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    <head>
      <base href="http://llvm.org/bugs/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - No -Wsequence-point warning for undefined behavior in "a[*p] = (*p += 1)""
   href="http://llvm.org/bugs/show_bug.cgi?id=18803">18803</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>No -Wsequence-point warning for undefined behavior in "a[*p] = (*p += 1)"
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>trunk
          </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>Frontend
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>chengniansun@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvmbugs@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I suppose there should be an undefined behavior on *p. Gcc warns this behavior. 

$: cat s.c
void fn(int* p) {
  int a[2] = {1, 2};
  a[*p] = (*p += 1);
}
$: clang-trunk -Wsequence-point -c s.c
$: gcc-trunk -Wsequence-point -c s.c
s.c: In function â€˜fn’:
s.c:3:15: warning: operation on â€˜*p’ may be undefined [-Wsequence-point]
   a[*p] = (*p += 1);
               ^
$: clang-trunk --version
clang version 3.5 (trunk 201116)
Target: x86_64-unknown-linux-gnu
Thread model: posix</pre>
        </div>
      </p>
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