<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/124255>124255</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            LLVM ERROR: Don't know how to widen the operands for `INSERT_SUBVECTOR`
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            backend:X86,
            crash-on-valid,
            llvm:SelectionDAG
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
            abhishek-kaushik22
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          abhishek-kaushik22
      </td>
    </tr>
</table>

<pre>
    ```llvm
define <8 x i32> @foo(<8 x i32> %a, <2 x i32> %b) {
  %result = tail call <8 x i32> @llvm.vector.insert.v8i32.v2i32(<8 x i32> %a, <2 x i32> %b, i64 0)
  ret <8 x i32> %result
}
```

https://godbolt.org/z/x6qnfPM7W

We get a fatal error in `DAGTypeLegalizer::WidenVecOp_INSERT_SUBVECTOR` for this seemingly simple code.
I'm not sure how this could be fixed. Can we just replace the `INSERT_SUBVECTOR` with a series of `INSERT_VECTOR_ELT` nodes?

There's also #102016 for AArch that also looks like the same problem as this one.
</pre>
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