<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/69210>69210</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            wrong code at -O1 and above 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 seems to be a recent regression. 

Compiler Explorer: https://godbolt.org/z/Ee8M1Ge3e

```
[535] % clangtk -v
clang version 18.0.0 (https://github.com/llvm/llvm-project.git f41ec27f7eba34548a280a4a4d7de2ef32837210)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /local/suz-local/opfuzz/bin
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
[536] % 
[536] % clangtk -O0 small.c; ./a.out
0
[537] % clangtk -O1 small.c; ./a.out
2
[538] % cat small.c
int printf(const char *, ...);
#pragma pack(1)
struct {
 int : 1;
  int b : 18;
  int : 12;
  int c : 8;
  int : 23;
} d;
unsigned short a, e, f;
static long g = 1;
int h;
void l(long *i) {
  char j = f;
  h = ~(1 && g);
  d.b = ~((h ^ e) | j);
}
int main() {
  l(&g);
  for (; a < 1; a++)
 printf("%d\n", d.c);
  return 0;
}
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJy0VU2P4ygQ_TXkUoplg79y8CEf49EcVnvYva8wlB26CUSAu3v7sL99BUk76cxopJVmpcgxRb3H41EuuPdqMogdqXakOqz4HI7Wde9HNNKayc-rwcq_u28BPOLJQ7AwIHBwKNAEcDg59F5ZkwHJDyTfXp57ezorjQ6-vJ21degI28IxhLMnbEtoT2g_WTlYHTLrJkL7d0L7L9j-VnxFhvdMpM6vv8uw2lWsItUBCK1AaG6m8Azrl8tsGsMLuqgIijbLsxwIbR9WVuE4D5mwJ0J7rV8-_tZnZ59QhGxSAcayQEGbscGBs7IqW07bnJe8lI1EiiOjLWtokRO6uaz9J3cThrjPt7b-qy7Xs3k29tWstTLz23oy8zXv6JBLOFmJOmafrVdvl6lvxgeuNcqDSoZFXVZwTWjv5_f1x7s9j_N7NGxQ5gLs7WwkCG6kkjwgfN3vQV3IeFDWXMlm7yKlGqIJQhDaX6XeJNK-yP8HzuLXc15t_wM1ioDyl-jbL8pOsw4qotgWMsJ2pMxPdfmw5M-SUqHWH4X6o9hSvL_n4E9c60wQtoOM0J5ndg4XzH3dN99Di59A6R20XaA8LJA0rUyAs1MmjIS2whofQBy5A0K3hO4hy7JY4mx3JaPs7Ph04nDm4pnQtlg-AB_cLAKQ5poKkTlaUyxoSLHhEm0fwilIH4IihX-UStlNVHMAuYxmk1qaBH-0LgCPu8D4GJcUH3hQArQ1E0xA2OFOY-Q_LqMXqyRoQtuUS-hWEbq52-PFq6fEMd6pPKbIP9EgILQmtIbp3kcAmQ1LTmxRQKovUWdk38PTJ9Obw03biSuTIJ9k6BSqH9YYbTzH6B5wIGyfthkd2aXf9eBux08oJbSSpNqb9LoHmYnPlA7D7Azk34tbOvVKdkxu2IavsCvqTVPW1Ya1q2NXlTJvpRxl3TLESrJ2HOohb0U9oOA5W6mO5pQVeVEXZdFWbcboKMo6LwdsGqxzRsocT1zpLPbreHWslPczdvWGFvlK8wG1T1cZpQZfIU3GnVSHletSjx_myZMy18oHf2MJKmjsXl08ZGElAg_p4-JGAh_sC4I18Ng4YDU73f23u4XQPonyhPZJ9L8BAAD__6r8Iz0">