We are introducing branchless variants for sort3, sort4 and sort5.
These sorting functions have been generated using Reinforcement
Learning and aim to replace __sort3, __sort4 and __sort5 variants
for integral types.
The libc++ benchmarks were run on isolated machines for Skylake, ARM and
AMD architectures and achieve statistically significant improvement in
sorting random integers on test cases from sort1 to sort262144 for
uint32 and uint64.
A full performance overview for Intel Skylake, AMD and Arm can be
found here: https://bit.ly/3AtesYf
Reviewed By: ldionne, #libc, philnik
Spies: daniel.mankowitz, mgrang, Quuxplusone, andreamichi, philnik, libcxx-commits, nilayvaish, kristof.beyls
Differential Revision: https://reviews.llvm.org/D118029
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
As a fly-by fix, enable the complexity-changing assertions in __debug_less
only when the full debug mode is enabled, since debugging level 0 is usually
understood to only contain basic assertions that do not change the complexity
of algorithms.
Differential Revision: https://reviews.llvm.org/D121129
This commit reverts 5aaefa51 (and also partly 7f285f48e77 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 It's very likely that outdated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
This is the first step towards disentangling the debug mode and assertions
in libc++. This patch doesn't make any functional change: it simply moves
_LIBCPP_ASSERT-related stuff to its own file so as to make it clear that
libc++ assertions and the debug mode are different things. Future patches
will make it possible to enable assertions without enabling the debug
mode.
Differential Revision: https://reviews.llvm.org/D119769
The logic here is that we are disabling *only* things in `std::ranges::`.
Everything in `std::` is permitted, including `default_sentinel`, `contiguous_iterator`,
`common_iterator`, `projected`, `swappable`, and so on. Then, we include
anything from `std::ranges::` that is required in order to make those things
work: `ranges::swap`, `ranges::swap_ranges`, `input_range`, `ranges::begin`,
`ranges::iter_move`, and so on. But then that's all. Everything else (including
notably all of the "views" and the `std::views` namespace itself) is still
locked up behind `_LIBCPP_HAS_NO_INCOMPLETE_RANGES`.
Differential Revision: https://reviews.llvm.org/D118736
`ranges_swap_ranges.h` includes `<type_traits>` but does not use anything from
it. So, remove the include.
Differential Revision: https://reviews.llvm.org/D119491
In libc++, checking specific `_LIBCPP_DEBUG_LEVEL` levels is used everywhere except in `comp_ref_type.h`. `_LIBCPP_DEBUG` is meant as a user-facing option, and internally libc++ should be checking the value of `_LIBCPP_DEBUG_LEVEL`.
The definition of `std::__debug_less` doesn't need to be hidden behind the macro, we can unconditionally expose it. It will be unused by `__comp_ref_type` unless debug mode is enabled.
This was suggested in D118940.
Reviewed By: #libc, philnik, Quuxplusone, ldionne
Differential Revision: https://reviews.llvm.org/D118950
b07b5bd72716625e0976a84d23652d94d8d0165a adds a use of `__comp_ref_type.h` to `std::min`. When libc++ is built with `-D_LIBCPP_DEBUG=0`, this enables `std::__debug_less`, which is only marked constexpr after c++17.
`std::min` itself is marked as being `constexpr` as of c++14, so by extension, `std::__debug_less` should also be marked `constexpr` for the same versions so that `std::min` can use it. This change lowers the guard from `> 17` to `> 11`.
Reproducer in godbolt: https://godbolt.org/z/ans3TGsj8
```
constexpr int x() { return std::min<int>({1, 2, 3, 4}); }
static_assert(x() == 1);
```
Reviewed By: #libc, philnik, Quuxplusone, ldionne
Differential Revision: https://reviews.llvm.org/D118940
Basically a rebase of D104980; most of that patch had already happened
via gradual drive-by changes, but this finishes it up.
Don't touch the inclusions from `<__functional_base>`, `<__hash_table>`,
or `<__locale>`; those could be removed if we propagated the
inclusions up to the includers of those files, but there are lots
of those includers.
`<algorithm>`, `<functional>`, and `<memory>` already include `<utility>`
at the top level. `<iterator>` did not, so I've added it there.
Differential Revision: https://reviews.llvm.org/D119020
The macro that opts out of `std::ranges::` functionality is called
`_LIBCPP_HAS_NO_INCOMPLETE_RANGES`, and is unrelated to this macro
which is specifically about _compiler_ support for the _syntax_.
The only non-mechanical diff here is in `<__config>`.
Differential Revision: https://reviews.llvm.org/D118507
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
If `__first == __middle`, then `partial_sort` is a no-op; don't
bother to iterate all the way from `__middle` to `__end`.
Fixes#49431.
Differential Revision: https://reviews.llvm.org/D116296
This is not mandated by the standard, so it goes in libcxx/test/libcxx/.
It's certainly arguable that the algorithms changed here
(`is_heap`, `is_sorted`, `min`, `max`) are harmless and we should
just let them copy their comparators once. But at the same time,
it's nice to have all our algorithms be 100% consistent and never
copy a comparator, not even once.
Differential Revision: https://reviews.llvm.org/D114136
This effort is dedicated to deflake the tests of the users which depend
on the unspecified behavior of algorithms and containers. This also
might help updating the sorting algorithm in libcxx which has the
quadratic worst case in the future or at least create a new one under
flag.
For detailed design, please see the design doc I provide in the patch.
Differential Revision: https://reviews.llvm.org/D96946
Some embedded platforms do not wish to support the C library functionality
for handling wchar_t because they have no use for it. It makes sense for
libc++ to work properly on those platforms, so this commit adds a carve-out
of functionality for wchar_t.
Unfortunately, unlike some other carve-outs (e.g. random device), this
patch touches several parts of the library. However, despite the wide
impact of this patch, I still think it is important to support this
configuration since it makes it much simpler to port libc++ to some
embedded platforms.
Differential Revision: https://reviews.llvm.org/D111265
Detected by evil-izing the widely used `MoveOnly` testing type.
I had to patch some tests that were themselves using its comma operator,
but I think that's a worthwhile cost in order to catch more places
in our headers that needed comma-proofing.
The trick here is that even `++ptr, SomeClass()` can find a comma operator
by ADL, if `ptr` is of type `Evil*`. (A comma between two operands
of non-class-or-enum type is always treated as the built-in
comma, without ADL. But if either operand is class-or-enum, then
ADL happens for _both_ operands' types.)
Differential Revision: https://reviews.llvm.org/D109414
