<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/62984>62984</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang-17 crashes at llvm::SelectionDAGISel::Select_READ_REGISTER
        </td>
    </tr>

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

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

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

<pre>
    The bug triggering code:
```
register long data_0 asm("rbp");
long data_3;

long foo_data = 0;
long foo(void) {
  long v = 0, i;
  long t, u;
  foo_data;
  i = data_0 == data_3;
  t = data_0 + data_3;
  u = 5;
  return 2 * t * 5;
}
```

When compile it with `clang-17 -O1`, clang-17 crashes:
```
$ clang-17 -O1 small.c
small.c:28:2: warning: expression result unused [-Wunused-value]
        foo_data;
 ^~~~~~~~
fatal error: error in backend: register rbp is allocatable: function has no frame pointer
clang-17: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 17.0.0 (wierton@114.212.81.121:~/llvm-project-trunk 806dea46be4c49dc587b98dab5e4d9d242a6abdb)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
clang-17: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-17: note: diagnostic msg: /tmp/small-7a99ee.c
clang-17: note: diagnostic msg: /tmp/small-7a99ee.sh
clang-17: note: diagnostic msg: 

********************
```

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJysVU1v4zYQ_TX0ZWBDpr4PPihrOxsgaBaJiz0GlDiW2dCkwA8nvexvL0jZirNpgaJbQRDIN2845Mw8ilkreoW4IvkNydcz5t1Bm9WrQOO0mrWa_7naHRBa34Mzou_RCNVDpzmStCHJmiQNKZLzG6cGe2EdGpBa9cCZY88JMHsktCKUmnYglBJak_Rm5L_T0gm7suy1fg5WIOkako9ee60JrU5acEJrIOXZBmPo09mFfgEx-Z1tLqD-Cr2EuYJE9D8fgKTraZZekdwHEr35zPCRkV8hBp03CigQ2oQFaHNlJuX6b9M6fr8fUEGnj4OQCMLBq3AHIEXSSab6-bKE-cMyuNAvMEGdYfaA9p_qRWgG1-5gj0zKRTdaL5O0oVX4kLSBV2aUUH0Y4ttg0FqhFRi0XjrwylvkQPKb-fdxPD8x6ZHk68v5x-dzxkm--TE-I7BnjklAY7SJscIAhIKWdS-oeMCmZjPtAMICk1J3zLFWhv6EvVedC5s7MAtKw96wI8KghXJoxiCXo08RwiCCsDdaOVQ8JPzIFIc9ExL5mHR8Ey7qAMpQ-MpbhPkJnAaLCEKdwj6EVqHV3wPBCU3M1rJcJIvoeNYayZLlMlvQJV1Uy8WSLkna_CB0K-XpOB-M_gM7N3fGqxeokoIjy4oWsy6reZdXZVtXnLU5ZrzmNKOsYC1vp9A7Znp04WBvVfFcZHOvXpR-VXMplH-b98qfeQeDjMNRc5SBPWgr3kbTnbKOSYl8LWKGCN16awjdtkJ9TqTSLuafC9YrbZ3o4Ghjw1x67hfeKzl8u980Txtodrvmy1fYfd3A9uH-_uH73W-3sL273zzB7iHCN7_fwuPm28PjbpLBN4OD0R3a0K5We9MhoZUNN0moNbNWd4I55GC8AtsZMbiJYBBioyEH5qYl_2UK6NYdB0K3UVvzktU14kVvv7KEPfyHSvxf9fh4qcz4KuV1WrMZrpZFladFSot0dlixrqyrMttXvKxoVxbdvshYxXhR8SzPi3QmVjShaZLTeklpmaULnmW0rPZplZZFm7GMZAkemZCLoIyFNv1MWOtxVdC6ymaStSht_J1RqvAVojH8cvL1zKyimlrfW5IlUlhn31dxwklc_XxrAnMQKKHGafOEEuOFsm5u756iSCb0-XHTrJ8fN7d3T7vN48wbuTo4N8R7l24J3fbCHXy76PTxLOuf1E3oNm7WErqNh_krAAD__wx2OPI">