<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/147149>147149</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [libc++] Deducing this in string_view with LIBCXX_ABI_UNSTABLE
        </td>
    </tr>

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

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

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

<pre>
    One of motivating factors for Deducing this was [performance](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p0847r7.html#by-value-member-functions-for-performance
)

Would it be reasonable to implement `string_view` variant that uses Deducing this when users specify `LIBCXX_ABI_UNSTABLE`? 
I understand this might require some benchmarks(both runtime and binary size on large projects) before we conclude it is best to do switch, but I think it might be interesting thing to do since `string_view` is heavily used. 





</pre>
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