<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/147049>147049</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [DAG] foldABSToABD - add value tracking pattern matching
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            llvm:SelectionDAG
      </td>
    </tr>

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

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

<pre>
    This is currently limited to (ABS (SUB (EXTEND a), (EXTEND b))) style patterns, but we can also fold to ABDS/ABDU is there are sufficient signbits / known zero signbits.

ABDU alive2: https://alive2.llvm.org/ce/z/Aqx5p2
</pre>
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