From: Patrick Palka <ppalka@redhat.com>
Date: Wed, 22 Jan 2020 21:51:19 +0000 (-0500)
Subject: libstdc++: Apply the move_iterator changes described in P1207R4
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=7db12d155ddf4b5d7a5e783a97995f85e19e88dd;p=gcc.git

libstdc++: Apply the move_iterator changes described in P1207R4

These changes are needed for some of the tests in the constrained algorithm
patch, because they use move_iterator with an uncopyable output_iterator.  The
other changes described in the paper are already applied, it seems.

libstdc++-v3/ChangeLog:

	* include/bits/stl_iterator.h (move_iterator::move_iterator): Move __i
	when initializing _M_current.
	(move_iterator::base): Split into two overloads differing in
	ref-qualifiers as in P1207R4 for C++20.
---

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index d925a0b3de8..b54f1f694e4 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,10 @@
+2020-02-05  Patrick Palka  <ppalka@redhat.com>
+
+	* include/bits/stl_iterator.h (move_iterator::move_iterator): Move __i
+	when initializing _M_current.
+	(move_iterator::base): Split into two overloads differing in
+	ref-qualifiers as in P1207R4 for C++20.
+
 2020-02-04  Jonathan Wakely  <jwakely@redhat.com>
 
 	* include/std/functional (_GLIBCXX_NOT_FN_CALL_OP): Un-define after
diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
index 784d200d22f..c200f7a9d14 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -1166,16 +1166,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       explicit _GLIBCXX17_CONSTEXPR
       move_iterator(iterator_type __i)
-      : _M_current(__i) { }
+      : _M_current(std::move(__i)) { }
 
       template<typename _Iter>
 	_GLIBCXX17_CONSTEXPR
 	move_iterator(const move_iterator<_Iter>& __i)
 	: _M_current(__i.base()) { }
 
+#if __cplusplus <= 201703L
       _GLIBCXX17_CONSTEXPR iterator_type
       base() const
       { return _M_current; }
+#else
+      constexpr iterator_type
+      base() const &
+#if __cpp_lib_concepts
+	requires copy_constructible<iterator_type>
+#endif
+      { return _M_current; }
+
+      constexpr iterator_type
+      base() &&
+      { return std::move(_M_current); }
+#endif
 
       _GLIBCXX17_CONSTEXPR reference
       operator*() const