[libc++] Optimize std::find for segmented iterators (#67224)

```
--------------------------------------------------------------------------
Benchmark o

[libc++] Optimize std::find for segmented iterators (#67224)

```
--------------------------------------------------------------------------
Benchmark old new
--------------------------------------------------------------------------
bm_find<std::deque<char>>/1 6.06 ns 10.6 ns
bm_find<std::deque<char>>/2 15.5 ns 10.6 ns
bm_find<std::deque<char>>/3 19.0 ns 10.6 ns
bm_find<std::deque<char>>/4 20.8 ns 10.6 ns
bm_find<std::deque<char>>/5 22.0 ns 10.6 ns
bm_find<std::deque<char>>/6 23.0 ns 10.5 ns
bm_find<std::deque<char>>/7 24.8 ns 10.7 ns
bm_find<std::deque<char>>/8 25.7 ns 10.6 ns
bm_find<std::deque<char>>/16 28.3 ns 10.6 ns
bm_find<std::deque<char>>/64 44.2 ns 27.0 ns
bm_find<std::deque<char>>/512 133 ns 37.6 ns
bm_find<std::deque<char>>/4096 867 ns 53.1 ns
bm_find<std::deque<char>>/32768 6838 ns 160 ns
bm_find<std::deque<char>>/262144 52897 ns 1495 ns
bm_find<std::deque<char>>/1048576 215621 ns 6077 ns
bm_find<std::deque<short>>/1 6.03 ns 6.28 ns
bm_find<std::deque<short>>/2 15.8 ns 15.8 ns
bm_find<std::deque<short>>/3 20.5 ns 20.3 ns
bm_find<std::deque<short>>/4 21.0 ns 21.0 ns
bm_find<std::deque<short>>/5 23.0 ns 22.1 ns
bm_find<std::deque<short>>/6 22.6 ns 23.0 ns
bm_find<std::deque<short>>/7 23.4 ns 23.7 ns
bm_find<std::deque<short>>/8 24.4 ns 24.9 ns
bm_find<std::deque<short>>/16 26.6 ns 27.2 ns
bm_find<std::deque<short>>/64 43.2 ns 40.9 ns
bm_find<std::deque<short>>/512 124 ns 90.7 ns
bm_find<std::deque<short>>/4096 845 ns 525 ns
bm_find<std::deque<short>>/32768 7273 ns 3194 ns
bm_find<std::deque<short>>/262144 53710 ns 24385 ns
bm_find<std::deque<short>>/1048576 216086 ns 96195 ns
bm_find<std::deque<int>>/1 6.03 ns 10.3 ns
bm_find<std::deque<int>>/2 15.6 ns 10.3 ns
bm_find<std::deque<int>>/3 19.1 ns 10.3 ns
bm_find<std::deque<int>>/4 22.3 ns 10.3 ns
bm_find<std::deque<int>>/5 23.5 ns 10.4 ns
bm_find<std::deque<int>>/6 23.1 ns 10.3 ns
bm_find<std::deque<int>>/7 23.7 ns 10.2 ns
bm_find<std::deque<int>>/8 24.5 ns 10.2 ns
bm_find<std::deque<int>>/16 27.9 ns 26.6 ns
bm_find<std::deque<int>>/64 42.6 ns 32.2 ns
bm_find<std::deque<int>>/512 123 ns 43.0 ns
bm_find<std::deque<int>>/4096 874 ns 93.5 ns
bm_find<std::deque<int>>/32768 7031 ns 751 ns
bm_find<std::deque<int>>/262144 57723 ns 6169 ns
bm_find<std::deque<int>>/1048576 230867 ns 35851 ns
bm_ranges_find<std::deque<char>>/1 5.97 ns 10.6 ns
bm_ranges_find<std::deque<char>>/2 16.0 ns 10.5 ns
bm_ranges_find<std::deque<char>>/3 19.5 ns 10.5 ns
bm_ranges_find<std::deque<char>>/4 21.1 ns 10.6 ns
bm_ranges_find<std::deque<char>>/5 22.8 ns 10.5 ns
bm_ranges_find<std::deque<char>>/6 22.8 ns 10.6 ns
bm_ranges_find<std::deque<char>>/7 23.4 ns 10.8 ns
bm_ranges_find<std::deque<char>>/8 24.1 ns 10.5 ns
bm_ranges_find<std::deque<char>>/16 26.9 ns 10.6 ns
bm_ranges_find<std::deque<char>>/64 50.2 ns 27.2 ns
bm_ranges_find<std::deque<char>>/512 126 ns 38.3 ns
bm_ranges_find<std::deque<char>>/4096 868 ns 53.8 ns
bm_ranges_find<std::deque<char>>/32768 6695 ns 161 ns
bm_ranges_find<std::deque<char>>/262144 54411 ns 1497 ns
bm_ranges_find<std::deque<char>>/1048576 241699 ns 6042 ns
bm_ranges_find<std::deque<short>>/1 6.39 ns 6.31 ns
bm_ranges_find<std::deque<short>>/2 15.8 ns 15.9 ns
bm_ranges_find<std::deque<short>>/3 19.0 ns 19.8 ns
bm_ranges_find<std::deque<short>>/4 20.8 ns 20.9 ns
bm_ranges_find<std::deque<short>>/5 21.8 ns 22.1 ns
bm_ranges_find<std::deque<short>>/6 23.0 ns 23.0 ns
bm_ranges_find<std::deque<short>>/7 23.2 ns 23.9 ns
bm_ranges_find<std::deque<short>>/8 23.7 ns 24.4 ns
bm_ranges_find<std::deque<short>>/16 26.6 ns 26.8 ns
bm_ranges_find<std::deque<short>>/64 43.4 ns 39.7 ns
bm_ranges_find<std::deque<short>>/512 131 ns 90.5 ns
bm_ranges_find<std::deque<short>>/4096 851 ns 523 ns
bm_ranges_find<std::deque<short>>/32768 7370 ns 3166 ns
bm_ranges_find<std::deque<short>>/262144 60778 ns 24814 ns
bm_ranges_find<std::deque<short>>/1048576 229288 ns 99273 ns
bm_ranges_find<std::deque<int>>/1 6.43 ns 10.2 ns
bm_ranges_find<std::deque<int>>/2 16.6 ns 10.2 ns
bm_ranges_find<std::deque<int>>/3 19.6 ns 10.2 ns
bm_ranges_find<std::deque<int>>/4 21.0 ns 10.2 ns
bm_ranges_find<std::deque<int>>/5 21.9 ns 10.4 ns
bm_ranges_find<std::deque<int>>/6 22.7 ns 10.2 ns
bm_ranges_find<std::deque<int>>/7 23.9 ns 10.2 ns
bm_ranges_find<std::deque<int>>/8 23.8 ns 10.2 ns
bm_ranges_find<std::deque<int>>/16 27.2 ns 27.1 ns
bm_ranges_find<std::deque<int>>/64 42.4 ns 32.4 ns
bm_ranges_find<std::deque<int>>/512 122 ns 43.0 ns
bm_ranges_find<std::deque<int>>/4096 895 ns 93.7 ns
bm_ranges_find<std::deque<int>>/32768 6890 ns 756 ns
bm_ranges_find<std::deque<int>>/262144 54025 ns 6102 ns
bm_ranges_find<std::deque<int>>/1048576 221558 ns 32783 ns
```

show more ...

[libc++][test] Enhance ADDITIONAL_COMPILE_FLAGS, use TEST_MEOW_DIAGNOSTIC_IGNORED sparingly (#75317)

This is the last PR that's needed (for now) to get libc++'s tests
working with MSVC's STL.

Th

[libc++][test] Enhance ADDITIONAL_COMPILE_FLAGS, use TEST_MEOW_DIAGNOSTIC_IGNORED sparingly (#75317)

This is the last PR that's needed (for now) to get libc++'s tests
working with MSVC's STL.

The ADDITIONAL_COMPILE_FLAGS machinery is very useful, but also very
problematic for MSVC, as it doesn't understand most of Clang's compiler
options. We've been dealing with this by simply marking anything that
uses ADDITIONAL_COMPILE_FLAGS as FAIL or SKIPPED, but that creates
significant gaps in test coverage.

Fortunately, ADDITIONAL_COMPILE_FLAGS also supports "features", which
can be slightly enhanced to send Clang-compatible and MSVC-compatible
options to the right compilers.

This patch adds the gcc-style-warnings and cl-style-warnings Lit features,
and uses that to pass the appropriate warning flags to tests. It also uses
TEST_MEOW_DIAGNOSTIC_IGNORED for a few local suppressions of MSVC
warnings.

show more ...

[libc++] Make sure ranges algorithms and views handle boolean-testable correctly (#69378)

Before this patch, we would fail to implicitly convert the result of
predicates to bool, which means we'd p

[libc++] Make sure ranges algorithms and views handle boolean-testable correctly (#69378)

Before this patch, we would fail to implicitly convert the result of
predicates to bool, which means we'd potentially perform a copy or move
construction of the boolean-testable, which isn't allowed. The same
holds true for comparing iterators against sentinels, which is allowed
to return a boolean-testable type.

We already had tests aiming to ensure correct handling of these types,
but they failed to provide appropriate coverage in several cases due to
guaranteed RVO. This patch fixes the tests, adds tests for missing
algorithms and views, and fixes the actual problems in the code.

Fixes #69074

show more ...

[libc++] Forward to std::{,w}memchr in std::find

Reviewed By: #libc, ldionne

Spies: Mordante, libcxx-commits, ldionne, mikhail.ramalho

Differential Revision: https://reviews.llvm.org/D144394

[libc++] Remove tests from ranges.pass.cpp which violate semantic requirements

This also removes some tests which we have grouped together into robust_from_*.pass.cpp tests.

Specifically, checking

[libc++] Remove tests from ranges.pass.cpp which violate semantic requirements

This also removes some tests which we have grouped together into robust_from_*.pass.cpp tests.

Specifically, checking that
- `ranges::dangling` is returned is done in `libcxx/test/std/algorithms/ranges_robust_against_dangling.pass.cpp`
- `std::invoke` is used is done in `libcxx/test/std/algorithms/ranges_robust_against_omitting_invoke.pass.cpp`.
- implicit conversion to bool works is done in `libcxx/test/std/algorithms/ranges_robust_against_nonbool_predicates.pass.cpp`

Checking the comparison order is invalid because the `operator==` isn't symmetric.
Checking what the exact type of `operator==` is, is invalid because comparing the same object has to yield the same results if the objects are not modified.

Reviewed By: ldionne, #libc

Spies: EricWF, libcxx-commits

Differential Revision: https://reviews.llvm.org/D150588

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] Add implicit conversion to bool test for ranges::find{, if, if_not}

Reviewed By: ldionne, var-const, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D1

[libc++][ranges] Add implicit conversion to bool test for ranges::find{, if, if_not}

Reviewed By: ldionne, var-const, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D122011

show more ...

[libc++][ranges] Implement ranges::find{, _if, _if_not}

Reviewed By: var-const, #libc, ldionne

Spies: ldionne, tcanens, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D1212

[libc++][ranges] Implement ranges::find{, _if, _if_not}

Reviewed By: var-const, #libc, ldionne

Spies: ldionne, tcanens, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D121248

show more ...