<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/59138>59138</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Backport 26068c6e6032 to release/15.x
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

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

<pre>
    This fixes an issue when compiling libc++ with gcc, as described in https://reviews.llvm.org/D13546:

> [libc++] <type_traits>: Avoid instantiating a pointer type.
> 
> GCC expands the pointer type in this conditional expression even for template types _Up that are not arrays.  This raises an error when std::decay<> is used with reference types (as is done in LLVM's sources).  Using add_pointer<> causes GCC to only instantiate a pointer type for array types.

</pre>
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