207b919735
Patch by Denis Yaroshevskiy (denis.yaroshevskij@gmail.com) The rational and measurements can be found in the bug description: https://bugs.llvm.org/show_bug.cgi?id=39129 Reviewed as https://reviews.llvm.org/D52697 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@345525 91177308-0d34-0410-b5e6-96231b3b80d8
60 lines
1.6 KiB
C++
60 lines
1.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// <algorithm>
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// template <typename _Tp> _Tp __half_positive(const _Tp&);
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// __half_positive divide integer number by 2 as unsigned number
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// if it's safe to do so. It can be an important optimization for lower bound,
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// for example.
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#include <algorithm>
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#include <cassert>
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#include <limits>
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#include <type_traits>
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#include "test_macros.h"
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#include "user_defined_integral.hpp"
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namespace {
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template <class IntType, class UnderlyingType = IntType>
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TEST_CONSTEXPR bool test(IntType max_v = IntType(std::numeric_limits<UnderlyingType>::max())) {
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return std::__half_positive(max_v) == max_v / 2;
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}
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} // namespace
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int main()
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{
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{
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assert(test<char>());
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assert(test<int>());
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assert(test<long>());
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assert((test<UserDefinedIntegral<int>, int>()));
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assert(test<size_t>());
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#if !defined(_LIBCPP_HAS_NO_INT128)
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assert(test<__int128_t>());
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#endif // !defined(_LIBCPP_HAS_NO_INT128)
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}
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#if TEST_STD_VER >= 11
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{
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static_assert(test<char>(), "");
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static_assert(test<int>(), "");
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static_assert(test<long>(), "");
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static_assert(test<size_t>(), "");
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#if !defined(_LIBCPP_HAS_NO_INT128)
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static_assert(test<__int128_t>(), "");
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#endif // !defined(_LIBCPP_HAS_NO_INT128)
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}
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#endif // TEST_STD_VER >= 11
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}
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