<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/77482>77482</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang C++20 coroutine miscompilation
        </td>
    </tr>

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

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

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

<pre>
    I have generator coroutine, I just added [[gnu::pure]] for my constructor

```cpp
struct A {
  B* ptr;

  [[gnu::pure]] A(B& b) : ptr(std::addressof(b)) {}

};

```
This provokes segfault on this code:

```cpp
dd::generator<int> foo() {
 co_yield 0;
}
int main() {
    for (int i : foo())
 ;
}
```

I had minimized code and in minimized example there is link between [[always_inline]] on await suspend and this segfault (yes i know how clang coroutines work, but i feel that problem not here or not only here)

So, here minimized code:

https://godbolt.org/z/Eadnefe1v

I tried to understand what happens and where exactly bug, but its strange

Locally reproduces even without [[always_inline]] (clang 17 (not clang-cl) windows 11)

May be inline in final awaiter await suspend (its interesting when final_awaiter is promise itself), may be in combination, may be its really just [[pure]] attribute forces compiler to 'forget' to call constructor and initialize memory

Full code:

https://godbolt.org/z/rd167d79q

(segfault locally)


</pre>
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