<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/95691>95691</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            fatal error: error in backend: Cannot select: intrinsic %llvm.preserve.union.access.index
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            backend:X86
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          dcb314
      </td>
    </tr>
</table>

<pre>
    From the clang testsuite, file ./CodeGen/bpf-preserve-access-index.c
does this with recent clang:

test $ /home/dcb40b/llvm/results/bin/clang -g ./CodeGen/bpf-preserve-access-index.c
fatal error: error in backend: Cannot select: intrinsic %llvm.preserve.union.access.index
clang: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 19.0.0git (https://github.com/llvm/llvm-project.git 7cb5faf6da5a6f6335aca8a2532e5320ec434458)
Target: x86_64-unknown-linux-gnu

[bpf-preserve-access-index-47d72d.c.gz](https://github.com/user-attachments/files/15856636/bpf-preserve-access-index-47d72d.c.gz)
[bpf-preserve-access-index-47d72d.sh.gz](https://github.com/user-attachments/files/15856637/bpf-preserve-access-index-47d72d.sh.gz)

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJy0lMuOnDwQhZ_GbCwQ-AYsWMxF_C_wL7KLjF2AM8Zu2aank6eP3KjTk0VGM1KywcgCf6dOHZeM0SwOYED8EfHnQu5p9WHQaqINKyavvw9j8BtOK2BlpVtwgpjibhIg8oRnYwFXiIxPXsN_4BAZp9NcngJECGcopVIQY2mchkulUP2M6gftIeK0mohfTVpxAAUuHYcj-nB8czwzCiPCMCLj6jdAZNRqYvWEyGjteUNkDBB3m2Lmmkw_NJbLZ0XNMkmLIQQfEH04XrBxeJLqBZzOe0_SOZ9wBAsq5Q3jUjAuGoUR4VlPdUNUuzPeVQeouoIOzK3KO-kQPAfvEjiNld826TSepbGgD4fgYhJWXgNua4xIt0fA5RknjyMANu7slUzGO0T6NxR8hhCNd7jpq7qqF5Ot7NaUTjHbTEZExsWkdZ8q5be7o3kpT8F_A5Wq_FerJj7LWWjJpZgFpVwq2UnCKQFOSQ2KUcZ49wv_vwwLXB26dOKrYOXuXpx_daU1br-Ui9vfNhnxxz92p2StbomuVLX8QPz5ff17hFDKlKRaN3DXTOR45rXhHReCiveS8BvrVspHxMX176hrP6LugN3kFXqguqe9LGBo2qbjhPd9U6yD7ibR1bwVem6JIpoKqjXjTTMJzYA3hRlITVgtGlF3Tc-binPKKWfAurkRUtWI1bBJY6trsH1YChPjDkPPRd8UVk5g43VoEHK_I186gQjJcyQM1xxN-xIRq62JKd5PSiZZGP75lSv2YIfPBR6R8VpmbstR6XkgPwMAAP__9GqokA">