<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/135998>135998</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [X86][AVX2] X86FixupVectorConstantsPass - performance regression
        </td>
    </tr>

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

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

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

<pre>
    Moving ISPC from LLVM 18 to LLVM 20, I have encountered performance regression for a few of our benchmarks for ISPC target avx2 (corresponds to `-mcpu=haswell`). It seems to be caused by #122601. It is around ~20-25%, as measured on Intel CPUs i9-12900 and 8360Y.

Compiler explorer link: https://godbolt.org/z/qx8s6K6br
</pre>
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