; LLVM IR from smv1999/CompetitiveProgrammingQuestionBank :: Data Structures/Linked Lists/Circular Linked Lists (delete_at_end)

; Unoptimized IR (clang -disable-llvm-passes):
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

%class.cll_node = type { i32, ptr }

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: mustprogress nounwind uwtable
define dso_local void @_Z13delete_at_endRP8cll_node(ptr noundef nonnull align 8 dereferenceable(8) %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  %5 = load ptr, ptr %2, align 8, !tbaa !5
  %6 = load ptr, ptr %5, align 8, !tbaa !5
  %7 = icmp eq ptr %6, null
  br i1 %7, label %16, label %8

8:                                                ; preds = %1
  %9 = load ptr, ptr %2, align 8, !tbaa !5
  %10 = load ptr, ptr %9, align 8, !tbaa !5
  %11 = getelementptr inbounds %class.cll_node, ptr %10, i32 0, i32 1
  %12 = load ptr, ptr %11, align 8, !tbaa !9
  %13 = load ptr, ptr %2, align 8, !tbaa !5
  %14 = load ptr, ptr %13, align 8, !tbaa !5
  %15 = icmp eq ptr %12, %14
  br i1 %15, label %16, label %23

16:                                               ; preds = %8, %1
  %17 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr null, ptr %17, align 8, !tbaa !5
  %18 = load ptr, ptr %2, align 8, !tbaa !5
  %19 = load ptr, ptr %18, align 8, !tbaa !5
  %20 = icmp eq ptr %19, null
  br i1 %20, label %22, label %21

21:                                               ; preds = %16
  call void @_ZdlPvm(ptr noundef %19, i64 noundef 16) #3
  br label %22

22:                                               ; preds = %21, %16
  br label %51

23:                                               ; preds = %8
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #4
  %24 = load ptr, ptr %2, align 8, !tbaa !5
  %25 = load ptr, ptr %24, align 8, !tbaa !5
  store ptr %25, ptr %3, align 8, !tbaa !5
  br label %26

26:                                               ; preds = %35, %23
  %27 = load ptr, ptr %3, align 8, !tbaa !5
  %28 = getelementptr inbounds %class.cll_node, ptr %27, i32 0, i32 1
  %29 = load ptr, ptr %28, align 8, !tbaa !9
  %30 = getelementptr inbounds %class.cll_node, ptr %29, i32 0, i32 1
  %31 = load ptr, ptr %30, align 8, !tbaa !9
  %32 = load ptr, ptr %2, align 8, !tbaa !5
  %33 = load ptr, ptr %32, align 8, !tbaa !5
  %34 = icmp ne ptr %31, %33
  br i1 %34, label %35, label %39

35:                                               ; preds = %26
  %36 = load ptr, ptr %3, align 8, !tbaa !5
  %37 = getelementptr inbounds %class.cll_node, ptr %36, i32 0, i32 1
  %38 = load ptr, ptr %37, align 8, !tbaa !9
  store ptr %38, ptr %3, align 8, !tbaa !5
  br label %26, !llvm.loop !12

39:                                               ; preds = %26
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #4
  %40 = load ptr, ptr %3, align 8, !tbaa !5
  %41 = getelementptr inbounds %class.cll_node, ptr %40, i32 0, i32 1
  %42 = load ptr, ptr %41, align 8, !tbaa !9
  store ptr %42, ptr %4, align 8, !tbaa !5
  %43 = load ptr, ptr %2, align 8, !tbaa !5
  %44 = load ptr, ptr %43, align 8, !tbaa !5
  %45 = load ptr, ptr %3, align 8, !tbaa !5
  %46 = getelementptr inbounds %class.cll_node, ptr %45, i32 0, i32 1
  store ptr %44, ptr %46, align 8, !tbaa !9
  %47 = load ptr, ptr %4, align 8, !tbaa !5
  %48 = icmp eq ptr %47, null
  br i1 %48, label %50, label %49

49:                                               ; preds = %39
  call void @_ZdlPvm(ptr noundef %47, i64 noundef 16) #3
  br label %50

50:                                               ; preds = %49, %39
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #4
  br label %51

51:                                               ; preds = %50, %22
  ret void
}

; Function Attrs: nobuiltin nounwind
declare void @_ZdlPvm(ptr noundef, i64 noundef) #2

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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 #2 = { nobuiltin nounwind "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 #3 = { builtin nounwind }
attributes #4 = { 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 19.1.0 (git@github.com:llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)"}
!5 = !{!6, !6, i64 0}
!6 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS8cll_node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


; Optimized IR (opt -passes='default<O3>'):
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: mustprogress nounwind uwtable
define dso_local void @_Z13delete_at_endRP8cll_node(ptr nocapture noundef nonnull align 8 dereferenceable(8) %0) local_unnamed_addr #0 {
  %2 = load ptr, ptr %0, align 8, !tbaa !5
  %3 = icmp eq ptr %2, null
  br i1 %3, label %8, label %4

4:                                                ; preds = %1
  %5 = getelementptr inbounds i8, ptr %2, i64 8
  %6 = load ptr, ptr %5, align 8, !tbaa !9
  %7 = icmp eq ptr %6, %2
  br i1 %7, label %8, label %.preheader

8:                                                ; preds = %4, %1
  store ptr null, ptr %0, align 8, !tbaa !5
  br label %14

.preheader:                                       ; preds = %4, %.preheader
  %9 = phi ptr [ %11, %.preheader ], [ %6, %4 ]
  %.0 = phi ptr [ %9, %.preheader ], [ %2, %4 ]
  %10 = getelementptr inbounds i8, ptr %9, i64 8
  %11 = load ptr, ptr %10, align 8, !tbaa !9
  %.not = icmp eq ptr %11, %2
  br i1 %.not, label %12, label %.preheader, !llvm.loop !12

12:                                               ; preds = %.preheader
  %13 = getelementptr inbounds i8, ptr %.0, i64 8
  store ptr %2, ptr %13, align 8, !tbaa !9
  tail call void @_ZdlPvm(ptr noundef nonnull %9, i64 noundef 16) #2
  br label %14

14:                                               ; preds = %12, %8
  ret void
}

; Function Attrs: nobuiltin nounwind
declare void @_ZdlPvm(ptr noundef, i64 noundef) local_unnamed_addr #1

attributes #0 = { mustprogress 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 = { nobuiltin nounwind "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 = { builtin 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 19.1.0 (git@github.com:llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)"}
!5 = !{!6, !6, i64 0}
!6 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS8cll_node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: CorrelatedValuePropagationPass,EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass