<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/59398>59398</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Abnormal `unreachable` in entry
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          younglx643
      </td>
    </tr>
</table>

<pre>
    Hi all, SimplifyCFG makes BB`entry` unreachable, it happens in `simplifyOnce()->removeUndefIntroducingPredecessor()` , I think it's a mistake here, but I don't know how to fix it, can anyone help me?(If we initialize `e` with a value, it works good. e.g. `int e = 0`)
godbolt: https://godbolt.org/z/rb3sjEvhz
source code:
```
int a = 0, c = 0;
static int d[][8] = {};

int main ()
{
  int e;
  for (int b = 0; b < 4; b++)
    {
      __builtin_printf ("%d\n", b, e);
      while (a && c++)
        e = d[300000000000000000][0];
 }

  return 0;
}
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJxsVE2PozgQ_TWVSymRsTEfBw6dZNjt06602vPIQAGeNnZkm850__qVSTrdM1oLiQr13quPlEuFoCdL1IA8gjzv1Bpn55s3t9rJ_Cxysevc8Nb8qVEZA_yE_-jlYvT4dmr_wEW9UMDjEQpGNvo3KBiu1pPqZ9UZSnAdcVaXC9mA2iIULNz5f9megFfA6z2Ib54W90r_2oHGZxu9G9Ze2-lvTwP1FILzN2gKkFSfMc7avqCOwMuAChcdonohnMlvYbs14jMOzgIvI75Yd8XZXTE6HPXPjXbCXllU9s3ZRDMXXAhEC7x6HvFKqK2OWhn9TilrSpGvOs6o8FWZ9aO2q_MvASfnhgPSYTokrLYRCUGckUHBUtbsDOwJeAbyqBc1Ecgz8GqO8RJAPAFvgbdrIL_fvOEw6TivXfrSOxvJxkPvFuBtlsm6ykRZAG85K3KZVTnbD4JzWWS0z6oy3-esKveVrLs9VVVdyb7sZTEcLnZ6ZDK5oXMmgnjCX3O4Ow7OT8Dbd-Ct70T48e11fr8xg1t9T9i7gRLpVlfB7s_2M1Wv7tWnJt9NcbwrRBV1jwk13EYO5LECed5wUB6hPD_An4qLStNzm4Gbq7xjcNOiBwdxdD5B0-fuEX0zT5hvJvDj9tQfFMQveul8_96t2kRtv1-8tnG8xebA5QDyZDfzlIROSElH_MK-ztpQoigEXgAvsP-fkOnc5iR1QrDfz6032-shn7rzpTWInuLq7ZcGfyI-_pfd0IihFrXaUZMVJZMsz4TczY2oej4WYykKntf1oDKeqbIc-moQVDDZ73TDGecZZ1XGpRTyIOpa8bHrypFRkZU95IwWpc3BmNcljc1Oh7BSI2tRVzujOjJh2yycW7ri5ky9k-edbxJn361TgJwZHWL4VIk6GmqeOuv8oky6VF_XSsHSLtk2zm71pvltiLfLc78xSfH-2l-8-0F9BN5ueQTg7ZbnfwEAAP__ysFsnA">