This implements remaining changes from P3612R1 Harmonize proxy-reference
operations (LWG 3638 and 4187).
As the const-assigment operator in bitset::reference (from LWG4187)
is used by range concepts (std::indirectly_writable) to recognize
iterator returning it by value as proxy iterator (see range_proxy.cc) test,
this change is backported to C++23. This puts it inline with vector<bool>
reference and other proxy type, for which the coresponding assigment
operator where added by P2321 in C++20 and implemented in r13-2159-g72886f.
Similary, a swap overloads accepting bitset::reference by value and bool&,
are necessary for ranges::swap and ranges::iter_swap to work correctly,
so they should also backported. This patch follows the approach from
resolution of LWG3638 from r12-5311-g59434931fb658f, and backports the
overloads to C++11. This harmonizes the operations on this two proxy
types (per paper title). Corresponding test are added to both classes.
The deprecation warning for static vector<bool>::swap is added sinc C++26.
The text in _GLIBCXX26_DEPRECATED_SUGGEST leads to following message:
'static constexpr void std::vector<bool, _Alloc>::swap(reference, reference)
[with... ]' is deprecated: use 'swap' invoked via ADL or 'std::ranges::swap'
instead
libstdc++-v3/ChangeLog:
* include/bits/stl_bvector.h: Add _GLIBCXX_RESOLVE_LIB_DEFECTS
comment for 3638.
(vector<bool, _Alloc>::swap): Add deprected attribute via
_GLIBCXX26_DEPRECATED_SUGGEST.
* include/std/bitset (bitset::operator=(bool) const)
[__cplusplus > 202002]: Define.
(bistset::reference::swap) [__cplusplus >= 201103L]: Define.
* testsuite/20_util/bitset/access/range_proxy.cc: New test.
* testsuite/20_util/bitset/access/ref_swap.cc: New test.
* testsuite/23_containers/vector/bool/element_access/range_proxy.cc:
New test.
* testsuite/23_containers/vector/bool/element_access/ref_swap.cc:
New test.
* testsuite/23_containers/vector/bool/modifiers/swap/constexpr.cc:
Checkfor deprecated warning on static swap.
---
Do you agree with my backport choice for swap? I think the minimum is
since C++23.
Testing on x86_64-linux. *bitset* and *vector/bool* test already passed
in all standard modes. OK for trunk?
libstdc++-v3/include/bits/stl_bvector.h | 4 +
libstdc++-v3/include/std/bitset | 43 +++++++++
.../20_util/bitset/access/range_proxy.cc | 94 +++++++++++++++++++
.../20_util/bitset/access/ref_swap.cc | 28 ++++++
.../vector/bool/element_access/range_proxy.cc | 62 ++++++++++++
.../vector/bool/element_access/ref_swap.cc | 38 ++++++++
.../vector/bool/modifiers/swap/constexpr.cc | 2 +-
7 files changed, 270 insertions(+), 1 deletion(-)
create mode 100644 libstdc++-v3/testsuite/20_util/bitset/access/range_proxy.cc
create mode 100644 libstdc++-v3/testsuite/20_util/bitset/access/ref_swap.cc
create mode 100644
libstdc++-v3/testsuite/23_containers/vector/bool/element_access/range_proxy.cc
create mode 100644
libstdc++-v3/testsuite/23_containers/vector/bool/element_access/ref_swap.cc
diff --git a/libstdc++-v3/include/bits/stl_bvector.h
b/libstdc++-v3/include/bits/stl_bvector.h
index f190d1be5ce..0637e687cbb 100644
--- a/libstdc++-v3/include/bits/stl_bvector.h
+++ b/libstdc++-v3/include/bits/stl_bvector.h
@@ -149,6 +149,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
{ *_M_p ^= _M_mask; }
#if __cplusplus >= 201103L
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 3638. vector<bool>::swap(reference, reference) is useless
+
_GLIBCXX20_CONSTEXPR
friend void
swap(_Bit_reference __x, _Bit_reference __y) noexcept
@@ -1266,6 +1269,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
}
// [23.2.5]/1, third-to-last entry in synopsis listing
+ _GLIBCXX26_DEPRECATED_SUGGEST("swap' invoked via ADL or
'std::ranges::swap")
_GLIBCXX20_CONSTEXPR
static void
swap(reference __x, reference __y) _GLIBCXX_NOEXCEPT
diff --git a/libstdc++-v3/include/std/bitset b/libstdc++-v3/include/std/bitset
index a8cb337f4b1..a5822319b90 100644
--- a/libstdc++-v3/include/std/bitset
+++ b/libstdc++-v3/include/std/bitset
@@ -908,6 +908,20 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
return *this;
}
+#if __cplusplus > 202002L
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 4187. bitset::reference should be const-assignable
+ constexpr const reference&
+ operator=(bool __x) const noexcept
+ {
+ if (__x)
+ *_M_wp |= _Base::_S_maskbit(_M_bpos);
+ else
+ *_M_wp &= ~_Base::_S_maskbit(_M_bpos);
+ return *this;
+ }
+#endif // C++23
+
// For b[i] = b[__j];
_GLIBCXX23_CONSTEXPR
reference&
@@ -939,6 +953,35 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
*_M_wp ^= _Base::_S_maskbit(_M_bpos);
return *this;
}
+
+#if __cplusplus >= 201103L
+ _GLIBCXX23_CONSTEXPR
+ friend void
+ swap(reference __x, reference __y) noexcept
+ {
+ bool __tmp = __x;
+ __x = __y;
+ __y = __tmp;
+ }
+
+ _GLIBCXX23_CONSTEXPR
+ friend void
+ swap(reference __x, bool& __y) noexcept
+ {
+ bool __tmp = __x;
+ __x = __y;
+ __y = __tmp;
+ }
+
+ _GLIBCXX23_CONSTEXPR
+ friend void
+ swap(bool& __x, reference __y) noexcept
+ {
+ bool __tmp = __x;
+ __x = __y;
+ __y = __tmp;
+ }
+#endif
};
friend class reference;
diff --git a/libstdc++-v3/testsuite/20_util/bitset/access/range_proxy.cc
b/libstdc++-v3/testsuite/20_util/bitset/access/range_proxy.cc
new file mode 100644
index 00000000000..9eac384ce44
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/bitset/access/range_proxy.cc
@@ -0,0 +1,94 @@
+// { dg-do run { target c++20 } }
+
+#include <bitset>
+#include <concepts>
+#include <iterator>
+#include <testsuite_hooks.h>
+
+void
+test_swap()
+{
+ std::bitset<2> v("01");
+ std::ranges::swap(v[0], v[1]);
+ VERIFY( v[0] == false );
+ VERIFY( v[1] == true );
+
+ bool b = true;
+ std::ranges::swap(v[0], b);
+ VERIFY( v[0] == true );
+ VERIFY( b == false );
+
+ std::ranges::swap(b, v[1]);
+ VERIFY( v[1] == false );
+ VERIFY( b == true );
+}
+
+template<size_t N>
+struct bitset_iterator
+{
+ using value_type = bool;
+ using reference = std::bitset<2>::reference;
+ using iterator_category = std::forward_iterator_tag;
+ using difference_type = std::ptrdiff_t;
+
+ bitset_iterator() = default;
+ bitset_iterator(std::bitset<N>& c) noexcept : cont(&c) {}
+
+ reference operator*() const noexcept
+ { return (*cont)[pos]; }
+
+ bitset_iterator& operator++() {
+ ++pos;
+ return *this;
+ }
+
+ bitset_iterator operator++(int) {
+ auto tmp = *this;
+ ++pos;
+ return *this;
+ };
+
+ friend bool operator==(bitset_iterator, bitset_iterator) = default;
+
+private:
+ std::bitset<N>* cont = nullptr;
+ size_t pos = 0;
+};
+
+void
+test_iter_swap()
+{
+ std::bitset<2> v("01");
+ auto it1 = bitset_iterator<2>(v);
+ auto it2 = std::ranges::next(it1);
+ std::ranges::iter_swap(it1, it2);
+ VERIFY( v[0] == false );
+ VERIFY( v[1] == true );
+
+ bool b = true, *p = &b;
+ std::ranges::iter_swap(it1, p);
+ VERIFY( v[0] == true );
+ VERIFY( b == false );
+
+ std::ranges::iter_swap(p, it2);
+ VERIFY( v[1] == false );
+ VERIFY( b == true );
+}
+
+#if __cplusplus > 202002L
+static_assert( std::indirectly_writable<bitset_iterator<2>, bool> );
+static_assert( std::indirectly_writable<bitset_iterator<2>,
+ std::bitset<2>::reference> );
+
+#else
+static_assert( !std::indirectly_writable<bitset_iterator<2>, bool> );
+static_assert( !std::indirectly_writable<bitset_iterator<2>,
+ std::bitset<2>::reference> );
+#endif
+
+int
+main()
+{
+ test_swap();
+ test_iter_swap();
+}
diff --git a/libstdc++-v3/testsuite/20_util/bitset/access/ref_swap.cc
b/libstdc++-v3/testsuite/20_util/bitset/access/ref_swap.cc
new file mode 100644
index 00000000000..1d8e3c1bf49
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/bitset/access/ref_swap.cc
@@ -0,0 +1,28 @@
+// { dg-do run { target c++11 } }
+
+#include <bitset>
+#include <testsuite_hooks.h>
+
+void
+test_friend()
+{
+ std::bitset<2> v("01");
+ swap(v[0], v[1]);
+ VERIFY( v[0] == false );
+ VERIFY( v[1] == true );
+
+ bool b = true;
+ swap(v[0], b);
+ VERIFY( v[0] == true );
+ VERIFY( b == false );
+
+ swap(b, v[1]);
+ VERIFY( v[1] == false );
+ VERIFY( b == true );
+}
+
+int
+main()
+{
+ test_friend();
+}
diff --git
a/libstdc++-v3/testsuite/23_containers/vector/bool/element_access/range_proxy.cc
b/libstdc++-v3/testsuite/23_containers/vector/bool/element_access/range_proxy.cc
new file mode 100644
index 00000000000..075132034f1
--- /dev/null
+++
b/libstdc++-v3/testsuite/23_containers/vector/bool/element_access/range_proxy.cc
@@ -0,0 +1,62 @@
+// { dg-do run { target c++20 } }
+
+#include <vector>
+#include <concepts>
+#include <iterator>
+#include <testsuite_hooks.h>
+
+void
+test_swap()
+{
+ std::vector<bool> v{true, false};
+ std::ranges::swap(v[0], v[1]);
+ VERIFY( v[0] == false );
+ VERIFY( v[1] == true );
+
+ bool b = true;
+ std::ranges::swap(v[0], b);
+ VERIFY( v[0] == true );
+ VERIFY( b == false );
+
+ std::ranges::swap(b, v[1]);
+ VERIFY( v[1] == false );
+ VERIFY( b == true );
+}
+
+void
+test_iter_swap()
+{
+ std::vector<bool> v{true, false};
+ auto it1 = v.begin();
+ auto it2 = std::ranges::next(it1);
+ std::ranges::iter_swap(it1, it2);
+ VERIFY( v[0] == false );
+ VERIFY( v[1] == true );
+
+ bool b = true, *p = &b;
+ std::ranges::iter_swap(it1, p);
+ VERIFY( v[0] == true );
+ VERIFY( b == false );
+
+ std::ranges::iter_swap(p, it2);
+ VERIFY( v[1] == false );
+ VERIFY( b == true );
+}
+
+#if __cplusplus > 202002L
+static_assert( std::indirectly_writable<std::vector<bool>::iterator, bool> );
+static_assert( std::indirectly_writable<std::vector<bool>::iterator,
+ std::vector<bool>::reference> );
+
+#else
+static_assert( !std::indirectly_writable<std::vector<bool>::iterator, bool> );
+static_assert( !std::indirectly_writable<std::vector<bool>::iterator,
+ std::vector<bool>::reference> );
+#endif
+
+int
+main()
+{
+ test_swap();
+ test_iter_swap();
+}
diff --git
a/libstdc++-v3/testsuite/23_containers/vector/bool/element_access/ref_swap.cc
b/libstdc++-v3/testsuite/23_containers/vector/bool/element_access/ref_swap.cc
new file mode 100644
index 00000000000..2221e3b03f0
--- /dev/null
+++
b/libstdc++-v3/testsuite/23_containers/vector/bool/element_access/ref_swap.cc
@@ -0,0 +1,38 @@
+// { dg-do run { target c++11 } }
+
+#include <vector>
+#include <testsuite_hooks.h>
+
+void
+test_friend()
+{
+ std::vector<bool> v{true, false};
+ swap(v[0], v[1]);
+ VERIFY( v[0] == false );
+ VERIFY( v[1] == true );
+
+ bool b = true;
+ swap(v[0], b);
+ VERIFY( v[0] == true );
+ VERIFY( b == false );
+
+ swap(b, v[1]);
+ VERIFY( v[1] == false );
+ VERIFY( b == true );
+}
+
+void
+test_static()
+{
+ std::vector<bool> v{true, false};
+ std::vector<bool>::swap(v[0], v[1]); // { dg-warning "deprecated" "::swap" {
target c++26 } }
+ VERIFY( v[0] == false );
+ VERIFY( v[1] == true );
+}
+
+int
+main()
+{
+ test_friend();
+ test_static();
+}
diff --git
a/libstdc++-v3/testsuite/23_containers/vector/bool/modifiers/swap/constexpr.cc
b/libstdc++-v3/testsuite/23_containers/vector/bool/modifiers/swap/constexpr.cc
index d2a0218a109..1eb526800f7 100644
---
a/libstdc++-v3/testsuite/23_containers/vector/bool/modifiers/swap/constexpr.cc
+++
b/libstdc++-v3/testsuite/23_containers/vector/bool/modifiers/swap/constexpr.cc
@@ -53,7 +53,7 @@ constexpr bool
test_reference_swap()
{
std::vector<bool> v1 = {true, false, true};
- std::vector<bool>::swap(v1[0], v1[1]);
+ std::vector<bool>::swap(v1[0], v1[1]); // { dg-warning "deprecated" "::swap"
{ target c++26 } }
VERIFY(v1[0] == false);
VERIFY(v1[1] == true);
--
2.54.0
