; LLVM IR from smv1999/CompetitiveProgrammingQuestionBank :: Data Structures/Linked Lists/Doubly Linked List (delete_at_begin)

; 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.dll_node = type { ptr, 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 @_Z15delete_at_beginRP8dll_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 %8, label %9

8:                                                ; preds = %1
  br label %42

9:                                                ; preds = %1
  %10 = load ptr, ptr %2, align 8, !tbaa !5
  %11 = load ptr, ptr %10, align 8, !tbaa !5
  %12 = getelementptr inbounds %class.dll_node, ptr %11, i32 0, i32 2
  %13 = load ptr, ptr %12, align 8, !tbaa !9
  %14 = icmp eq ptr %13, null
  br i1 %14, label %15, label %27

15:                                               ; preds = %9
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #3
  %16 = load ptr, ptr %2, align 8, !tbaa !5
  %17 = load ptr, ptr %16, align 8, !tbaa !5
  store ptr %17, ptr %3, align 8, !tbaa !5
  %18 = load ptr, ptr %2, align 8, !tbaa !5
  %19 = load ptr, ptr %18, align 8, !tbaa !5
  %20 = getelementptr inbounds %class.dll_node, ptr %19, i32 0, i32 2
  %21 = load ptr, ptr %20, align 8, !tbaa !9
  %22 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %21, ptr %22, align 8, !tbaa !5
  %23 = load ptr, ptr %3, align 8, !tbaa !5
  %24 = icmp eq ptr %23, null
  br i1 %24, label %26, label %25

25:                                               ; preds = %15
  call void @_ZdlPvm(ptr noundef %23, i64 noundef 24) #4
  br label %26

26:                                               ; preds = %25, %15
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #3
  br label %42

27:                                               ; preds = %9
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  %28 = load ptr, ptr %2, align 8, !tbaa !5
  %29 = load ptr, ptr %28, align 8, !tbaa !5
  store ptr %29, ptr %4, align 8, !tbaa !5
  %30 = load ptr, ptr %2, align 8, !tbaa !5
  %31 = load ptr, ptr %30, align 8, !tbaa !5
  %32 = getelementptr inbounds %class.dll_node, ptr %31, i32 0, i32 2
  %33 = load ptr, ptr %32, align 8, !tbaa !9
  %34 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %33, ptr %34, align 8, !tbaa !5
  %35 = load ptr, ptr %2, align 8, !tbaa !5
  %36 = load ptr, ptr %35, align 8, !tbaa !5
  %37 = getelementptr inbounds %class.dll_node, ptr %36, i32 0, i32 0
  store ptr null, ptr %37, align 8, !tbaa !12
  %38 = load ptr, ptr %4, align 8, !tbaa !5
  %39 = icmp eq ptr %38, null
  br i1 %39, label %41, label %40

40:                                               ; preds = %27
  call void @_ZdlPvm(ptr noundef %38, i64 noundef 24) #4
  br label %41

41:                                               ; preds = %40, %27
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  br label %42

42:                                               ; preds = %41, %26, %8
  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 = { nounwind }
attributes #4 = { 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 16}
!10 = !{!"_ZTS8dll_node", !6, i64 0, !11, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 0}


; 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 @_Z15delete_at_beginRP8dll_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 %9, label %4

4:                                                ; preds = %1
  %5 = getelementptr inbounds i8, ptr %2, i64 16
  %6 = load ptr, ptr %5, align 8, !tbaa !9
  %7 = icmp eq ptr %6, null
  br i1 %7, label %.sink.split, label %8

8:                                                ; preds = %4
  store ptr %6, ptr %0, align 8, !tbaa !5
  br label %.sink.split

.sink.split:                                      ; preds = %4, %8
  %.sink = phi ptr [ %6, %8 ], [ %0, %4 ]
  store ptr null, ptr %.sink, align 8, !tbaa !5
  tail call void @_ZdlPvm(ptr noundef nonnull %2, i64 noundef 24) #2
  br label %9

9:                                                ; preds = %.sink.split, %1
  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 16}
!10 = !{!"_ZTS8dll_node", !6, i64 0, !11, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}


; Effective O3 passes: CorrelatedValuePropagationPass,EarlyCSEPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass