<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/86261>86261</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Miscompilation of `store undef, %ptr` (or an Alive2 bug?)
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
      </td>
    </tr>

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

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

<pre>
    Alive2 link: https://alive2.llvm.org/ce/z/-6JYLW

InstCombine folds:
```llvm
define void @src(ptr %p) {
  store i8 undef, ptr %p
  ret void
}
```
to
```llvm
define void @src(ptr %p) {
  ret void
}
```

But Alive2 told me that it's not a correct transform. AFAIK, the semantics of `undef` is like uninitialized value in memory. I'm not that sure whether it's a LLVM problem or an Alive2 problem, so post an upstream issue first.
</pre>
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