<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/61549>61549</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            AArch64 miscompile
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            backend:AArch64,
            llvm:codegen,
            miscompilation
      </td>
    </tr>

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

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

<pre>
    here's a function:
```llvm
define i35 @f(i35 %0) {
  %2 = srem i35 1, %0
  %3 = call i35 @llvm.ctlz.i35(i35 %2, i1 false)
  %4 = lshr i35 %3, 5
  ret i35 %4
}

declare i35 @llvm.ctlz.i35(i35, i1 immarg) #0
```
when passed `8` as an argument, it should return `1` because:
```
%2 = 1
%3 = 34
%4 = 1
```
however, when compiled to AArch64 by latest llc we get:
```
_f:
        mov     w8, #1 
        sbfx    x9, x0, #0, #35
        sdiv    x10, x8, x9
        msub    x8, x10, x9, x8
        eor     x0, x8, #0x1
        ret
```
and this returns `0` for the same input, verified using this driver:
```
unsigned long f(unsigned long);

#include <stdio.h>

int main(void) {
  unsigned long res = f(8UL);
  printf("%lu\n", res);
}
```

cc @nunoplopes 
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJx8lEuP6yYUgH8N2RzdCIPt2AsvMjPNqtuuKwzHNi2GCHAmt7--AjuvaedKUQycj_PgPEQIerSIHaneSPWxE0ucnO88jjj5Xe_Uz25Cj4QdAggYFiujdpbwI6EfhB5JTdefMZd5PVI4aIugeQWkpANhTV6yihLWAjm8rRikIwaEf0DwOGe-IOx9JR8Iz4gUxtxUJlN7Gc0_e82rh3qWLusCBmECEtY-6SizDhMmDxvME1zdEI_xJii3uA4f22KLSRrh8RcebMb1PAs_5kAZp1_eaN1-TmjhLEJABaSmDakpiADCgvDjMqONWVeEMLnFqOTc4m1Ci4T2KMUS8L8Z2La3Ry3u-_UFeXk_KF-A1_uT-8QL-uRCdlS6-awNKogOjkcvp7qE_icYETFEMEbCJ8KI8Tt__hweEtrO7kJo-9mseeYF3CWhH66Ettc2ia50A25fXj1ApZOOa5Fl16zq2j4shKUHgJtgo9qNvVHofNLxpCIZuxZ3wGP833CEVRAnHbashJSWJIXBeYgTQhAzgrbnJWfxgl4PGhUsQdtxvam8Tg_8zXstNvejAuPsCKl7Xk5SXfO359IkjGsrzaIQCH8PUWm3nwj_7ZnRNsIstCWsuTitvvThq0mPIZdHMt388fuzQYCz1zYmCWGMsMospHq3ef2eLr54d--gLwWa_6VMfWQX687GnTHATnVctbwVO-yK-tByVpdNs5u6gtW0YWXRH8paNEq2om2ralCylEVVNsNOd4wyTjmjRcXLstlT1ouCHuiBHRrV1C0pKc5Cm31uW-fHnQ5hwa4uqrLdGdGjCXn8MdYL-TdaRfhxq_U1NsJYnm_8KJ3CEe39eNZh7RCRxyJjaYb6LtE_-mUMaVjoEMPDdtTRYHdrpft93C3edFOM55BKg50IO406Tku_l24m7JQdWD8_zt79hTISdsqRBMJOOZh_AwAA__-LRpWw">