<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/131179>131179</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [libc++] Replace uses of `__libcpp_ctz` by `__countr_zero`
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            libc++
      </td>
    </tr>

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

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

<pre>
     For a follow-up patch, we should replace uses of `__libcpp_ctz` in the codebase by calls to `__countr_zero` (there's only a few). This will eventually allow us to clean up `__libcpp_ctz` altogether.

_Originally posted by @ldionne in https://github.com/llvm/llvm-project/pull/122641#discussion_r1972052176_
 
</pre>
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