; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 10. Linked List/findNthnode-from-endLL.ll (Z16printNthFromLastP4Nodei)

; 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.std::basic_ostream" = type { ptr, %"class.std::basic_ios" }
%"class.std::basic_ios" = type { %"class.std::ios_base", ptr, i8, i8, ptr, ptr, ptr, ptr }
%"class.std::ios_base" = type { ptr, i64, i64, i32, i32, i32, ptr, %"struct.std::ios_base::_Words", [8 x %"struct.std::ios_base::_Words"], i32, ptr, %"class.std::locale" }
%"struct.std::ios_base::_Words" = type { ptr, i64 }
%"class.std::locale" = type { ptr }
%struct.Node = type { i32, ptr }

@_ZSt4cout = external global %"class.std::basic_ostream", align 8

; Function Attrs: mustprogress uwtable
define dso_local void @_Z16printNthFromLastP4Nodei(ptr noundef %0, i32 noundef %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca ptr, align 8
  %8 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  store i32 0, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #3
  call void @llvm.lifetime.start.p0(i64 8, ptr %7) #3
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %9, ptr %7, align 8, !tbaa !5
  br label %10

10:                                               ; preds = %13, %2
  %11 = load ptr, ptr %7, align 8, !tbaa !5
  %12 = icmp ne ptr %11, null
  br i1 %12, label %13, label %19

13:                                               ; preds = %10
  %14 = load ptr, ptr %7, align 8, !tbaa !5
  %15 = getelementptr inbounds %struct.Node, ptr %14, i32 0, i32 1
  %16 = load ptr, ptr %15, align 8, !tbaa !11
  store ptr %16, ptr %7, align 8, !tbaa !5
  %17 = load i32, ptr %5, align 4, !tbaa !9
  %18 = add nsw i32 %17, 1
  store i32 %18, ptr %5, align 4, !tbaa !9
  br label %10, !llvm.loop !13

19:                                               ; preds = %10
  %20 = load i32, ptr %5, align 4, !tbaa !9
  %21 = load i32, ptr %4, align 4, !tbaa !9
  %22 = icmp slt i32 %20, %21
  br i1 %22, label %23, label %24

23:                                               ; preds = %19
  store i32 1, ptr %8, align 4
  br label %45

24:                                               ; preds = %19
  %25 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %25, ptr %7, align 8, !tbaa !5
  store i32 1, ptr %6, align 4, !tbaa !9
  br label %26

26:                                               ; preds = %37, %24
  %27 = load i32, ptr %6, align 4, !tbaa !9
  %28 = load i32, ptr %5, align 4, !tbaa !9
  %29 = load i32, ptr %4, align 4, !tbaa !9
  %30 = sub nsw i32 %28, %29
  %31 = add nsw i32 %30, 1
  %32 = icmp slt i32 %27, %31
  br i1 %32, label %33, label %40

33:                                               ; preds = %26
  %34 = load ptr, ptr %7, align 8, !tbaa !5
  %35 = getelementptr inbounds %struct.Node, ptr %34, i32 0, i32 1
  %36 = load ptr, ptr %35, align 8, !tbaa !11
  store ptr %36, ptr %7, align 8, !tbaa !5
  br label %37

37:                                               ; preds = %33
  %38 = load i32, ptr %6, align 4, !tbaa !9
  %39 = add nsw i32 %38, 1
  store i32 %39, ptr %6, align 4, !tbaa !9
  br label %26, !llvm.loop !15

40:                                               ; preds = %26
  %41 = load ptr, ptr %7, align 8, !tbaa !5
  %42 = getelementptr inbounds %struct.Node, ptr %41, i32 0, i32 0
  %43 = load i32, ptr %42, align 8, !tbaa !16
  %44 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, i32 noundef %43)
  store i32 1, ptr %8, align 4
  br label %45

45:                                               ; preds = %40, %23
  call void @llvm.lifetime.end.p0(i64 8, ptr %7) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  ret void
}

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

declare noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8), i32 noundef) #2

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

attributes #0 = { mustprogress 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 = { "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 #3 = { 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, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!12, !6, i64 8}
!12 = !{!"_ZTS4Node", !10, i64 0, !6, i64 8}
!13 = distinct !{!13, !14}
!14 = !{!"llvm.loop.mustprogress"}
!15 = distinct !{!15, !14}
!16 = !{!12, !10, i64 0}


; 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"

%"class.std::basic_ostream" = type { ptr, %"class.std::basic_ios" }
%"class.std::basic_ios" = type { %"class.std::ios_base", ptr, i8, i8, ptr, ptr, ptr, ptr }
%"class.std::ios_base" = type { ptr, i64, i64, i32, i32, i32, ptr, %"struct.std::ios_base::_Words", [8 x %"struct.std::ios_base::_Words"], i32, ptr, %"class.std::locale" }
%"struct.std::ios_base::_Words" = type { ptr, i64 }
%"class.std::locale" = type { ptr }

@_ZSt4cout = external global %"class.std::basic_ostream", align 8

; Function Attrs: mustprogress uwtable
define dso_local void @_Z16printNthFromLastP4Nodei(ptr noundef readonly %0, i32 noundef %1) local_unnamed_addr #0 {
  %.not16 = icmp eq ptr %0, null
  br i1 %.not16, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %2, %.lr.ph
  %.018 = phi ptr [ %4, %.lr.ph ], [ %0, %2 ]
  %.01317 = phi i32 [ %5, %.lr.ph ], [ 0, %2 ]
  %3 = getelementptr inbounds i8, ptr %.018, i64 8
  %4 = load ptr, ptr %3, align 8, !tbaa !5
  %5 = add nuw nsw i32 %.01317, 1
  %.not = icmp eq ptr %4, null
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !11

._crit_edge:                                      ; preds = %.lr.ph, %2
  %.013.lcssa = phi i32 [ 0, %2 ], [ %5, %.lr.ph ]
  %6 = icmp slt i32 %.013.lcssa, %1
  br i1 %6, label %30, label %.preheader

.preheader:                                       ; preds = %._crit_edge
  %.not1519.not = icmp sgt i32 %.013.lcssa, %1
  br i1 %.not1519.not, label %.lr.ph22.preheader, label %._crit_edge23

.lr.ph22.preheader:                               ; preds = %.preheader
  %7 = sub i32 %.013.lcssa, %1
  %xtraiter = and i32 %7, 7
  %8 = sub i32 %1, %.013.lcssa
  %9 = icmp ugt i32 %8, -8
  br i1 %9, label %._crit_edge23.loopexit.unr-lcssa, label %.lr.ph22.preheader.new

.lr.ph22.preheader.new:                           ; preds = %.lr.ph22.preheader
  %unroll_iter = and i32 %7, -8
  br label %.lr.ph22

.lr.ph22:                                         ; preds = %.lr.ph22, %.lr.ph22.preheader.new
  %.121 = phi ptr [ %0, %.lr.ph22.preheader.new ], [ %25, %.lr.ph22 ]
  %niter = phi i32 [ 0, %.lr.ph22.preheader.new ], [ %niter.next.7, %.lr.ph22 ]
  %10 = getelementptr inbounds i8, ptr %.121, i64 8
  %11 = load ptr, ptr %10, align 8, !tbaa !5
  %12 = getelementptr inbounds i8, ptr %11, i64 8
  %13 = load ptr, ptr %12, align 8, !tbaa !5
  %14 = getelementptr inbounds i8, ptr %13, i64 8
  %15 = load ptr, ptr %14, align 8, !tbaa !5
  %16 = getelementptr inbounds i8, ptr %15, i64 8
  %17 = load ptr, ptr %16, align 8, !tbaa !5
  %18 = getelementptr inbounds i8, ptr %17, i64 8
  %19 = load ptr, ptr %18, align 8, !tbaa !5
  %20 = getelementptr inbounds i8, ptr %19, i64 8
  %21 = load ptr, ptr %20, align 8, !tbaa !5
  %22 = getelementptr inbounds i8, ptr %21, i64 8
  %23 = load ptr, ptr %22, align 8, !tbaa !5
  %24 = getelementptr inbounds i8, ptr %23, i64 8
  %25 = load ptr, ptr %24, align 8, !tbaa !5
  %niter.next.7 = add i32 %niter, 8
  %niter.ncmp.7 = icmp eq i32 %niter.next.7, %unroll_iter
  br i1 %niter.ncmp.7, label %._crit_edge23.loopexit.unr-lcssa, label %.lr.ph22, !llvm.loop !13

._crit_edge23.loopexit.unr-lcssa:                 ; preds = %.lr.ph22, %.lr.ph22.preheader
  %.lcssa.ph = phi ptr [ poison, %.lr.ph22.preheader ], [ %25, %.lr.ph22 ]
  %.121.unr = phi ptr [ %0, %.lr.ph22.preheader ], [ %25, %.lr.ph22 ]
  %lcmp.mod.not = icmp eq i32 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge23, label %.lr.ph22.epil

.lr.ph22.epil:                                    ; preds = %._crit_edge23.loopexit.unr-lcssa, %.lr.ph22.epil
  %.121.epil = phi ptr [ %27, %.lr.ph22.epil ], [ %.121.unr, %._crit_edge23.loopexit.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.lr.ph22.epil ], [ 0, %._crit_edge23.loopexit.unr-lcssa ]
  %26 = getelementptr inbounds i8, ptr %.121.epil, i64 8
  %27 = load ptr, ptr %26, align 8, !tbaa !5
  %epil.iter.next = add i32 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i32 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge23, label %.lr.ph22.epil, !llvm.loop !14

._crit_edge23:                                    ; preds = %._crit_edge23.loopexit.unr-lcssa, %.lr.ph22.epil, %.preheader
  %.1.lcssa = phi ptr [ %0, %.preheader ], [ %.lcssa.ph, %._crit_edge23.loopexit.unr-lcssa ], [ %27, %.lr.ph22.epil ]
  %28 = load i32, ptr %.1.lcssa, align 8, !tbaa !16
  %29 = tail call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, i32 noundef %28)
  br label %30

30:                                               ; preds = %._crit_edge, %._crit_edge23
  ret void
}

declare noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8), i32 noundef) local_unnamed_addr #1

attributes #0 = { mustprogress 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 = { "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"}
!13 = distinct !{!13, !12}
!14 = distinct !{!14, !15}
!15 = !{!"llvm.loop.unroll.disable"}
!16 = !{!6, !7, i64 0}


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