libstdc++-v3/testsuite/25_algorithms/pstl/alg_nonmodifying/find.cc

// -*- C++ -*-
// { dg-options "-ltbb" }
// { dg-do run { target c++17 } }
// { dg-timeout-factor 3 }
// { dg-require-effective-target tbb_backend }

//===-- find.pass.cpp -----------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// Tests for find
#include "pstl/pstl_test_config.h"

#ifdef PSTL_STANDALONE_TESTS
#include "pstl/execution"
#include "pstl/algorithm"
#else
#include <execution>
#include <algorithm>
#endif // PSTL_STANDALONE_TESTS

#include "pstl/test_utils.h"

using namespace TestUtils;

struct test_find
{
#if _PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN ||                                                            \
    _PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN //dummy specialization by policy type, in case of broken configuration
    template <typename Iterator, typename Value>
    void
    operator()(pstl::execution::unsequenced_policy, Iterator first, Iterator last, Value value)
    {
    }
    template <typename Iterator, typename Value>
    void
    operator()(pstl::execution::parallel_unsequenced_policy, Iterator first, Iterator last, Value value)
    {
    }
#endif

    template <typename Policy, typename Iterator, typename Value>
    void
    operator()(Policy&& exec, Iterator first, Iterator last, Value value)
    {
        auto i = std::find(first, last, value);
        auto j = find(exec, first, last, value);
        EXPECT_TRUE(i == j, "wrong return value from find");
    }
};

template <typename T, typename Value, typename Hit, typename Miss>
void
test(Value value, Hit hit, Miss miss)
{
    // Try sequences of various lengths.
    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
    {
        Sequence<T> in(n, [&](size_t k) -> T { return miss(n ^ k); });
        // Try different find positions, including not found.
        // By going backwards, we can add extra matches that are *not* supposed to be found.
        // The decreasing exponential gives us O(n) total work for the loop since each find takes O(m) time.
        for (size_t m = n; m > 0; m *= 0.6)
        {
            if (m < n)
                in[m] = hit(n ^ m);
            invoke_on_all_policies(test_find(), in.begin(), in.end(), value);
            invoke_on_all_policies(test_find(), in.cbegin(), in.cend(), value);
        }
    }
}

// Type defined for sake of checking that std::find works with asymmetric ==.
class Weird
{
    Number value;

  public:
    friend bool
    operator==(Number x, Weird y)
    {
        return x == y.value;
    }
    Weird(int32_t val, OddTag) : value(val, OddTag()) {}
};

int32_t
main()
{
    // Note that the "hit" and "miss" functions here avoid overflow issues.
    test<Number>(Weird(42, OddTag()), [](int32_t j) { return Number(42, OddTag()); }, // hit
                 [](int32_t j) { return Number(j == 42 ? 0 : j, OddTag()); });        // miss

    // Test with value that is equal to two different bit patterns (-0.0 and 0.0)
    test<float32_t>(-0.0, [](int32_t j) { return j & 1 ? 0.0 : -0.0; }, // hit
                    [](int32_t j) { return j == 0 ? ~j : j; });         // miss

    std::cout << done() << std::endl;
    return 0;
}