; LLVM IR from devparthgarg/Data-Structures-and-Algorithms :: 11. Linked List/21 Delete at Head Circular LL (21 Delete At Head Circular LL)

; 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.Node = type { i32, ptr }

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef ptr @_Z12deleteAtHeadRP4Node(ptr noundef nonnull align 8 dereferenceable(8) %0) #0 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %5 = load ptr, ptr %3, 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
  store ptr null, ptr %2, align 8
  br label %50

9:                                                ; preds = %1
  %10 = load ptr, ptr %3, align 8, !tbaa !5
  %11 = load ptr, ptr %10, align 8, !tbaa !5
  %12 = getelementptr inbounds %class.Node, ptr %11, i32 0, i32 1
  %13 = load ptr, ptr %12, align 8, !tbaa !9
  %14 = icmp eq ptr %13, null
  br i1 %14, label %15, label %21

15:                                               ; preds = %9
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  %17 = load ptr, ptr %16, align 8, !tbaa !5
  %18 = icmp eq ptr %17, null
  br i1 %18, label %20, label %19

19:                                               ; preds = %15
  call void @_ZdlPvm(ptr noundef %17, i64 noundef 16) #3
  br label %20

20:                                               ; preds = %19, %15
  store ptr null, ptr %2, align 8
  br label %50

21:                                               ; preds = %9
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #4
  %22 = load ptr, ptr %3, align 8, !tbaa !5
  %23 = load ptr, ptr %22, align 8, !tbaa !5
  store ptr %23, ptr %4, align 8, !tbaa !5
  br label %24

24:                                               ; preds = %31, %21
  %25 = load ptr, ptr %4, align 8, !tbaa !5
  %26 = getelementptr inbounds %class.Node, ptr %25, i32 0, i32 1
  %27 = load ptr, ptr %26, align 8, !tbaa !9
  %28 = load ptr, ptr %3, align 8, !tbaa !5
  %29 = load ptr, ptr %28, align 8, !tbaa !5
  %30 = icmp ne ptr %27, %29
  br i1 %30, label %31, label %35

31:                                               ; preds = %24
  %32 = load ptr, ptr %4, align 8, !tbaa !5
  %33 = getelementptr inbounds %class.Node, ptr %32, i32 0, i32 1
  %34 = load ptr, ptr %33, align 8, !tbaa !9
  store ptr %34, ptr %4, align 8, !tbaa !5
  br label %24, !llvm.loop !12

35:                                               ; preds = %24
  %36 = load ptr, ptr %3, align 8, !tbaa !5
  %37 = load ptr, ptr %36, align 8, !tbaa !5
  %38 = getelementptr inbounds %class.Node, ptr %37, i32 0, i32 1
  %39 = load ptr, ptr %38, align 8, !tbaa !9
  %40 = load ptr, ptr %4, align 8, !tbaa !5
  %41 = getelementptr inbounds %class.Node, ptr %40, i32 0, i32 1
  store ptr %39, ptr %41, align 8, !tbaa !9
  %42 = load ptr, ptr %3, align 8, !tbaa !5
  %43 = load ptr, ptr %42, align 8, !tbaa !5
  %44 = icmp eq ptr %43, null
  br i1 %44, label %46, label %45

45:                                               ; preds = %35
  call void @_ZdlPvm(ptr noundef %43, i64 noundef 16) #3
  br label %46

46:                                               ; preds = %45, %35
  %47 = load ptr, ptr %4, align 8, !tbaa !5
  %48 = getelementptr inbounds %class.Node, ptr %47, i32 0, i32 1
  %49 = load ptr, ptr %48, align 8, !tbaa !9
  store ptr %49, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #4
  br label %50

50:                                               ; preds = %46, %20, %8
  %51 = load ptr, ptr %2, align 8
  ret ptr %51
}

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

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #2

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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 = !{!"_ZTS4Node", !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 noundef ptr @_Z12deleteAtHeadRP4Node(ptr nocapture noundef nonnull readonly 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 %16, 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, null
  br i1 %7, label %8, label %.preheader

8:                                                ; preds = %4
  tail call void @_ZdlPvm(ptr noundef nonnull %2, i64 noundef 16) #2
  br label %16

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

11:                                               ; preds = %.preheader
  %12 = getelementptr inbounds i8, ptr %.0, i64 8
  store ptr %6, ptr %12, align 8, !tbaa !9
  %13 = load ptr, ptr %0, align 8, !tbaa !5
  %14 = icmp eq ptr %13, null
  br i1 %14, label %16, label %15

15:                                               ; preds = %11
  tail call void @_ZdlPvm(ptr noundef nonnull %13, i64 noundef 16) #2
  %.pre = load ptr, ptr %12, align 8, !tbaa !9
  br label %16

16:                                               ; preds = %11, %15, %1, %8
  %.012 = phi ptr [ null, %8 ], [ null, %1 ], [ %.pre, %15 ], [ %6, %11 ]
  ret ptr %.012
}

; 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 = !{!"_ZTS4Node", !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