<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/108698>108698</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            wrong code at -O{2,3} on x86_64-linux-gnu
        </td>
    </tr>

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

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

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

<pre>
    It appears to be a recent regression as it doesn't reproduce with 18.1.0 and earlier. 

Compiler Explorer: https://godbolt.org/z/EGasYh8x1

```
[691] % clangtk -v
clang version 20.0.0git (https://github.com/llvm/llvm-project.git 223e2efa5e886502a9467b7ef700ebce9b7886e8)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /local/suz-local/software/local/clang-trunk/bin
Build config: +assertions
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/10
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/9
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Candidate multilib: .;@m64
Selected multilib: .;@m64
[692] % 
[692] % clangtk -O1 small.c; ./a.out
[693] % 
[693] % clangtk -O2 small.c
[694] % ./a.out
Aborted
[695] % 
[695] % cat small.c
char a[8];
int b = 1, c;
int main() {
 for (; c < 8; c++)
    a[c] = !c >> b;
  if (a[0] != 0)
 __builtin_abort();
  return 0;
}
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJy0VU1v4zYQ_TXjy8CCSH0fdIjtaLGnPbSXngKKHMtsaNIgqSTNry8oOU42DQoU2AKETc48vnlDDkciBD1Zoh6qHVSHjZjjyfn-9URWOTuFeTM69Vf_PaK4XEj4gNHhSCjQkyQb0dPkKQTtLIqAOqJyFCzwJrku3qlZEj7reELWZizLUViFJLzR5DOE_AD53fq7d-eLNuTx_uVinCcPxR2eYrwEKO6AD8CHyanRmZg5PwEfXoEP999E-OPUvrCPTFDn17Euq13dMagOCLxCaYSd4iNun1bvssYn8ksOPM_yLJ90RODtp-A6nuYxk-4MfDDm6e1ve_HuT5IxS7s4L4jTUVTUtnWVc9GVdTM2dGzynEZJ3di0bU0t8G4N_7vwE8WU6ktbP9TldraP1j3brdF2ftlOdr7iTp6EwrNTZBL64oJ-WV3fbYjCGFIHvZxZ0uWkMMCHML9ub3N3jM_C0wf3kvs2-tk-Ah9GbVfC3ayNQunsUU8r4U6EQD5qZ8MKGdxsFUphlVYiEn7b71GvOkSCXXXMwadwekznJyXw4Zrle3Z8YPn_wMl-Pef1xn4jQzKS-iX69jdl59lEnXYVd5hBsYMyP9flp5D_BlrKnL-V-Ve2W-n_YBjOwphMQrHDDPggMjfHD3uKL3iKf_LwG887rHyDfeK9G52PpD4gqy-C3GxSxJ_J5Ul4FFDtWqgOKffFqm3EEaE4IAO-R_mT4yy0BZ4eG0JztePR-fS4U-YSodjjOgW-W8b1lhFxCSYXPUXSxBL8Hop7HG9REPUxsSVovkpnCZ2_Ez08jLM2UdsHkU5g1fOBwFOcvcX8ZoLm8KmPbVRfqK7oxIZ61vC6YF3L282pb7jiBcmjUmqUih3brqlqxhpJ4liWgm10z3Ne5h0rWcGavM14TeLIxFhXou2qUkGZ01lok6VWlhrrRocwU8_ytu7ajREjmbB8HTi39IyLF3iqqY3vl_43zlOAMjc6xPBOE3U01D97ZyeUThGKiNsf0Ow48H0BzQGdxc8vYzN70_-3tgt8WDSFpZMsop96_ncAAAD__1QkAO0">