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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 - NewGVN miscompile and crash"
   href="https://bugs.llvm.org/show_bug.cgi?id=49873">49873</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>NewGVN miscompile and crash
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libraries
          </td>
        </tr>

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

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

        <tr>
          <th>OS</th>
          <td>Linux
          </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>Scalar Optimizations
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>ruiling.song83@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=24727" name="attach_24727" title="IR reproducer">attachment 24727</a> <a href="attachment.cgi?id=24727&action=edit" title="IR reproducer">[details]</a></span>
IR reproducer

NewGVN fails to add extra dependency when processing an icmp with one operand
being phi-node. it tries to evaluate a phi-of-icmp and later one of the icmp
proved to be constant based on a previous predicate, see the code after big
piece of comment in NewGVN::performSymbolicCmpEvaluation(). We need to make
sure the dependency between the real instruction and the predicate condition
was added.
opt -S -newgvn -o - reproduce.ll</pre>
        </div>
      </p>


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