<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/129201>129201</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [alias] will bring in correctness when 2 objects part overlap
        </td>
    </tr>

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

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

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

<pre>
    * test: https://godbolt.org/z/Peb3G1zWx
```
typedef struct {
    int a;
    int b;
} S;

S g_info;

__attribute__((noinline))
int foo1(S * s)
{
 int start = g_info.a;
   s->b = 0;
   int end = g_info.a;

   return end - start;
}

```

* Now both gcc and clang think **s->b** will not alias to **g_info.a**, so start and end are same value, and return 0 derectlly.
 But when &g_info  and s are part overlap, **s->b** and **g_info.a** may be point to same address ?

 - I already use -Wall to report all warning, but the **dangling pointer** is not identified by clang
</pre>
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