[gcc/devel/omp/gcc-9] Implement missing piece of P0777R1 for std::make_from_tuple

[Tobias Burnus]

https://gcc.gnu.org/g:2a4405e3ba37ce0f0c8c479235ecbd87649f93fa

commit 2a4405e3ba37ce0f0c8c479235ecbd87649f93fa
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Jun 3 15:05:46 2019 +0100

    Implement missing piece of P0777R1 for std::make_from_tuple
    
    	* include/std/tuple (make_from_tuple): Use remove_reference_t instead
    	of decay_t (P0777R1).
    
    From-SVN: r271871

Diff:
---
 libstdc++-v3/ChangeLog         | 5 +++++
 libstdc++-v3/include/std/tuple | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 48cc1d8..182660c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2019-06-03  Jonathan Wakely  <jwakely@redhat.com>
+
+	* include/std/tuple (make_from_tuple): Use remove_reference_t instead
+	of decay_t (P0777R1).
+
 2019-05-30  Jonathan Wakely  <jwakely@redhat.com>
 
 	* doc/xml/manual/status_cxx2017.xml: Fix typo in documentation of
diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index 6c7d91b..bc0b1ad 100644
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -1709,7 +1709,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
       return __make_from_tuple_impl<_Tp>(
         std::forward<_Tuple>(__t),
-	make_index_sequence<tuple_size_v<decay_t<_Tuple>>>{});
+	make_index_sequence<tuple_size_v<remove_reference_t<_Tuple>>>{});
     }
 #endif // C++17