156ab87500
See: * https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc/77319 * https://discourse.llvm.org/t/rfc-project-hand-in-hand-llvm-libc-libc-code-sharing/77701 We're dropping support for C++03 for Zig due to the first change; it would be insane to ship 1018 duplicate header files just for this outdated use case. As a result of the second change, I had to bring in a subset of the headers from llvm-libc since libc++ now depends on these. Hopefully we can continue to get away with not copying the entirety of llvm-libc.
104 lines
3.8 KiB
C++
Vendored
104 lines
3.8 KiB
C++
Vendored
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___PSTL_CPU_ALGOS_ANY_OF_H
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#define _LIBCPP___PSTL_CPU_ALGOS_ANY_OF_H
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#include <__algorithm/any_of.h>
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#include <__assert>
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#include <__atomic/atomic.h>
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#include <__atomic/memory_order.h>
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#include <__config>
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#include <__iterator/concepts.h>
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#include <__pstl/backend_fwd.h>
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#include <__pstl/cpu_algos/cpu_traits.h>
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#include <__type_traits/is_execution_policy.h>
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#include <__utility/move.h>
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#include <__utility/pair.h>
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#include <cstdint>
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#include <optional>
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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#if _LIBCPP_STD_VER >= 17
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_LIBCPP_BEGIN_NAMESPACE_STD
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namespace __pstl {
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template <class _Backend, class _Index, class _Brick>
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_LIBCPP_HIDE_FROM_ABI optional<bool> __parallel_or(_Index __first, _Index __last, _Brick __f) {
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std::atomic<bool> __found(false);
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auto __ret = __cpu_traits<_Backend>::__for_each(__first, __last, [__f, &__found](_Index __i, _Index __j) {
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if (!__found.load(std::memory_order_relaxed) && __f(__i, __j)) {
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__found.store(true, std::memory_order_relaxed);
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__cpu_traits<_Backend>::__cancel_execution();
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}
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});
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if (!__ret)
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return nullopt;
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return static_cast<bool>(__found);
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}
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// TODO: check whether __simd_first() can be used here
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template <class _Index, class _DifferenceType, class _Pred>
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_LIBCPP_HIDE_FROM_ABI bool __simd_or(_Index __first, _DifferenceType __n, _Pred __pred) noexcept {
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_DifferenceType __block_size = 4 < __n ? 4 : __n;
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const _Index __last = __first + __n;
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while (__last != __first) {
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int32_t __flag = 1;
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_PSTL_PRAGMA_SIMD_REDUCTION(& : __flag)
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for (_DifferenceType __i = 0; __i < __block_size; ++__i)
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if (__pred(*(__first + __i)))
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__flag = 0;
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if (!__flag)
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return true;
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__first += __block_size;
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if (__last - __first >= __block_size << 1) {
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// Double the block _Size. Any unnecessary iterations can be amortized against work done so far.
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__block_size <<= 1;
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} else {
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__block_size = __last - __first;
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}
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}
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return false;
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}
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template <class _Backend, class _RawExecutionPolicy>
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struct __cpu_parallel_any_of {
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template <class _Policy, class _ForwardIterator, class _Predicate>
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_LIBCPP_HIDE_FROM_ABI optional<bool>
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operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) const noexcept {
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if constexpr (__is_parallel_execution_policy_v<_RawExecutionPolicy> &&
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__has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
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return __pstl::__parallel_or<_Backend>(
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__first, __last, [&__policy, &__pred](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
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using _AnyOfUnseq = __pstl::__any_of<_Backend, __remove_parallel_policy_t<_RawExecutionPolicy>>;
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auto __res = _AnyOfUnseq()(std::__remove_parallel_policy(__policy), __brick_first, __brick_last, __pred);
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_LIBCPP_ASSERT_INTERNAL(__res, "unseq/seq should never try to allocate!");
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return *std::move(__res);
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});
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} else if constexpr (__is_unsequenced_execution_policy_v<_RawExecutionPolicy> &&
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__has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
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return __pstl::__simd_or(__first, __last - __first, __pred);
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} else {
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return std::any_of(__first, __last, __pred);
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}
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}
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};
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} // namespace __pstl
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_STD_VER >= 17
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___PSTL_CPU_ALGOS_ANY_OF_H
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