<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/133685>133685</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Flang][OpenMP] only assertion-enabled flang can reach llvm_unreachable (cancel directive)
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            flang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          k-arrows
      </td>
    </tr>
</table>

<pre>
    Reproducer:
```f90
program test
!$omp cancel parallel do
end
```

With assertion-enabled flang, the following output is obtained:
```txt
Unexpected directive
UNREACHABLE executed at /path_to_project/llvm-project/flang/lib/Semantics/check-omp-structure.cpp:2521!
```

The location of this llvm_unreachable is:
https://github.com/llvm/llvm-project/blob/809f857d2c8edffe1dac317982b68a467710f877/flang/lib/Semantics/check-omp-structure.cpp#L2521
</pre>
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