<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/152241>152241</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            perl 5.40.2 fails to run simple script when compiled with Clang-21.1.0-rc2
        </td>
    </tr>

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

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

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

<pre>
    I use yocto to build a system using clang as default system compiler. When using clang-21 RC2, resulting perl is not working correctly. A simple reproducer is

```perl
perl -e 'use Getopt::Std;'
```

instead of executing successfully results in

```
panic: magic_killbackrefs (flags=0) at /usr/lib/perl5/5.40.2/warnings.pm line 620.
Compilation failed in require at /usr/lib/perl5/5.40.2/Getopt/Std.pm line 4.
BEGIN failed--compilation aborted at /usr/lib/perl5/5.40.2/Getopt/Std.pm line 4.
Compilation failed in require at -e line 1.
BEGIN failed--compilation aborted at -e line 1.
```

This happens on x86_64 and also on arm64 targets.

If perl is built with `-Doptimize='-O2 -fno-strict-aliasing'`  added to configure then it works correctly. It also works file when using just `-O1`

I do not have a narrowed down reproducer than this yet. 
</pre>
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