从捕获的值变量分配给 Lambda 参数时出现 gcc 编译器分段错误

Question

我正在研究 this answer 并编写了代码：

bool generate(vector<int>& temp, int& target, const size_t width, const size_t i) {
    const auto replacement = temp[i];
    const auto result = target > replacement;

    if (result) {
        for_each(begin(temp), next(begin(temp), min(temp.size(), i + width - 1)), [=](auto& it) {
            if (target == it) {
                it = replacement;
            } else if (target < it) {
                --it;
            } });
    }
    target = replacement;
    return result;
}

int main() {
    const vector<char> rooms = { 0b1101,    0b110,  0b1101, 0b110,  0b1100, 0b101,  0b110,
                                 0b1110,    0b1001, 0b110,  0b1011, 0b1010, 0b1111, 0b1010,
                                 0b1000,    0b101,  0b11,   0b1110, 0b1011, 0b1110, 0b1010,
                                 0b1011,    0b1101, 0b101,  0b1,    0b101,  0b11,   0b1011 };
    const size_t width = 7U;
    auto result = 0;
    vector<int> temp(rooms.size());

    for (size_t i = 0U; i < rooms.size(); ++i) {
        const auto toWest = (rooms[i] & 0b1000) == 0;
        const auto toNorth = (rooms[i] & 0b100) == 0;
        const auto toEast = (rooms[i] & 0b10) == 0;
        const auto toSouth = (rooms[i] & 0b1) == 0;
        const auto west = toWest && temp[i - 1] != 0 ? temp[i - 1] : numeric_limits<int>::max();
        const auto north = toNorth && temp[i - width] != 0 ? temp[i - width] : numeric_limits<int>::max();
        const auto east = toEast && temp[i + 1] != 0 ? temp[i + 1] : numeric_limits<int>::max();

        temp[i] = min({ temp[i] != 0 ? temp[i] : numeric_limits<int>::max(), result + 1, west, north, east });

        if (temp[i] == result + 1) ++result;

        if (toWest) result -= generate(temp, temp[i - 1], width, i);
        if (toNorth) result -= generate(temp, temp[i - width], width, i);
        if (toEast) result -= generate(temp, temp[i + 1], width, i);
        if (toSouth) temp[i + width] = temp[i];
    }

    for (auto it = cbegin(temp); it != cend(temp);) {
        for (auto i = 0; i < width; ++i, ++it) cout << *it << '\t';
        cout << endl;
    }

    cout << endl << result << endl;
}

When compiled on gcc这段代码给出了错误：

Internal compiler error: Segmentation fault it = replacement;

我已经在 gcc 5.1、5.2 和 5.3 上本地尝试过，它在所有这些上都给出了相同的编译器错误。 Clang seems happy with the code 以及 Visual Studio。这只是一个编译器错误，不是我犯的错误，对吧？

Answer 1

在 lambda 中按值捕获常量变量以及随后由于分段错误导致的内部编译器错误是 gcc 5.1 - 5.3 中的错误： https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70691

如果您需要修复此错误的云编译器，您可以在 http://coliru.stacked-crooked.com because it's using gcc 6.1 which has resolved the issue

上使用 gcc

gcc 5.4 也应该更正这个：https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70691#c5
它于 16 年 6 月 3 日发布：https://gcc.gnu.org/gcc-5/

从捕获的值变量分配给 Lambda 参数时出现 gcc 编译器分段错误

gcc Compiler Segmentation Fault When Assigning from Value Captured Variable to Lambda Parameter

c++

lambda

gcc

capture

gcc5