; LLVM IR from JessonYue/LeetCodeLearning :: Array/wuchao/linkedlist/6-25 寻找环形链表的环形入口 (FindLinkedListCycleEntryNode)

; 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 = %32, %1
  %10 = load ptr, ptr %5, align 8, !tbaa !5
  %11 = icmp ne ptr %10, null
  br i1 %11, label %12, label %17

12:                                               ; preds = %9
  %13 = load ptr, ptr %5, 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 %33

19:                                               ; preds = %17
  %20 = load ptr, ptr %4, 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 %4, align 8, !tbaa !5
  %23 = load ptr, ptr %5, 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 %5, align 8, !tbaa !5
  %28 = load ptr, ptr %4, align 8, !tbaa !5
  %29 = load ptr, ptr %5, align 8, !tbaa !5
  %30 = icmp eq ptr %28, %29
  br i1 %30, label %31, label %32

31:                                               ; preds = %19
  br label %33

32:                                               ; preds = %19
  br label %9, !llvm.loop !12

33:                                               ; preds = %31, %17
  %34 = load ptr, ptr %5, align 8, !tbaa !5
  %35 = icmp eq ptr %34, null
  br i1 %35, label %41, label %36

36:                                               ; preds = %33
  %37 = load ptr, ptr %5, align 8, !tbaa !5
  %38 = getelementptr inbounds %struct.ListNode, ptr %37, i32 0, i32 1
  %39 = load ptr, ptr %38, align 8, !tbaa !9
  %40 = icmp eq ptr %39, null
  br i1 %40, label %41, label %42

41:                                               ; preds = %36, %33
  store ptr null, ptr %2, align 8
  store i32 1, ptr %6, align 4
  br label %57

42:                                               ; preds = %36
  %43 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %43, ptr %5, align 8, !tbaa !5
  br label %44

44:                                               ; preds = %48, %42
  %45 = load ptr, ptr %4, align 8, !tbaa !5
  %46 = load ptr, ptr %5, align 8, !tbaa !5
  %47 = icmp ne ptr %45, %46
  br i1 %47, label %48, label %55

48:                                               ; preds = %44
  %49 = load ptr, ptr %4, align 8, !tbaa !5
  %50 = getelementptr inbounds %struct.ListNode, ptr %49, i32 0, i32 1
  %51 = load ptr, ptr %50, align 8, !tbaa !9
  store ptr %51, ptr %4, align 8, !tbaa !5
  %52 = load ptr, ptr %5, align 8, !tbaa !5
  %53 = getelementptr inbounds %struct.ListNode, ptr %52, i32 0, i32 1
  %54 = load ptr, ptr %53, align 8, !tbaa !9
  store ptr %54, ptr %5, align 8, !tbaa !5
  br label %44, !llvm.loop !14

55:                                               ; preds = %44
  %56 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %56, ptr %2, align 8
  store i32 1, ptr %6, align 4
  br label %57

57:                                               ; preds = %55, %41
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  %58 = load ptr, ptr %2, align 8
  ret ptr %58
}

; 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 {
  %.old1.not = icmp eq ptr %0, null
  br i1 %.old1.not, label %.critedge.thread, label %.preheader35

.preheader35:                                     ; preds = %1, %4
  %.018 = phi ptr [ %6, %4 ], [ %0, %1 ]
  %.0 = phi ptr [ %8, %4 ], [ %0, %1 ]
  %2 = getelementptr inbounds i8, ptr %.0, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !5
  %.not = icmp eq ptr %3, null
  br i1 %.not, label %.critedge.thread, label %4

4:                                                ; preds = %.preheader35
  %5 = getelementptr inbounds i8, ptr %.018, i64 8
  %6 = load ptr, ptr %5, align 8, !tbaa !5
  %7 = getelementptr inbounds i8, ptr %3, i64 8
  %8 = load ptr, ptr %7, align 8, !tbaa !5
  %9 = icmp ne ptr %6, %8
  %10 = icmp ne ptr %8, null
  %or.cond = and i1 %9, %10
  br i1 %or.cond, label %.preheader35, label %.critedge, !llvm.loop !11

.critedge:                                        ; preds = %4
  %11 = icmp eq ptr %8, null
  br i1 %11, label %.critedge.thread, label %.critedge.thread30

.critedge.thread30:                               ; preds = %.critedge
  %.phi.trans.insert = getelementptr inbounds i8, ptr %8, i64 8
  %.pre = load ptr, ptr %.phi.trans.insert, align 8, !tbaa !5
  %12 = icmp eq ptr %.pre, null
  br i1 %12, label %.critedge.thread, label %.preheader

.preheader:                                       ; preds = %.critedge.thread30
  %.not2739 = icmp eq ptr %6, %0
  br i1 %.not2739, label %.critedge.thread, label %.lr.ph

.lr.ph:                                           ; preds = %.preheader, %.lr.ph
  %.241 = phi ptr [ %16, %.lr.ph ], [ %0, %.preheader ]
  %.22040 = phi ptr [ %14, %.lr.ph ], [ %6, %.preheader ]
  %13 = getelementptr inbounds i8, ptr %.22040, i64 8
  %14 = load ptr, ptr %13, align 8, !tbaa !5
  %15 = getelementptr inbounds i8, ptr %.241, i64 8
  %16 = load ptr, ptr %15, align 8, !tbaa !5
  %.not27 = icmp eq ptr %14, %16
  br i1 %.not27, label %.critedge.thread, label %.lr.ph, !llvm.loop !13

.critedge.thread:                                 ; preds = %.preheader35, %.lr.ph, %.preheader, %1, %.critedge, %.critedge.thread30
  %.021 = phi ptr [ null, %.critedge.thread30 ], [ null, %.critedge ], [ null, %1 ], [ %6, %.preheader ], [ %14, %.lr.ph ], [ null, %.preheader35 ]
  ret ptr %.021
}

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: BDCEPass,CorrelatedValuePropagationPass,EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass