; LLVM IR from ImChong/Practice_LeetCode_C :: F02_Programming_Topics/F01_Data_Structure/02_Linked_List/07_DetectCycle/src (DetectCycle)

; 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"

%struct.ListNode = type { i32, ptr }

; Function Attrs: nounwind uwtable
define dso_local ptr @DetectCycle(ptr noundef %0) #0 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %7, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %8, ptr %5, align 8, !tbaa !5
  br label %9

9:                                                ; preds = %46, %1
  %10 = load ptr, ptr %4, align 8, !tbaa !5
  %11 = icmp ne ptr %10, null
  br i1 %11, label %12, label %17

12:                                               ; preds = %9
  %13 = load ptr, ptr %4, align 8, !tbaa !5
  %14 = getelementptr inbounds %struct.ListNode, ptr %13, i32 0, i32 1
  %15 = load ptr, ptr %14, align 8, !tbaa !9
  %16 = icmp ne ptr %15, null
  br label %17

17:                                               ; preds = %12, %9
  %18 = phi i1 [ false, %9 ], [ %16, %12 ]
  br i1 %18, label %19, label %47

19:                                               ; preds = %17
  %20 = load ptr, ptr %5, align 8, !tbaa !5
  %21 = getelementptr inbounds %struct.ListNode, ptr %20, i32 0, i32 1
  %22 = load ptr, ptr %21, align 8, !tbaa !9
  store ptr %22, ptr %5, align 8, !tbaa !5
  %23 = load ptr, ptr %4, align 8, !tbaa !5
  %24 = getelementptr inbounds %struct.ListNode, ptr %23, i32 0, i32 1
  %25 = load ptr, ptr %24, align 8, !tbaa !9
  %26 = getelementptr inbounds %struct.ListNode, ptr %25, i32 0, i32 1
  %27 = load ptr, ptr %26, align 8, !tbaa !9
  store ptr %27, ptr %4, align 8, !tbaa !5
  %28 = load ptr, ptr %5, align 8, !tbaa !5
  %29 = load ptr, ptr %4, align 8, !tbaa !5
  %30 = icmp eq ptr %28, %29
  br i1 %30, label %31, label %46

31:                                               ; preds = %19
  %32 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %32, ptr %5, align 8, !tbaa !5
  br label %33

33:                                               ; preds = %37, %31
  %34 = load ptr, ptr %5, align 8, !tbaa !5
  %35 = load ptr, ptr %4, align 8, !tbaa !5
  %36 = icmp ne ptr %34, %35
  br i1 %36, label %37, label %44

37:                                               ; preds = %33
  %38 = load ptr, ptr %5, align 8, !tbaa !5
  %39 = getelementptr inbounds %struct.ListNode, ptr %38, i32 0, i32 1
  %40 = load ptr, ptr %39, align 8, !tbaa !9
  store ptr %40, ptr %5, align 8, !tbaa !5
  %41 = load ptr, ptr %4, align 8, !tbaa !5
  %42 = getelementptr inbounds %struct.ListNode, ptr %41, i32 0, i32 1
  %43 = load ptr, ptr %42, align 8, !tbaa !9
  store ptr %43, ptr %4, align 8, !tbaa !5
  br label %33, !llvm.loop !12

44:                                               ; preds = %33
  %45 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %45, ptr %2, align 8
  store i32 1, ptr %6, align 4
  br label %48

46:                                               ; preds = %19
  br label %9, !llvm.loop !14

47:                                               ; preds = %17
  store ptr null, ptr %2, align 8
  store i32 1, ptr %6, align 4
  br label %48

48:                                               ; preds = %47, %44
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  %49 = load ptr, ptr %2, align 8
  ret ptr %49
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 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/C++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"ListNode", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}
!14 = distinct !{!14, !13}


; 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: nofree norecurse nosync nounwind memory(read, inaccessiblemem: none) uwtable
define dso_local ptr @DetectCycle(ptr noundef readonly %0) local_unnamed_addr #0 {
  br label %2

2:                                                ; preds = %6, %1
  %.015 = phi ptr [ %0, %1 ], [ %10, %6 ]
  %.0 = phi ptr [ %0, %1 ], [ %8, %6 ]
  %.not = icmp eq ptr %.015, null
  br i1 %.not, label %.critedge, label %3

3:                                                ; preds = %2
  %4 = getelementptr inbounds i8, ptr %.015, i64 8
  %5 = load ptr, ptr %4, align 8, !tbaa !5
  %.not22 = icmp eq ptr %5, null
  br i1 %.not22, label %.critedge, label %6

6:                                                ; preds = %3
  %7 = getelementptr inbounds i8, ptr %.0, i64 8
  %8 = load ptr, ptr %7, align 8, !tbaa !5
  %9 = getelementptr inbounds i8, ptr %5, i64 8
  %10 = load ptr, ptr %9, align 8, !tbaa !5
  %11 = icmp eq ptr %8, %10
  br i1 %11, label %.preheader, label %2, !llvm.loop !11

.preheader:                                       ; preds = %6
  %.not2325 = icmp eq ptr %8, %0
  br i1 %.not2325, label %.critedge, label %.lr.ph

.lr.ph:                                           ; preds = %.preheader, %.lr.ph
  %.127 = phi ptr [ %13, %.lr.ph ], [ %0, %.preheader ]
  %.11626 = phi ptr [ %15, %.lr.ph ], [ %10, %.preheader ]
  %12 = getelementptr inbounds i8, ptr %.127, i64 8
  %13 = load ptr, ptr %12, align 8, !tbaa !5
  %14 = getelementptr inbounds i8, ptr %.11626, i64 8
  %15 = load ptr, ptr %14, align 8, !tbaa !5
  %.not23 = icmp eq ptr %13, %15
  br i1 %.not23, label %.critedge, label %.lr.ph, !llvm.loop !13

.critedge:                                        ; preds = %3, %2, %.lr.ph, %.preheader
  %.017 = phi ptr [ %0, %.preheader ], [ %13, %.lr.ph ], [ null, %2 ], [ null, %3 ]
  ret ptr %.017
}

attributes #0 = { nofree norecurse nosync nounwind memory(read, inaccessiblemem: none) 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" }

!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, !10, i64 8}
!6 = !{!"ListNode", !7, i64 0, !10, i64 8}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}
!13 = distinct !{!13, !12}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass