<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/134549>134549</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            DebugInfo: preferred_name causes DIDerivedType node to be emitted twice
        </td>
    </tr>

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

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

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

<pre>
    This is a problem isolated from one of our own test cases: `clang/test/CodeGen/preferred_name.cpp`

The test expectation captures this, but there is no acknowledgement the bug exists.

Reduced repro: https://godbolt.org/z/dn9hs87ev
```C++
template <class T> struct Foo;
template <class T> using Bar = Foo<T>;

template <class T>
struct [[clang::preferred_name(Bar<short>)]] Foo {};

Bar<short> barShort;
```

Reduced output:
```
!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "Bar<short>", file: !5, line: 2, baseType: !7)
!7 = !DIDerivedType(tag: DW_TAG_typedef, name: "Bar<short>", file: !5, line: 2, baseType: !8)
```
</pre>
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