<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJylVU2T2ygQ_TXyhRqXhGzLPugwY-_M-rC1l2ztcQqJlkUGgRaQneTX70OynbEnySUqfQDdPF4_ulFl5ddyz2rRERO1s96z0CrPTq3SxE7WvSlzYNawNoTeJ_ljwp9xH1Roh2pe2w4dKUwnHBp139ct1W9o9oPW-ORFtpon6S5JH6f3Pz7iJavUBxnR8kcfBGasUqYM22oB6wngYEFMUiMGHW7cJf03UHSvMI2MZCDbWUeMvvRkvDoSpgrDpI0LeRthX7bbOduHhBeeicoOgWVpwpfMa3siB5MZl6uFJ_YDLfbsJOJECBIs8z2RnAxDz4YP8RypDtZNAflAQs7Zp1YEIIZBaP2VtaR7IFQWUULAHkI7zyqwmsLvnW1UgMcYVuNsFyMKNzJ-Al34gVIXBYjs33N43UWVXisElOTbo1Uy4di5Lbt6gImtRST63Z7_wfCcEf56VUYFJbT6Rq-d6BO-HiDvwYCYtuaQ8E2MEXlSt1FgCE6eGRvYgQw5ESgqP8pqJbEH5onuk8jKyuowtw5oz9_wHDO5efEv5t-bYP8kR-PeeYud8aLr9Rl1D_3Bp7FuUk2rS_qA28PfPDIUyBF8a0R8cMpItCODd_hxZLyRv-cRnitT6wFLQJ8pQ6HMuzn0JZAzLErHGmgT5ZjMxdPUYOfrLtFv5PYBAx_83-b94FuAGhRRH1zEvnglxe49DWUC64Qyv2QQ5YFD9FWIZ8cgwNPY3KIQ4hX7CX_Cra4wl9kf4K6w50XvA7ijeBl2FAYolv4glIv-Nxlug9Bs7657NRUHvBY5MrnYpPGdF9dpMQfRyTejdYH3ehETYCbLXG7yjZiJIbTWlY1ydBJHmg1Ol7841rQ-Xj4PyK7PqGt0lfcDeTSWOV8Vs7bMmnwlpMzyim_qqq5Wq0byKsubNeWiKuRMi4q0L5Ml9OWGTmyEQDtZ7ma_z0CVPOU8zbJ1tkyzxXouFnmxTJuab3haF8UmWaSEHNHziBOLbebKEbIaDh5GrXzw343Cj1VOI2EwDCpoKu_OX_58m9YoRxx2bqiDwr_iJ0cydmg2ki9H5v8DdcXu7Q>53267</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            std::deque/std::stack construction is more expensive than GCC
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          firewave
      </td>
    </tr>
</table>

<pre>
    I came across this while working on https://github.com/danmar/cppcheck/pull/3716.

Using `std::stack` in Clang with the default `std::deque` backend is more expensive than doing so in GCC. It's about 10% slower. In the case I came across this I was able to speed this up using `std::vector` instead. That actually helped both compilers but Clang profited more from that.

The problem is the `std::_Deque_base<void*, std::allocator<void*> >::_M_initialize_map(unsigned long)` which GCC does not generate in the code - see https://godbolt.org/z/v1d9GsGnW.

Here's some sample code I used for profiling with `-O2` and `callgrind`:

```cpp
#include <stack>

extern void f()
{
        std::stack<void*> stk;
        stk.push(nullptr);
}

int main()
{
        for (int i = 0; i < 100000; ++i)
        {
                f();
        }

        return 0;
}
```

Total Ir:
Clang `43,790,737`
GCC `39,794,842`
</pre>
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