[libc++] P2770R0: Stashing stashing iterators for proper flattening (#66033)

- Partially implements P2770R0 (http://wg21.link/p2770)
- Fixes https://wg21.link/LWG3698, https://wg21.link/LWG3700, an

[libc++] P2770R0: Stashing stashing iterators for proper flattening (#66033)

- Partially implements P2770R0 (http://wg21.link/p2770)
- Fixes https://wg21.link/LWG3698, https://wg21.link/LWG3700, and https://wg21.link/LWG3791
- join_with_view hasn't been done yet since this type isn't implemented yet
- Rename tuple test directory to match the standard (which changed in P2770R0)
- Rename join_view test directory to match the standard

show more ...

[libcxx][test] std::array::iterator are not pointers by C++ standard (#70729)

This is to modify a list of libcxx tests written under the assumption
that iterators for std::array, std::string_view,

[libcxx][test] std::array::iterator are not pointers by C++ standard (#70729)

This is to modify a list of libcxx tests written under the assumption
that iterators for std::array, std::string_view, and std::string are
pointers. The motivation for this PR is to make the tests more universal
and potentially being used to test other C++ standard library
implementations, for example
[microsoft/STL](https://github.com/microsoft/STL).

I can confirm that this patch makes a number of tests compatible with
microsoft STL:
`Failed : 204 (2.12%)` -> `Failed : 136 (1.42%)`
, and does not break any tests on `libcxx`.

This is not a complete list of such incompatibilities, but I am hoping
this will start a discussion about whether we are open to accepting such
changes.

show more ...

[libc++] Mark slow tests as unsupported on GCC

Some tests in our test suite are unbelievably slow on GCC due to the
use of the always_inline attribute. See [1] for more details.

This patch introduc

[libc++] Mark slow tests as unsupported on GCC

Some tests in our test suite are unbelievably slow on GCC due to the
use of the always_inline attribute. See [1] for more details.

This patch introduces the GCC-ALWAYS_INLINE-FIXME lit feature to
disable tests that are plagued by that issue. At the same time, it
moves several existing tests from ad-hoc `UNSUPPORTED: gcc-12` markup
to the new GCC-ALWAYS_INLINE-FIXME feature, and marks the slowest tests
reported by the CI as `UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME`.

[1]: https://discourse.llvm.org/t/rfc-stop-supporting-extern-instantiations-with-gcc/71277/1

Differential Revision: https://reviews.llvm.org/D152736

show more ...

[libc++][ranges] Temporarily mark `ranges::join_view` as experimental.

This is in anticipation of https://isocpp.org/files/papers/D2770R0.html,
which is ABI-breaking for `join_view`.

Differential R

[libc++][ranges] Temporarily mark `ranges::join_view` as experimental.

This is in anticipation of https://isocpp.org/files/papers/D2770R0.html,
which is ABI-breaking for `join_view`.

Differential Revision: https://reviews.llvm.org/D142520

show more ...

[libc++] Enable segmented iterator optimizations for join_view::iterator

Reviewed By: ldionne, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D138413

[libc++] Refactor deque::iterator algorithm optimizations

This has multiple benefits:
- The optimizations are also performed for the `ranges::` versions of the algorithms
- Code duplication is reduc

[libc++] Refactor deque::iterator algorithm optimizations

This has multiple benefits:
- The optimizations are also performed for the `ranges::` versions of the algorithms
- Code duplication is reduced
- it is simpler to add this optimization for other segmented iterators,
like `ranges::join_view::iterator`
- Algorithm code is removed from `<deque>`

Reviewed By: ldionne, huixie90, #libc

Spies: mstorsjo, sstefan1, EricWF, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D132505

show more ...

Reapply "[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`"

This reverts commit a6e1080b87db8fbe0e1afadd96af5a3c0bd5e279.

Fix the conditions when the `memmove` optimization can be

Reapply "[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`"

This reverts commit a6e1080b87db8fbe0e1afadd96af5a3c0bd5e279.

Fix the conditions when the `memmove` optimization can be applied and refactor them out into a reusable type trait, fix and significantly expand the tests.

Differential Revision: https://reviews.llvm.org/D139235

show more ...

Revert "[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`"

Breaks msan, asan

https://lab.llvm.org/buildbot/#/builders/5/builds/27904

This reverts commit 005916de58f73aa5c4264c084b

Revert "[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`"

Breaks msan, asan

https://lab.llvm.org/buildbot/#/builders/5/builds/27904

This reverts commit 005916de58f73aa5c4264c084ba7b0e21040d88f.

show more ...

[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`

Instead of using `reverse_iterator`, share the optimization between the 4 algorithms. The key observation here that `memmove` appli

[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`

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

show more ...

[libc++] Make <ranges> non-experimental

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://re

[libc++] Make <ranges> non-experimental

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

show more ...

[libc++][ranges] Fix the return value of `{copy,move}_backward`.

The return value for both of these algorithms is specified as
```
`{last, result - N}` for the overloads in namespace `ranges`.
```
B

[libc++][ranges] Fix the return value of `{copy,move}_backward`.

The return value for both of these algorithms is specified as
```
`{last, result - N}` for the overloads in namespace `ranges`.
```
But the current implementation instead returns `{first, result - N}`.

Also add both algorithms to the relevant "robust" tests.

Differential Revision: https://reviews.llvm.org/D130968

show more ...

[libc++] Fix algorithms which use reverse_iterator

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 `_AlgR

[libc++] Fix algorithms which use reverse_iterator

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

show more ...

[libcxx][ranges] Create a test tool `ProxyIterator` that customises `iter_move` and `iter_swap`

It is meant to be used in ranges algorithm tests.
It is much simplified version of C++23's tuple + zip

[libcxx][ranges] Create a test tool `ProxyIterator` that customises `iter_move` and `iter_swap`

It is meant to be used in ranges algorithm tests.
It is much simplified version of C++23's tuple + zip_view.
Using std::swap would cause compilation failure and using `std::move` would not create the correct rvalue proxy which would result in copies.

Differential Revision: https://reviews.llvm.org/D129099

show more ...

[libc++] Implement ranges::copy{, _n, _if, _backward}

Reviewed By: Mordante, var-const, #libc

Spies: sstefan1, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D122982