Instead of using `reverse_iterator`, share the optimization between the 4 algorithms. The key observation here that `memmove` applies to both `copy` and `move` identically, and to their `_backward` versions very similarly. All algorithms now follow the same pattern along the lines of:
```
if constexpr (can_memmove<InIter, OutIter>) {
memmove(first, last, out);
} else {
naive_implementation(first, last, out);
}
```
A follow-up will delete `unconstrained_reverse_iterator`.
This patch removes duplication and divergence between `std::copy`, `std::move` and `std::move_backward`. It also improves testing:
- the test for whether the optimization is used only applied to `std::copy` and, more importantly, was essentially a no-op because it would still pass if the optimization was not used;
- there were no tests to make sure the optimization is not used when the effect would be visible.
Differential Revision: https://reviews.llvm.org/D130695
This was discussed on Discord with the consensus that we should rename the macros.
Reviewed By: ldionne, Mordante, var-const, avogelsgesang, jloser, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D131498
When we ship LLVM 16, <ranges> won't be considered experimental anymore.
We might as well do this sooner rather than later.
Differential Revision: https://reviews.llvm.org/D132151
Also fix `ranges::stable_sort` and `ranges::inplace_merge` to support
proxy iterators now that their internal implementations can correctly
dispatch `rotate`.
Differential Revision: https://reviews.llvm.org/D130758
This adds a C++20-version of `reverse_iterator` which doesn't SFINAE away the operators for use inside the classic STL algorithms. Pre-C++20 `_AlgRevIter` is just an alias for `reverse_iterator`.
Reviewed By: var-const, #libc
Spies: huixie90, libcxx-commits
Differential Revision: https://reviews.llvm.org/D128864
Simplify the implementation of `std::copy` and `std::move` by using `__unwrap_iter` and `__rewrap_iter` to unwrap and rewrap `reverse_iterator<reverse_iterator<Iter>>` instead of specializing `__copy_impl` and `__move_impl`.
Reviewed By: ldionne, #libc
Spies: wenlei, libcxx-commits
Differential Revision: https://reviews.llvm.org/D127049
Changes in [P0896](https://wg21.link/p0896):
- add `disable_sized_sentinel_for`;
- add `iter_move` and `iter_swap`;
- add a `requires` clause to the `operator->`;
- add `iterator_concept`;
- check that the `Iterator` template parameter is a bidirectional
iterator;
- add constraints to all comparison operators;
- change the definitions of `iterator_category`, `value_type`,
`difference_type` and `reference` (changes to `iterator_category` were
already implemented).
Also add a few forgotten things to the `reverse_iterator` synopsis
(notably the spaceship operator).
Differential Revision: https://reviews.llvm.org/D120180
All supported compilers that support C++20 now support concepts. So, remove
`_LIB_LIBCPP_HAS_NO_CONCEPTS` in favor of `_LIBCPP_STD_VER > 17`. Similarly in
the tests, remove `// UNSUPPORTED: libcpp-no-concepts`.
Differential Revision: https://reviews.llvm.org/D121528
This commit reverts 5aaefa51 (and also partly 7f285f48e7 and b6d75682f9,
which were related to the original commit). As landed, 5aaefa51 had
unintended consequences on some downstream bots and didn't have proper
coverage upstream due to a few subtle things. Implementing this is
something we should do in libc++, however we'll first need to address
a few issues listed in https://reviews.llvm.org/D106124#3349710.
Differential Revision: https://reviews.llvm.org/D120683
libc++ has started splicing standard library headers into much more
fine-grained content for maintainability. It's very likely that outdated
and naive tooling (some of which is outside of LLVM's scope) will
suggest users include things such as <__ranges/access.h> instead of
<ranges>, and Hyrum's law suggests that users will eventually begin to
rely on this without the help of tooling. As such, this commit
intends to protect users from themselves, by making it a hard error for
anyone outside of the standard library to include libc++ detail headers.
Differential Revision: https://reviews.llvm.org/D106124
Per Discord discussion, we're normalizing on a simple `!defined(_LIBCPP_HAS_NO_CONCEPTS)`
so that we can do a big search-and-replace for `!defined(_LIBCPP_HAS_NO_CONCEPTS)`
back into `_LIBCPP_STD_VER > 17` when we're ready to abandon support for concept-syntax-less
compilers.
Differential Revision: https://reviews.llvm.org/D118748
This essentially reverts e02ed1c255 and puts in a new fix, which makes `path::iterator`
a true C++20 `bidirectional_iterator`, but downgrades it to an `input_iterator` in C++17.
Fixes#37852.
Differential Revision: https://reviews.llvm.org/D116489
The NFC part of D116809. We still want to enforce this in CI,
but the mechanism for that is still to-be-determined.
Differential Revision: https://reviews.llvm.org/D116809
This patch implements operator<=> for std::reverse_iterator and
also adds a test that checks that three-way comparison of different
instantiations of std::reverse_iterator works as expected (related to
D113417).
Reviewed By: ldionne, Quuxplusone, #libc
Differential Revision: https://reviews.llvm.org/D113695
The template std::is_assignable<T, U> checks that T is assignable from
U. Hence, the order of operands in the instantiation of
std::is_assignable in the std::reverse_iterator::operator= condition
should be reversed.
This issue remained unnoticed because std::reverse_iterator has an
implicit conversion constructor. This patch adds a test to check that
the assignment operator is used directly, without any implicit
conversions. The patch also adds a similar test for
std::move_iterator.
Reviewed By: Quuxplusone, ldionne, #libc
Differential Revision: https://reviews.llvm.org/D113417
In other places in the code, we use lowercase spelling for things that
are not available in prior standards.
Differential Revision: https://reviews.llvm.org/D109435
Vitaly Buka