<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/143234>143234</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [flang] Use of precompiled headers leads to undetected missing includes
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          mgorny
      </td>
    </tr>
</table>

<pre>
    I do realize that @mrkajetanp did introduce precompiled headers to reduce memory usage on my request in #131137, but looks like we missed a major problem with them: they hide missing includes, so now buildbots remain green when a code with missing includes is committed, but the end user builds without PCH fail.

Perhaps we should disable PCH on (some of the) buildbots via `-DCMAKE_DISABLE_PRECOMPILE_HEADERS=ON` to catch issues.

See #143196
</pre>
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