_param>(__t2)) {}
+        : __first_(), __second_(_VSTD::forward<_T2_param>(__t2)) {}
     _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp(_T1_param __t1, _T2_param __t2)
         : __first_(_VSTD::forward<_T1_param>(__t1)), __second_(_VSTD::forward<_T2_param>(__t2)) {}
 
@@ -2128,9 +2128,9 @@
     typedef const _T1&                                        _T1_const_reference;
     typedef const typename remove_reference<_T2>::type& _T2_const_reference;
 
-    _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp() {}
+    _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp() : __second_() {}
     _LIBCPP_INLINE_VISIBILITY explicit __libcpp_compressed_pair_imp(_T1_param __t1)
-        : _T1(_VSTD::forward<_T1_param>(__t1)) {}
+        : _T1(_VSTD::forward<_T1_param>(__t1)), __second_() {}
     _LIBCPP_INLINE_VISIBILITY explicit __libcpp_compressed_pair_imp(_T2_param __t2)
         : __second_(_VSTD::forward<_T2_param>(__t2)) {}
     _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp(_T1_param __t1, _T2_param __t2)
@@ -2218,11 +2218,11 @@
     typedef const typename remove_reference<_T1>::type& _T1_const_reference;
     typedef const _T2&                                        _T2_const_reference;
 
-    _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp() {}
+    _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp() : __first_() {}
     _LIBCPP_INLINE_VISIBILITY explicit __libcpp_compressed_pair_imp(_T1_param __t1)
         : __first_(_VSTD::forward<_T1_param>(__t1)) {}
     _LIBCPP_INLINE_VISIBILITY explicit __libcpp_compressed_pair_imp(_T2_param __t2)
-        : _T2(_VSTD::forward<_T2_param>(__t2)) {}
+        : _T2(_VSTD::forward<_T2_param>(__t2)), __first_() {}
     _LIBCPP_INLINE_VISIBILITY __libcpp_compressed_pair_imp(_T1_param __t1, _T2_param __t2)
         _NOEXCEPT_(is_nothrow_move_constructible<_T1>::value &&
                    is_nothrow_move_constructible<_T2>::value)