<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/79789>79789</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            【Warning】differences in GCC and LLVM Behaviors about __sync_fetch_and_nand 
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          zhangtianhao6
      </td>
    </tr>
</table>

<pre>
    Differences in GCC and LLVM Behaviors about __sync_fetch_and_nand 
Warning content: 
`warning: the semantics of this intrinsic changed with GCC version 4.4 - the newer semantics are provided here [-Wsync-fetch-and-nand-semantics-changed]`

Demo:
```
void test9_4(volatile int* ptr, int val) {
   __sync_fetch_and_nand(ptr, val);
}
```
https://godbolt.org/z/5r5dbcPaj
GCC use note， LLVM use warning，Why are they different?
LLVM use option -Wno-sync-fetch-and-nand-semantics-changed to suppress alarm，is there a way to modify the code to cancel the alarm?
</pre>
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