<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/143140>143140</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [X86] lowerBuildVectorAsBroadcast - remove constant handling
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            backend:X86
      </td>
    </tr>

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

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

<pre>
    Prematurely converting uniform constants to constant pool VBROADCAST_LOAD nodes can prevent further optimizations, but also results in codegen problems such as immediately spilling broadcasted constants (#30679).

X86FixupVectorConstants can handle converting constant loads to broadcasts and other datasize saving formats, including if they are load-folded into a AVX512 instruction.

But without lowerBuildVectorAsBroadcast we are missing OptSize handling - we need some way to unfold constant pool loads that X86FixupVectorConstants would be able to handle if it would reduce total data/code size - this could possibly be performed by MachineLICM which already does similar unfolds.
</pre>
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