b68e2eba0b
``` --------------------------------------------------- Benchmark old new --------------------------------------------------- bm_mismatch<char>/1 0.835 ns 2.37 ns bm_mismatch<char>/2 1.44 ns 2.60 ns bm_mismatch<char>/3 2.06 ns 2.83 ns bm_mismatch<char>/4 2.60 ns 3.29 ns bm_mismatch<char>/5 3.15 ns 3.77 ns bm_mismatch<char>/6 3.82 ns 4.17 ns bm_mismatch<char>/7 4.29 ns 4.52 ns bm_mismatch<char>/8 4.78 ns 4.86 ns bm_mismatch<char>/16 9.06 ns 7.54 ns bm_mismatch<char>/64 31.7 ns 19.1 ns bm_mismatch<char>/512 249 ns 8.16 ns bm_mismatch<char>/4096 1956 ns 44.2 ns bm_mismatch<char>/32768 15498 ns 501 ns bm_mismatch<char>/262144 123965 ns 4479 ns bm_mismatch<char>/1048576 495668 ns 21306 ns bm_mismatch<short>/1 0.710 ns 2.12 ns bm_mismatch<short>/2 1.03 ns 2.66 ns bm_mismatch<short>/3 1.29 ns 3.56 ns bm_mismatch<short>/4 1.68 ns 4.29 ns bm_mismatch<short>/5 1.96 ns 5.18 ns bm_mismatch<short>/6 2.59 ns 5.91 ns bm_mismatch<short>/7 2.86 ns 6.63 ns bm_mismatch<short>/8 3.19 ns 7.33 ns bm_mismatch<short>/16 5.48 ns 13.0 ns bm_mismatch<short>/64 16.6 ns 4.06 ns bm_mismatch<short>/512 130 ns 13.8 ns bm_mismatch<short>/4096 985 ns 93.8 ns bm_mismatch<short>/32768 7846 ns 1002 ns bm_mismatch<short>/262144 63217 ns 10637 ns bm_mismatch<short>/1048576 251782 ns 42471 ns bm_mismatch<int>/1 0.716 ns 1.91 ns bm_mismatch<int>/2 1.21 ns 2.49 ns bm_mismatch<int>/3 1.38 ns 3.46 ns bm_mismatch<int>/4 1.71 ns 4.04 ns bm_mismatch<int>/5 2.00 ns 4.98 ns bm_mismatch<int>/6 2.43 ns 5.67 ns bm_mismatch<int>/7 3.05 ns 6.38 ns bm_mismatch<int>/8 3.22 ns 7.09 ns bm_mismatch<int>/16 5.18 ns 12.8 ns bm_mismatch<int>/64 16.6 ns 5.28 ns bm_mismatch<int>/512 129 ns 25.2 ns bm_mismatch<int>/4096 1009 ns 201 ns bm_mismatch<int>/32768 7776 ns 2144 ns bm_mismatch<int>/262144 62371 ns 20551 ns bm_mismatch<int>/1048576 254750 ns 90097 ns ```
79 lines
2.5 KiB
C++
79 lines
2.5 KiB
C++
//===----------------------------------------------------------------------===//
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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___BIT_COUNTR_H
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#define _LIBCPP___BIT_COUNTR_H
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#include <__bit/rotate.h>
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#include <__concepts/arithmetic.h>
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#include <__config>
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#include <limits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_ctz(unsigned __x) _NOEXCEPT {
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return __builtin_ctz(__x);
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}
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_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_ctz(unsigned long __x) _NOEXCEPT {
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return __builtin_ctzl(__x);
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}
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_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __libcpp_ctz(unsigned long long __x) _NOEXCEPT {
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return __builtin_ctzll(__x);
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}
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template <class _Tp>
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_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int __countr_zero(_Tp __t) _NOEXCEPT {
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if (__t == 0)
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return numeric_limits<_Tp>::digits;
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if (sizeof(_Tp) <= sizeof(unsigned int))
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return std::__libcpp_ctz(static_cast<unsigned int>(__t));
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else if (sizeof(_Tp) <= sizeof(unsigned long))
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return std::__libcpp_ctz(static_cast<unsigned long>(__t));
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else if (sizeof(_Tp) <= sizeof(unsigned long long))
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return std::__libcpp_ctz(static_cast<unsigned long long>(__t));
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else {
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int __ret = 0;
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const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits;
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while (static_cast<unsigned long long>(__t) == 0uLL) {
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__ret += __ulldigits;
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__t >>= __ulldigits;
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}
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return __ret + std::__libcpp_ctz(static_cast<unsigned long long>(__t));
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}
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}
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#if _LIBCPP_STD_VER >= 20
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template <__libcpp_unsigned_integer _Tp>
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_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr int countr_zero(_Tp __t) noexcept {
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return std::__countr_zero(__t);
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}
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template <__libcpp_unsigned_integer _Tp>
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_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr int countr_one(_Tp __t) noexcept {
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return __t != numeric_limits<_Tp>::max() ? std::countr_zero(static_cast<_Tp>(~__t)) : numeric_limits<_Tp>::digits;
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}
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#endif // _LIBCPP_STD_VER >= 20
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___BIT_COUNTR_H
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