<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/64025>64025</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang fatal error in backend
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          anbu1024
      </td>
    </tr>
</table>

<pre>
    clang version
```
clang --version
clang version 16.0.6
Target: x86_64-unknown-linux-gnu
Thread model: posix
```

Test case:
```

int foo(int a, unsigned char *b)
{
  int x = 0;
 b = __builtin_assume_aligned(a, 16);
  for (int i = 0; i < a; ++i)
 x |= b[i];

  return x;
}
```

```
fatal error: error in backend: Cannot select: 0x56295ee522b0: i64 = bitcast 0x56295ee52160
 0x56295ee52160: i32,ch = load<(dereferenceable load (s32) from %ir.3)> 0x56295ee520f0, FrameIndex:i64<0>, undef:i64
    0x56295ee51c90: i64 = FrameIndex<0>
    0x56295ee51d70: i64 = undef
In function: foo
clang-16: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 16.0.6
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /llvm/16.0.6/llvm-project-16.0.6.install/bin
clang-16: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-16: note: diagnostic msg: /tmp/mini-06d74d.c
clang-16: note: diagnostic msg: /tmp/mini-06d74d.sh
clang-16: note: diagnostic msg: 

********************

```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJy0VU2P4ygT_jXkUkrkgD-Sgw_58kxLrbdbM3m1xwhDOWEHQwS4O_vvV-B0Oj07Gq12diUfysVTT8FTVcC9V0eDWJNiTYrthA_hZF3NTTvMM5pPWiv_qIXm5ggv6LyyhmRbkq1ImV2_9DsiptMPmA9hMC9n2awcV_bcHTEQtoLLojyU-XQw34x9NVOtzHCZHs1wxZ0ccgm9lagj-my9uvxwA1c8-gCCeyRs9ROYMgE6awldRIsTuoHBJB0kiBN3QOiqJXR5janWowEQ4RcgbAsZYW_eNjkOh3ZQOihz4N4PPR64ToSELlKCeRkJb0HQ2ZgmbUDdGJO5AR5NQteErtVtGzFxtYnIlhRrRYrtje2N02EYnIHL-0K1_YkM3zk7HrgGdM66qHUyQBloufiGRkbfhhtjA3jUKFL5sktR0mWBWFDaZtGjyjwdp1VBcB_uEfO3TN87YxijhG7EKcVqyyVhG0IXEh126NAI5K3GtBJl8xG-hM7ZHggtlJuxJO_unjrrsqh843iPD0bihbCVKnPCNhlhu7HqErur96oh3DHMxfLDme6ZRo4fBcnqQ9CYIwEfDHSDESFOCFulFnwflOm8vMkejXF6OmdNQCNB2L7nRkLHlUYJryqcAC8qgLASocqiKoNHmL5AsOARQZkXK3hK9tZD_-lEPhgfuNYotyodgNBG65ee0OaaaPyfnp39HUWYjt6ZGsMIbVpl_qqHsSFOM0jFj8b6oAT0_pj4xyamv_DdDcPz4271dQer_X61-Qz7zztonh4fn357-N8naB4ed19h_5Tc6_9_gi-756cv-9sl8-zw7KxA71GCt4MTGHs0dmgsGffeCsUDSnCDAS-cOocbwMWuFmmVhxvl35SANqE_E9r0yqhpVsoqlzPxywz-9A_q8K9W43Y1TWTN5JIt-QTreblYLpdVNS8np5pjxXJBKeskK0ueUy7bgraYl8WyWOTtRNU0oyyrKM1YvmDlrMhz5POqbRliWcmO5Bn2XOlZ7MqZdceJ8n7AuswzWkw0b1H79CxSavAV0iKhNL6Srk6d3A5HT_JMKx_8O0tQQeP1zby7U--u0sngdH0K4exjvWlDaHNU4TS0M2H797G5nxZCm7QBT2iTNvhnAAAA___oLjKN">