<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/55627>55627</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            miscompile of non-canonical add+icmp by arm64 backend
        </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>
    ```llvm
define i1 @f() {
  %1 = add i8 0, 159
  %2 = icmp ugt i8 243, %1
  ret i1 %2
}
```
this clearly needs to compile to something emitting true (a few other backends I tried do this) but using top of tree this is what we get from the arm64 backend:
```console
regehr@john-home:~$ llc --march=aarch64 foo.ll -o -
        .text
        .file   "foo.ll"
        .globl  f                               // -- Begin function f
        .p2align        2
        .type   f,@function
f:                                      // @f
        .cfi_startproc
// %bb.0:
        mov     w0, wzr
        ret
.Lfunc_end0:
        .size   f, .Lfunc_end0-f
        .cfi_endproc
                                        // -- End function
        .section        ".note.GNU-stack","",@progbits
regehr@john-home:~$ 
```
cc @ornata @nunoplopes @ryan-berger @nbushehri @zhengyang92 @aqjune @Hatsunespica
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJyNVE2PnDgQ_TX0pQSi3UDDgUNPZiZZabW3PUfGFOCJsYlt0tvz67dsuqdnotUmCEFVvXJ9PLvcmf7SJlW-vUr9mJP8MclPPQ5SI8g9JEU-JKxOWAPJ8WFDARJWEnR4BN73IGvIE_YJ9mXzDmcRl2JeYB19cGLFIbiFtTc_iz4mIffNlBwfr8KtqE31k3QgFHKrLqARewfegDDzIhUG0ZkZyUmPgLP0Pgjerkihaw4DnsH4CS10XHxDTav_IFhiD72BEDv0160eVhdXmgXMQB6IEQV6zxP3cEYYqeTBmpkABG7nqrgFTQ6nn2oXRjujcLNaHHGyxOeLmXQ6Ub1hwfEpYQUoJSBNZ27FRKzx8Ke4gzGZUpAaSK-B8ybz-I-_a4MM4ZuEsc2ZhDs4KtMpEgb4_ydhz_RSAfCAo9QwrFp4aUi4x1oYV3LUJL5L4C9LyE4H5FM4J9dlGz5Qd7_I-zF9PGlvocUgvzrPrV-sEVfz1Y-VXZfld7bzZjY_6HuOp_D8at_sdLw2OfszFPeVNunDuszJ11sD8M4n_akQst3L-L2m3rP6pHv4SE7MjVdD2L1MG4_Z57_-Tqlp8S1sI3Eavmwjl_KPnfTu12fpP-dHiMCvsZp7HiS9arMos6ALmr1wnXZoR5qQAHarmyi-DMrrhHokfGxYUPn3l5VuBpK-cO9IdIsUfNe3h745NHznpVfYztLdZpPmSBudCk5f8lThykjYQ7wYusvHCdqtVrWT94sL7UT-RumntcsoGinxgtp-KRHyQgySKp1bkSb4uSwrdtxNbd6XPdaDYGXd10essCvrgxiqumrEseqrneIdKtcm5QPxe5_e0ynO3cY57R-L-Q4nYXriW9_tb-3xuINkLx93smU5Y3nJ9vumOJQsK459UfCK1fsy50XNiTOcuVRZCJsZO-5sG1vp1tERqKTz7g5y52jgEGOZFJ-vfjK23bZ-F5tuY8f_AvPapog">