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    <head>
      <base href="http://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 --- - Union not returned correctly"
   href="http://llvm.org/bugs/show_bug.cgi?id=18726">18726</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Union not returned correctly
          </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>MacOS X
          </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>LLVM Codegen
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>ishiura-compiler@ml.kwansei.ac.jp
          </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>Clang 3.5 (based on LLVM 3.5svn) for x86_64 target miscompiles the following
code.

    $ cat error.c

    union U { long m0[3]; long double m1; };

    union U func(void)
    {
        union U x = {{1,1,1}};
        long y = x.m0[2];

        return x;
    }

    int main(void)
    {
        union U ret = func();
        if( ret.m0[1] != 1 ) { __builtin_abort(); }

        return 0;
    }

    $ clang error.c -O2

    $ ./a.out
    Abort trap: 6

The value of ret.m0[1] was 140734836113409 instead of 1.
There was no problem with an i686 target.

    $ clang -v
    clang version 3.5 (trunk 200763)
    Target: x86_64-apple-darwin13.0.0
    Thread model: posix</pre>
        </div>
      </p>
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