<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/133984>133984</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            MemcpyOpt doesn't strip TBAA correctly
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
      </td>
    </tr>

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

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

<pre>
    While debugging https://github.com/JuliaLang/julia/issues/57959. It got minimized to what looks to be a bug in MemCpyOpt, where it strips the noalias attribute of a memcpy https://github.com/llvm/llvm-project/blob/3c7a0e6c826b8bcfa4ec6154fd4247658ca3a03f/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp#L1682-L1688 but not the other aliasing metadatas (tbaa,tbaa.struct). Probably using `combineMetadata` as used elsewhere in the pass
@khei4 was the one that originally added this optimization
</pre>
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