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      <base href="https://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 --- - musttail calls are not allowed to precede unreachable" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D23766&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=qWoYOx-jxFTSa7K7hMMb37fCahH6dTa_-YmPVOlgvZI&s=RKGnUxmCWmyldI1aNC_i5fNwHD-KPD5yrHObSrWmqRo&e=">23766</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>musttail calls are not allowed to precede unreachable
          </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>All
          </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>Backend: X86
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>kavon.farvardin@gmail.com
          </td>
        </tr>

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

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

declare void @g() noreturn

define void @f() {
entry:
  musttail call void @g() noreturn
  unreachable
}


llc rejects this with the following error:

musttail call must be precede a ret with an optional bitcast
  musttail call void @g() #0
llc: musttail.ll: error: input module is broken!


A conversation on IRC led to the conclusion that `unreachable` following a
`musttail call` should be permitted.</pre>
        </div>
      </p>
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