<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/96047>96047</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [mlir] Do not generate sizeof expressions using GEP
        </td>
    </tr>

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

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

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

<pre>
    Lowering MemRef to LLVM dialect currently generates `ptrtoint (getelementptr null, 1)` style sizeof expressions using this helper:
https://github.com/llvm/llvm-project/blob/cfb4dce90ce66acbd094e443f422c4e5c413a9e8/mlir/lib/Conversion/LLVMCommon/Pattern.cpp#L171-L184

These need to be replaced with an emission of a constant based on the DataLayout.

The ability to generate the expressions in this form will go away entirely with https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699 and causes problems for https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179 as well.
</pre>
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