<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/64610>64610</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Dead Code Elimination Regression at -O3 (trunk vs. llvmorg-16.0.6)
        </td>
    </tr>

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

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

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

<pre>
    ```c
static short b, c;
void foo(void);
static char(a)(char e, char f) { return e - f; }
static short(d)(short e) { return e; }
int main() {
  int g = a((7 > 2 ^ b) < b, 71);
  if (!(g >= -71 && g <= -71))
    foo();
  short h = d(74);
  b = h;
  c = d(0);
  a(0, c);
}
```

`clang-460868611118 (trunk) -O3` cannot eliminate the call to foo but `clang-llvmorg-16.0.6 -O3` can.

-----------------------------------------------------------------------

`clang-46086861111849bcb6e20de827750862d5345cbd -O3 case.c -S -emit-llvm -o case.ll`
<details ><summary>Emitted IR</summary><p>

```ll
; ModuleID = 'case.c'
source_filename = "case.c"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

@b = internal unnamed_addr global i1 false, align 2

; Function Attrs: nounwind uwtable
define dso_local i32 @main() local_unnamed_addr #0 {
  %1 = load i1, ptr @b, align 2
  %2 = select i1 %1, i32 74, i32 0
  %3 = or i32 %2, 1
  %4 = icmp ugt i32 %3, %2
  br i1 %4, label %6, label %5

5: ; preds = %0
  tail call void @foo() #2
  br label %6

6: ; preds = %0, %5
  store i1 true, ptr @b, align 2
  ret i32 0
}

declare void @foo() local_unnamed_addr #1

attributes #0 = { nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #2 = { nounwind }

!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"clang version 18.0.0 (git@github.com:llvm/llvm-project.git 46086861111849bcb6e20de827750862d5345cbd)"}
```


</p></details>

-----------------------------------------------------------------------

`clang-af2ed9f794c422923414d162dd1f48d986e2d6e3 -O3 case.c -S -emit-llvm -o case.ll`
<details ><summary>Emitted IR</summary><p>

```ll
; ModuleID = 'case.c'
source_filename = "case.c"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

@b = internal unnamed_addr global i1 false, align 2

; Function Attrs: nounwind uwtable
define dso_local i32 @main() local_unnamed_addr #0 {
  store i1 true, ptr @b, align 2
  ret i32 0
}

attributes #0 = { nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }

!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"clang version 16.0.6 (git@github.com:llvm/llvm-project.git 7cbf1a2591520c2491aa35339f227775f4d3adf6)"}
```


</p></details>

-----------------------------------------------------------------------

Bisects to 726f8ecac23bf04b60f9f079ee922b8a7a30457f
Committed by: @goldsteinn

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsWO9u5LgNfxrNF8EDifLfD_NhM0mABVq0uH2AQJZoj25leSDLSbZPX0j2TDzJbbdF74D2sEEwpkT-KIqkRNpymkzvEA-kuCPF_U7O4TT6w5dndL_KL-qE3qPftaP-diAlW_4VYfeEfZqCDEbR6TT6QFsCR6qIuFt4z6PRtBtHAnUkCTRX1gpTJ-kJ1DKyoI4jiklHpDoCDSXVHfUYZu8o0ox2RNxRUt1_XJxArRc1iy34Hn2DNC7QQRpHoF7llnlKI6enRNxTmZh1RYl4oEBJ8RA32FAijstOK77dEqWmownCCdRRxUPUklWcEigJlEntcZ1LpjYXJF3ddKtv2cgpGaOjJfktv02c02ZGXWXZrahcpmJ0NvNXd1yjug4vk8pK12d5yeqyLjnnvI47DH52X6Mnsr8JUjKqpHNjoGjNYJwMSMMJqZLW0jDGjdF2DvSqzdrnYfR9xss925cbHfvt4tnv8_fD_eRNq9oSgWmsoaoKVpegC5EXqtXRNqrkhHtFsy80w8GEZD7NxmXe2jefiaPGII2dlsgfp3kYpP9GxMPDYEJATT__EuMPj28cIo7n-Li1cvm39qL4jv511LPFz_cpvASqxSgC1XoOxtkrfOqMRScHXKXgIgWLVJC-x0C1DNLKb2OMySKH2UDEJ8zOUDEiPglIP3HIb4eRKvP0k5kL0dURxKHOXB2J8oIp8-wLjzl9u37w5myvNr7W5VOZZ7P76sYXl1nj5tesd_MVtf7mbMl24wJ6Jy2dXdyqfpJae9rbsZWWGk47aad0hUhrekdvlYg7-jg7Fczo6KcQ_ETEJ-rG2b0Yp-n8EmRrcZHV2BmHVE_jkx1V1C2AkpxtLo00_3RjBwHBtpcJgYIns-0oNTU8GnYOPipqPxiZxCGJT2hRhbifqCFKxuXj-V8otkGIhBj9YiEUEIX4RiBfHKeGM537cBETUSyJX24Tv66XVrGyRRtH5c2o2PqziO6LTj171NMa0eJqWzwMyzWQCgHJ2fWSi47aLrxZbaO__I7-xfDiek2G0WO0PfgZf-Bhj2HrwLcLcA26stLjb9j727HmW7AMwZt2DjitaRDNre4-5FfM-sG4zGIvbfaMKow-ezE6nGLOi3sCwAjEGIEbs-Dl-Wxcnw1yI7DsNMlMQaqv2dmPYdHUzl2HPpvMP_AqXq-yywnM1Hm-sl7rMivzW36HMswep6sQgTs1jM8EjpF6rReie538Qg3D60JM6ewtBCzUa11dtM8Ob9bu0aE3KrEvgbj1Ir968ac3QMDHnHqXwAR4rE_7IdWLfWdlfzk3PF5LwNfTw_n6hPUp3jStOoxGF27B-cfl2EYiHqyLXgLwEru4p4vr15sr367D34HrN_DfPx_pX_AZ7QYLWyy8w1Zb7MO_xorvYy9F4DvI_NYhscjGloI-o59iVeH1nu1ZbJJ6E0jOehNOc7tXY6yw0a0EHuMjpuivqMK-N4H-u_1I6hnhB03bpRkh8HheOgwCj2tn8q7V-CN7LNkB6qarmlzlAA2InOeal6A17_JaN3WJoEsUP3usnz3Wf9dj_X7l_09ewf_QSvWz_vxv1J_lpfo_qz-VajsuoWh4AUxB3nApRSFE0wFUVVV0uRZSd-X_Qf25MxOqMNEw0grKrkYlFYi2Y3lbsq7pWNUgNgBtLSspWF5U3QI8jsNaQdpv6bUjZ_1o9RTQOLeI7PRB6EY0cocHXja8yoEJvjsdSglYqZoBqq5oOyUa1rISuwJapZTSO3MABoLVnLM6YvYMmFJ52ZQ1QxBNRXKGgzR2nzJ_9P3OTNOMhzIvOdult6MpfZwDcPhCEzOGorjf-UOKZzv3E8mZNVOY3rQEEywe7lFqehw10of1E01MlV-w9zilrJEhleHLpx36PO3p7WcaAs1u9vZwCuEcb3QCjwQeN9m1pNW77CLwmEydCDymrfwzAAD__3i4cAI">