<html>
    <head>
      <base href="https://llvm.org/bugs/" />
    </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() calls memmove on nontrivially-copyable type"
   href="https://llvm.org/bugs/show_bug.cgi?id=28527">28527</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>std::copy() calls memmove on nontrivially-copyable type
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>3.8
          </td>
        </tr>

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

        <tr>
          <th>OS</th>
          <td>Windows NT
          </td>
        </tr>

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

        <tr>
          <th>Severity</th>
          <td>normal
          </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>aaron@aaronballman.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Consider the following snippet:

#include <algorithm>

int main() {
  volatile int *v1[100];
  volatile int *v2[100];

  std::copy(v1, v1 + 100, v2);
}

This results in a call to memmove() rather than copying individual volatile
elements of the array (<a href="https://godbolt.org/g/b0fv3R">https://godbolt.org/g/b0fv3R</a>). This should be handled a
bit more kindly, since volatile-qualified types are not trivially-copyable
types ([basic.types]p9 states in part: "Cv-unqualified scalar types, trivially
copyable class types (Clause 9), arrays of such types, and nonvolatile
const-qualified versions of these types (3.9.3) are collectively called
trivially copyable types.").</pre>
        </div>
      </p>
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