; LLVM IR from codemistic/Data-Structures-and-Algorithms :: CPP/LINKED LIST/ALGORITHMIC PROBLEMS RELATED TO LINKEDLIST (floydscycle_practice)

; 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: 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
declare dso_local noundef ptr @_Z11floyd_cycleP4node(ptr noundef) #1

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef ptr @_Z13find_startingRP4node(ptr noundef nonnull align 8 dereferenceable(8) %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  %8 = load ptr, ptr %7, align 8, !tbaa !5
  %9 = icmp eq ptr %8, null
  br i1 %9, label %10, label %13

10:                                               ; preds = %1
  %11 = load ptr, ptr %3, align 8, !tbaa !5
  %12 = load ptr, ptr %11, align 8, !tbaa !5
  store ptr %12, ptr %2, align 8
  br label %41

13:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  %15 = load ptr, ptr %14, align 8, !tbaa !5
  %16 = call noundef ptr @_Z11floyd_cycleP4node(ptr noundef %15)
  store ptr %16, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %17 = load ptr, ptr %3, align 8, !tbaa !5
  %18 = load ptr, ptr %17, align 8, !tbaa !5
  store ptr %18, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  %19 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %19, ptr %6, align 8, !tbaa !5
  br label %20

20:                                               ; preds = %39, %13
  %21 = load ptr, ptr %6, align 8, !tbaa !5
  %22 = icmp ne ptr %21, null
  br i1 %22, label %23, label %26

23:                                               ; preds = %20
  %24 = load ptr, ptr %5, align 8, !tbaa !5
  %25 = icmp ne ptr %24, null
  br label %26

26:                                               ; preds = %23, %20
  %27 = phi i1 [ false, %20 ], [ %25, %23 ]
  br i1 %27, label %28, label %40

28:                                               ; preds = %26
  %29 = load ptr, ptr %6, align 8, !tbaa !5
  %30 = getelementptr inbounds %class.node, ptr %29, i32 0, i32 1
  %31 = load ptr, ptr %30, align 8, !tbaa !9
  store ptr %31, ptr %6, align 8, !tbaa !5
  %32 = load ptr, ptr %5, 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 %5, align 8, !tbaa !5
  %35 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %35, ptr %6, align 8, !tbaa !5
  %36 = icmp ne ptr %35, null
  br i1 %36, label %37, label %39

37:                                               ; preds = %28
  %38 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %38, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  br label %41

39:                                               ; preds = %28
  br label %20, !llvm.loop !12

40:                                               ; preds = %26
  unreachable

41:                                               ; preds = %37, %10
  %42 = load ptr, ptr %2, align 8
  ret ptr %42
}

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 nounwind uwtable
declare dso_local noundef ptr @_Z11floyd_cycleP4node(ptr noundef) local_unnamed_addr #0

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef ptr @_Z13find_startingRP4node(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 %10, label %4

4:                                                ; preds = %1
  %5 = tail call noundef ptr @_Z11floyd_cycleP4node(ptr noundef nonnull %2)
  %6 = load ptr, ptr %0, align 8, !tbaa !5, !nonnull !9, !noundef !9
  %7 = icmp ne ptr %5, null
  tail call void @llvm.assume(i1 %7)
  %8 = getelementptr inbounds i8, ptr %6, i64 8
  %9 = load ptr, ptr %8, align 8, !tbaa !10, !nonnull !9, !noundef !9
  br label %10

10:                                               ; preds = %1, %4
  %.013 = phi ptr [ %9, %4 ], [ null, %1 ]
  ret ptr %.013
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write)
declare void @llvm.assume(i1 noundef) #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 = { nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) }

!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 = !{!11, !6, i64 8}
!11 = !{!"_ZTS4node", !12, i64 0, !6, i64 8}
!12 = !{!"int", !7, i64 0}


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