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    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - std::copy to memmove optimisation seems to not work."
   href="https://bugs.llvm.org/show_bug.cgi?id=40575">40575</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>std::copy to memmove optimisation seems to not work.
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libc++
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>All Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>denis.yaroshevskij@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>std::copy has an optimization to memmove but it doesn't seem to work:
<a href="https://gcc.godbolt.org/z/a6lvSm">https://gcc.godbolt.org/z/a6lvSm</a> (no memmove)

I has real consequences:
libstdc++: <a href="http://quick-bench.com/vpLxYCWfverSzlWxFjwuXxELD8Q">http://quick-bench.com/vpLxYCWfverSzlWxFjwuXxELD8Q</a>
libc++: <a href="http://quick-bench.com/kfsPjkSo79hHiy0ZVrMCn7wU6Xw">http://quick-bench.com/kfsPjkSo79hHiy0ZVrMCn7wU6Xw</a></pre>
        </div>
      </p>


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