; LLVM IR from smv1999/CompetitiveProgrammingQuestionBank :: Data Structures/Linked Lists/Singly Linked List (detect_loop_in_linkedlist)

; 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.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 noundef zeroext i1 @_Z10detectLoopP4Node(ptr noundef %0) #1 {
  %2 = alloca i1, align 1
  %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
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %7, ptr %5, align 8, !tbaa !5
  store ptr %7, ptr %4, align 8, !tbaa !5
  %8 = load ptr, ptr %4, align 8, !tbaa !5
  %9 = getelementptr inbounds %struct.Node, ptr %8, i32 0, i32 1
  %10 = load ptr, ptr %9, align 8, !tbaa !9
  store ptr %10, ptr %4, align 8, !tbaa !5
  %11 = load ptr, ptr %5, align 8, !tbaa !5
  %12 = getelementptr inbounds %struct.Node, ptr %11, i32 0, i32 1
  %13 = load ptr, ptr %12, align 8, !tbaa !9
  store ptr %13, ptr %5, align 8, !tbaa !5
  %14 = load ptr, ptr %5, align 8, !tbaa !5
  %15 = icmp ne ptr %14, null
  br i1 %15, label %16, label %20

16:                                               ; preds = %1
  %17 = load ptr, ptr %5, align 8, !tbaa !5
  %18 = getelementptr inbounds %struct.Node, ptr %17, i32 0, i32 1
  %19 = load ptr, ptr %18, align 8, !tbaa !9
  store ptr %19, ptr %5, align 8, !tbaa !5
  br label %20

20:                                               ; preds = %16, %1
  br label %21

21:                                               ; preds = %47, %20
  %22 = load ptr, ptr %4, align 8, !tbaa !5
  %23 = icmp ne ptr %22, null
  br i1 %23, label %24, label %27

24:                                               ; preds = %21
  %25 = load ptr, ptr %5, align 8, !tbaa !5
  %26 = icmp ne ptr %25, null
  br label %27

27:                                               ; preds = %24, %21
  %28 = phi i1 [ false, %21 ], [ %26, %24 ]
  br i1 %28, label %29, label %48

29:                                               ; preds = %27
  %30 = load ptr, ptr %4, align 8, !tbaa !5
  %31 = load ptr, ptr %5, align 8, !tbaa !5
  %32 = icmp eq ptr %30, %31
  br i1 %32, label %33, label %34

33:                                               ; preds = %29
  store i1 true, ptr %2, align 1
  store i32 1, ptr %6, align 4
  br label %49

34:                                               ; preds = %29
  %35 = load ptr, ptr %4, align 8, !tbaa !5
  %36 = getelementptr inbounds %struct.Node, ptr %35, i32 0, i32 1
  %37 = load ptr, ptr %36, align 8, !tbaa !9
  store ptr %37, ptr %4, align 8, !tbaa !5
  %38 = load ptr, ptr %5, align 8, !tbaa !5
  %39 = getelementptr inbounds %struct.Node, 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 %5, align 8, !tbaa !5
  %42 = icmp ne ptr %41, null
  br i1 %42, label %43, label %47

43:                                               ; preds = %34
  %44 = load ptr, ptr %5, align 8, !tbaa !5
  %45 = getelementptr inbounds %struct.Node, ptr %44, i32 0, i32 1
  %46 = load ptr, ptr %45, align 8, !tbaa !9
  store ptr %46, ptr %5, align 8, !tbaa !5
  br label %47

47:                                               ; preds = %43, %34
  br label %21, !llvm.loop !12

48:                                               ; preds = %27
  store i1 false, ptr %2, align 1
  store i32 1, ptr %6, align 4
  br label %49

49:                                               ; preds = %48, %33
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  %50 = load i1, ptr %2, align 1
  ret i1 %50
}

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 = { 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 nofree norecurse nosync nounwind willreturn memory(read, inaccessiblemem: none) uwtable
define dso_local noundef zeroext i1 @_Z10detectLoopP4Node(ptr nocapture noundef readonly %0) local_unnamed_addr #0 {
  %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 %._crit_edge, label %4

4:                                                ; preds = %1
  %5 = getelementptr inbounds i8, ptr %3, i64 8
  %6 = load ptr, ptr %5, align 8, !tbaa !5
  %7 = icmp ne ptr %6, null
  %8 = icmp ne ptr %3, %6
  %or.cond.not23 = and i1 %7, %8
  br i1 %or.cond.not23, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %4, %11
  %.125 = phi ptr [ %15, %11 ], [ %6, %4 ]
  %.01424 = phi ptr [ %13, %11 ], [ %3, %4 ]
  %9 = getelementptr inbounds i8, ptr %.125, i64 8
  %10 = load ptr, ptr %9, align 8, !tbaa !5
  %.not20 = icmp eq ptr %10, null
  br i1 %.not20, label %._crit_edge, label %11

11:                                               ; preds = %.lr.ph
  %12 = getelementptr inbounds i8, ptr %.01424, i64 8
  %13 = load ptr, ptr %12, align 8, !tbaa !5
  %14 = getelementptr inbounds i8, ptr %10, i64 8
  %15 = load ptr, ptr %14, align 8, !tbaa !5
  %16 = icmp ne ptr %13, null
  %17 = icmp ne ptr %15, null
  %18 = select i1 %16, i1 %17, i1 false
  %19 = icmp ne ptr %13, %15
  %or.cond.not = select i1 %18, i1 %19, i1 false
  br i1 %or.cond.not, label %.lr.ph, label %._crit_edge, !llvm.loop !11

._crit_edge:                                      ; preds = %11, %.lr.ph, %1, %4
  %.lcssa = phi i1 [ %7, %4 ], [ false, %1 ], [ false, %.lr.ph ], [ %18, %11 ]
  ret i1 %.lcssa
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn 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 = !{!"_ZTS4Node", !7, i64 0, !10, i64 8}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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