[gcc r10-7005] libstdc++: Move-only input iterator support in <memory> algorithms (LWG 3355)
Patrick Palka
ppalka@gcc.gnu.org
Wed Mar 4 03:49:00 GMT 2020
https://gcc.gnu.org/g:144dfc68d0c0f5b99a0cd0a14b211f82afed88c6
commit r10-7005-g144dfc68d0c0f5b99a0cd0a14b211f82afed88c6
Author: Patrick Palka <ppalka@redhat.com>
Date: Mon Mar 2 19:39:46 2020 -0500
libstdc++: Move-only input iterator support in <memory> algorithms (LWG 3355)
This adds support for move-only input iterators in the ranges::unitialized_*
algorithms defined in <memory>, as per LWG 3355. The only changes needed are to
add calls to std::move in the appropriate places and to use operator- instead of
ranges::distance because the latter cannot be used with a move-only iterator
that has a sized sentinel, as is the case here. (This issue with
ranges::distance is LWG 3392.)
libstdc++-v3/ChangeLog:
LWG 3355 The memory algorithms should support move-only input iterators
introduced by P1207
* include/bits/ranges_uninitialized.h
(__uninitialized_copy_fn::operator()): Use std::move to avoid attempting
to copy __ifirst, which could be a move-only input iterator. Use
operator- instead of ranges::distance to compute distance from a sized
sentinel.
(__uninitialized_copy_n_fn::operator()): Likewise.
(__uninitialized_move_fn::operator()): Likewise.
(__uninitialized_move_n_fn::operator()): Likewise.
(__uninitialized_destroy_fn::operator()): Use std::move to avoid
attempting to copy __first.
(__uninitialized_destroy_n_fn::operator()): Likewise.
* testsuite/20_util/specialized_algorithms/destroy/constrained.cc:
Augment test.
* .../specialized_algorithms/uninitialized_copy/constrained.cc:
Likewise.
* .../specialized_algorithms/uninitialized_move/constrained.cc:
Likewise.
Diff:
---
libstdc++-v3/ChangeLog | 20 +++++++++++++
libstdc++-v3/include/bits/ranges_uninitialized.h | 34 ++++++++++++----------
.../specialized_algorithms/destroy/constrained.cc | 15 ++++++++++
.../uninitialized_copy/constrained.cc | 25 ++++++++++++++++
.../uninitialized_move/constrained.cc | 25 ++++++++++++++++
5 files changed, 103 insertions(+), 16 deletions(-)
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index ca5f0d0..3e4e58c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,25 @@
2020-03-04 Patrick Palka <ppalka@redhat.com>
+ LWG 3355 The memory algorithms should support move-only input iterators
+ introduced by P1207
+ * include/bits/ranges_uninitialized.h
+ (__uninitialized_copy_fn::operator()): Use std::move to avoid attempting
+ to copy __ifirst, which could be a move-only input iterator. Use
+ operator- instead of ranges::distance to compute distance from a sized
+ sentinel.
+ (__uninitialized_copy_n_fn::operator()): Likewise.
+ (__uninitialized_move_fn::operator()): Likewise.
+ (__uninitialized_move_n_fn::operator()): Likewise.
+ (__uninitialized_destroy_fn::operator()): Use std::move to avoid
+ attempting to copy __first.
+ (__uninitialized_destroy_n_fn::operator()): Likewise.
+ * testsuite/20_util/specialized_algorithms/destroy/constrained.cc:
+ Augment test.
+ * .../specialized_algorithms/uninitialized_copy/constrained.cc:
+ Likewise.
+ * .../specialized_algorithms/uninitialized_move/constrained.cc:
+ Likewise.
+
* testsuite/util/testsuite_iterators.h (test_range::get_iterator): Make
protected instead of private.
(test_sized_range_sized_sent): New.
diff --git a/libstdc++-v3/include/bits/ranges_uninitialized.h b/libstdc++-v3/include/bits/ranges_uninitialized.h
index f97a07a..d758078 100644
--- a/libstdc++-v3/include/bits/ranges_uninitialized.h
+++ b/libstdc++-v3/include/bits/ranges_uninitialized.h
@@ -272,9 +272,10 @@ namespace ranges
&& is_nothrow_assignable_v<_OutType&,
iter_reference_t<_Iter>>)
{
- auto __d1 = ranges::distance(__ifirst, __ilast);
- auto __d2 = ranges::distance(__ofirst, __olast);
- return ranges::copy_n(__ifirst, std::min(__d1, __d2), __ofirst);
+ auto __d1 = __ilast - __ifirst;
+ auto __d2 = __olast - __ofirst;
+ return ranges::copy_n(std::move(__ifirst), std::min(__d1, __d2),
+ __ofirst);
}
else
{
@@ -283,7 +284,7 @@ namespace ranges
++__ofirst, (void)++__ifirst)
::new (__detail::__voidify(*__ofirst)) _OutType(*__ifirst);
__guard.release();
- return {__ifirst, __ofirst};
+ return {std::move(__ifirst), __ofirst};
}
}
@@ -319,8 +320,9 @@ namespace ranges
&& is_nothrow_assignable_v<_OutType&,
iter_reference_t<_Iter>>)
{
- auto __d = ranges::distance(__ofirst, __olast);
- return ranges::copy_n(__ifirst, std::min(__n, __d), __ofirst);
+ auto __d = __olast - __ofirst;
+ return ranges::copy_n(std::move(__ifirst), std::min(__n, __d),
+ __ofirst);
}
else
{
@@ -329,7 +331,7 @@ namespace ranges
++__ofirst, (void)++__ifirst, (void)--__n)
::new (__detail::__voidify(*__ofirst)) _OutType(*__ifirst);
__guard.release();
- return {__ifirst, __ofirst};
+ return {std::move(__ifirst), __ofirst};
}
}
};
@@ -357,10 +359,10 @@ namespace ranges
&& is_nothrow_assignable_v<_OutType&,
iter_rvalue_reference_t<_Iter>>)
{
- auto __d1 = ranges::distance(__ifirst, __ilast);
- auto __d2 = ranges::distance(__ofirst, __olast);
+ auto __d1 = __ilast - __ifirst;
+ auto __d2 = __olast - __ofirst;
auto [__in, __out]
- = ranges::copy_n(std::make_move_iterator(__ifirst),
+ = ranges::copy_n(std::make_move_iterator(std::move(__ifirst)),
std::min(__d1, __d2), __ofirst);
return {std::move(__in).base(), __out};
}
@@ -372,7 +374,7 @@ namespace ranges
::new (__detail::__voidify(*__ofirst))
_OutType(ranges::iter_move(__ifirst));
__guard.release();
- return {__ifirst, __ofirst};
+ return {std::move(__ifirst), __ofirst};
}
}
@@ -409,9 +411,9 @@ namespace ranges
&& is_nothrow_assignable_v<_OutType&,
iter_rvalue_reference_t<_Iter>>)
{
- auto __d = ranges::distance(__ofirst, __olast);
+ auto __d = __olast - __ofirst;
auto [__in, __out]
- = ranges::copy_n(std::make_move_iterator(__ifirst),
+ = ranges::copy_n(std::make_move_iterator(std::move(__ifirst)),
std::min(__n, __d), __ofirst);
return {std::move(__in).base(), __out};
}
@@ -423,7 +425,7 @@ namespace ranges
::new (__detail::__voidify(*__ofirst))
_OutType(ranges::iter_move(__ifirst));
__guard.release();
- return {__ifirst, __ofirst};
+ return {std::move(__ifirst), __ofirst};
}
}
};
@@ -524,7 +526,7 @@ namespace ranges
__destroy_fn::operator()(_Iter __first, _Sent __last) const noexcept
{
if constexpr (is_trivially_destructible_v<iter_value_t<_Iter>>)
- return ranges::next(__first, __last);
+ return ranges::next(std::move(__first), __last);
else
{
for (; __first != __last; ++__first)
@@ -549,7 +551,7 @@ namespace ranges
operator()(_Iter __first, iter_difference_t<_Iter> __n) const noexcept
{
if constexpr (is_trivially_destructible_v<iter_value_t<_Iter>>)
- return ranges::next(__first, __n);
+ return ranges::next(std::move(__first), __n);
else
{
for (; __n > 0; ++__first, (void)--__n)
diff --git a/libstdc++-v3/testsuite/20_util/specialized_algorithms/destroy/constrained.cc b/libstdc++-v3/testsuite/20_util/specialized_algorithms/destroy/constrained.cc
index c04049d..89085d3 100644
--- a/libstdc++-v3/testsuite/20_util/specialized_algorithms/destroy/constrained.cc
+++ b/libstdc++-v3/testsuite/20_util/specialized_algorithms/destroy/constrained.cc
@@ -29,6 +29,9 @@
#include <testsuite_hooks.h>
#include <testsuite_iterators.h>
+using __gnu_test::test_range;
+using __gnu_test::input_iterator_wrapper_nocopy;
+
namespace ranges = std::ranges;
struct X
@@ -69,6 +72,18 @@ test01()
}
}
+void
+test02()
+{
+ // LWG 3355
+ {
+ int x[3] = {0};
+ test_range<int, input_iterator_wrapper_nocopy> rx(x);
+ ranges::destroy(rx);
+ ranges::destroy_n(rx.begin(), 3);
+ }
+}
+
int
main()
{
diff --git a/libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_copy/constrained.cc b/libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_copy/constrained.cc
index c1a50c4..ac5d745 100644
--- a/libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_copy/constrained.cc
+++ b/libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_copy/constrained.cc
@@ -31,6 +31,9 @@
using __gnu_test::test_input_range;
using __gnu_test::test_forward_range;
+using __gnu_test::test_range;
+using __gnu_test::test_sized_range_sized_sent;
+using __gnu_test::input_iterator_wrapper_nocopy;
namespace ranges = std::ranges;
@@ -150,6 +153,28 @@ test02()
}
}
+void
+test03()
+{
+ // LWG 3355
+ {
+ int x[3] = {0};
+ int y[3];
+ test_sized_range_sized_sent<int, input_iterator_wrapper_nocopy> rx(x);
+ ranges::uninitialized_copy(rx, y);
+ ranges::uninitialized_copy_n(rx.begin(), 3, y, y+3);
+ }
+
+ {
+ int x[3] = {0};
+ int y[3];
+ test_range<int, input_iterator_wrapper_nocopy> rx(x);
+ test_forward_range<int> ry(y);
+ ranges::uninitialized_copy(rx, y);
+ ranges::uninitialized_copy_n(rx.begin(), 3, ry.begin(), ry.end());
+ }
+}
+
int
main()
{
diff --git a/libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_move/constrained.cc b/libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_move/constrained.cc
index a7d6fd3..6b3544e 100644
--- a/libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_move/constrained.cc
+++ b/libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_move/constrained.cc
@@ -31,6 +31,9 @@
using __gnu_test::test_input_range;
using __gnu_test::test_forward_range;
+using __gnu_test::test_range;
+using __gnu_test::test_sized_range_sized_sent;
+using __gnu_test::input_iterator_wrapper_nocopy;
namespace ranges = std::ranges;
@@ -160,6 +163,28 @@ test02()
}
}
+void
+test03()
+{
+ // LWG 3355
+ {
+ int x[3] = {0};
+ int y[3];
+ test_sized_range_sized_sent<int, input_iterator_wrapper_nocopy> rx(x);
+ ranges::uninitialized_move(rx, y);
+ ranges::uninitialized_move_n(rx.begin(), 3, y, y+3);
+ }
+
+ {
+ int x[3] = {0};
+ int y[3];
+ test_range<int, input_iterator_wrapper_nocopy> rx(x);
+ test_forward_range<int> ry(y);
+ ranges::uninitialized_move(rx, y);
+ ranges::uninitialized_move_n(rx.begin(), 3, ry.begin(), ry.end());
+ }
+}
+
int
main()
{
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