<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/88361>88361</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [SPGO] The most frequent transition becomes unreachable
        </td>
    </tr>

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

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

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

<pre>
    According to the current implementation of the SampleProfileLoader, we are unable to correctly handle this case:

Assume that `Weight` becomes larger or equal to `std::numeric_limits<uint32_t>::max()`. After the first if statement, we set it equal to `std::numeric_limits<uint32_t>::max()` regardless of the condition.

https://github.com/llvm/llvm-project/blob/1aceee7bb6c4423da73f71aff2004493bdf620d1/llvm/lib/Transforms/IPO/SampleProfile.cpp#L1710-L1723

Later, we add `+1` to the `Weight` and cast it to `uint32_t`, which becomes 0. Therefore, the most frequent edge is marked as unreachable.
</pre>
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