<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/129538>129538</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [RISCV][EVL] Improve sdiv/udiv code generation for tail folding by EVL.
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            backend:RISC-V
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          Mel-Chen
      </td>
    </tr>
</table>

<pre>
    After https://github.com/llvm/llvm-project/pull/127180, the vectorizer emits vp.merge + general sdiv/udiv instead of vp.sdiv/udiv for tail folding by EVL. 
However, using vp.udiv/sdiv may yield better performance. The improvement could come from fewer vsetvli instructions and lower vector register pressure.

The current IR and assembly for sdiv: https://godbolt.org/z/YvPhGa8df
The vp intrinsic IR and assembly for sdiv: https://godbolt.org/z/1achsE3Wo

Not yet sure at which stage this optimization should be applied. We need more discussion.
Label it as RISCV backend issue for now.

</pre>
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