<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/66216>66216</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [WebAssembly] Incorrect code generated after enabling tail-call
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          slavek-kucera
      </td>
    </tr>
</table>

<pre>
    I've recently encountered a problem while compiling for the WebAssembly target after enabling a tail-call optimization (`-mtail-call`).

I believe I've managed to reproduce the issue with the following code:

```
struct X {
    char a[124];
    int b;
};
const X global = {{}, 5};

int __attribute__((noinline)) g(X x, X) {
    volatile int i = 0;
    return x.b;
}

int f(X x) {
    return g(x, global);
}
```

Commenting out the volatile variable `i` in the `g` function changes the return value of the `f` function.
My understanding is that the __stack_pointer adjustment at the end of `f` leave the prepared arguments below the stack pointer address where they are overwritten by the store in the `g` function.

https://godbolt.org/z/dvMG9xde9

The code seems to be generated this way since release 15 (https://godbolt.org/z/x4TY57861)

</pre>
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