<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/81286>81286</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [libc++] Remove _LIBCPP_ATOMIC_ONLY_USE_BUILTINS setting
        </td>
    </tr>

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

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

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

<pre>
    As discussed in https://github.com/llvm/llvm-project/pull/76647#pullrequestreview-1872878710:

> We agreed that `_LIBCPP_ATOMIC_ONLY_USE_BUILTINS` seemed undesirable. Indeed, the goal of that setting was to decouple libc++ from libraries like compiler-rt and libatomic in Freestanding mode. We didn't have a clear understanding of goals and non-goals of Freestanding back then, but nowadays we do have a better understanding that removing all dependencies of libc++ in Freestanding is a non-goal. We should still be able to depend on builtins like those defined in compiler-rt for implementing our atomic operations under Freestanding. Hence, it makes sense to remove this setting (which should not have wide usage anyway).
</pre>
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