<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJylkk2P0zAQhn-NcxlR5aNN20MOLQsS0iJQQex5bE8SL45d-aMV_HrsZLtbIW5IjuOZsV8_nhlu5a9uDOHsWXNg9cc0Biu51WFl3ZCs3-nrd0-E9Pz1wsoHVh6W-WkkA1cC4QgDARqwMWhlSEIfjQjKprAKI7C2nKIPAZVOS-idnQCz119VP7uFyAGBWpNj9fusOlC4vyzFX8ZsCjTGBhgiOjSBCLLKLAAyJsvCpPyEQYyJJruVGUBY8_IAgBvQcuYOBC5WSWDrN-R6x-r9cu7x8cdn-HA6fTmlZMHR2Z8pBZOVURP0NhqZ4YWdzkrj_H7k1gVK7uqfz1jm76PyiSPtPp8JHVxzYheVjK3RDQTfMiKcnR0cTn5JbBgJPp1uaXdABrkmuSpk18h9s8cCYxit66wzGLCITv9d6iQT-SpdlgytL7ffu3TRM4mQTOV9JJ8Wm3VZb4ux22DTkhQ9tpu13PJ21yDvOVaSypLkti00ctK-Y5sjq-tZtDkIh35MJts8FP8Pobq6rPNoqn2zrjarsl_zesv5rq2o2rdVqh9NqXirrJMbuXDdLMnj4FNQKx_8WxC9V4MhmpkTYVBBU3ef2gs51SuxVHWhWWrw2kisPt73UTFv6mbeP_jiHA8>54027</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            IR outliner verification issues with musttail + swifttailcc
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            llvm:crash
      </td>
    </tr>

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

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

<pre>
    https://godbolt.org/z/f8WeaejPv

When we create an outlined function with `musttail` from a `swifttailcc` caller, we get

```
cannot guarantee tail call due to mismatched calling conv
  musttail call swifttailcc void @musttail()
LLVM ERROR: Broken module found, compilation aborted!
```

This can appear when compiling large Swift programs with the IR outliner enabled.
</pre>
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