<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/129203>129203</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [register] clang use  redundant mov to avoid clobber return register w0
        </td>
    </tr>

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

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

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

<pre>
    * test: https://godbolt.org/z/PG9GoMnqo
```
typedef struct {
    int a;
 int b;
} S;

extern S g_info;

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

   return g_info.a;
}
```

* Now gcc store the  s->b first and then can load g_info.a into return regiser w0 without redundant mov 
  While clang need the redundant mov as it load g_info.a first, and the register w0 is not released.
  
 - I already use -Wall to report all warning, but the **dangling pointer** is not identified by clang
</pre>
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