; LLVM IR from next-step-for-interview-prep/Coding-Ninjas-DSA-course_code_and_notes_cpp :: 1/0000000000000262/LinkedList.ll (Z9takeInputv)

; 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_istream" = type { ptr, i64, %"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 }
%class.Node = type { i32, ptr }

@_ZSt3cin = external global %"class.std::basic_istream", align 8

; Function Attrs: mustprogress uwtable
define dso_local noundef ptr @_Z9takeInputv() #0 personality ptr @__gxx_personality_v0 {
  %1 = alloca i32, align 4
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca ptr, align 8
  call void @llvm.lifetime.start.p0(i64 4, ptr %1) #6
  %7 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %1)
  call void @llvm.lifetime.start.p0(i64 8, ptr %2) #6
  store ptr null, ptr %2, align 8, !tbaa !5
  br label %8

8:                                                ; preds = %38, %0
  %9 = load i32, ptr %1, align 4, !tbaa !9
  %10 = icmp ne i32 %9, -1
  br i1 %10, label %11, label %40

11:                                               ; preds = %8
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #6
  %12 = call noalias noundef nonnull ptr @_Znwm(i64 noundef 16) #7
  %13 = load i32, ptr %1, align 4, !tbaa !9
  invoke void @_ZN4NodeC2Ei(ptr noundef nonnull align 8 dereferenceable(16) %12, i32 noundef %13)
          to label %14 unwind label %19

14:                                               ; preds = %11
  store ptr %12, ptr %3, align 8, !tbaa !5
  %15 = load ptr, ptr %2, align 8, !tbaa !5
  %16 = icmp eq ptr %15, null
  br i1 %16, label %17, label %23

17:                                               ; preds = %14
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %18, ptr %2, align 8, !tbaa !5
  br label %38

19:                                               ; preds = %11
  %20 = landingpad { ptr, i32 }
          cleanup
  %21 = extractvalue { ptr, i32 } %20, 0
  store ptr %21, ptr %4, align 8
  %22 = extractvalue { ptr, i32 } %20, 1
  store i32 %22, ptr %5, align 4
  call void @_ZdlPvm(ptr noundef %12, i64 noundef 16) #8
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #6
  call void @llvm.lifetime.end.p0(i64 8, ptr %2) #6
  call void @llvm.lifetime.end.p0(i64 4, ptr %1) #6
  br label %42

23:                                               ; preds = %14
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #6
  %24 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %24, ptr %6, align 8, !tbaa !5
  br label %25

25:                                               ; preds = %30, %23
  %26 = load ptr, ptr %6, align 8, !tbaa !5
  %27 = getelementptr inbounds %class.Node, ptr %26, i32 0, i32 1
  %28 = load ptr, ptr %27, align 8, !tbaa !11
  %29 = icmp ne ptr %28, null
  br i1 %29, label %30, label %34

30:                                               ; preds = %25
  %31 = load ptr, ptr %6, align 8, !tbaa !5
  %32 = getelementptr inbounds %class.Node, ptr %31, i32 0, i32 1
  %33 = load ptr, ptr %32, align 8, !tbaa !11
  store ptr %33, ptr %6, align 8, !tbaa !5
  br label %25, !llvm.loop !13

34:                                               ; preds = %25
  %35 = load ptr, ptr %3, align 8, !tbaa !5
  %36 = load ptr, ptr %6, align 8, !tbaa !5
  %37 = getelementptr inbounds %class.Node, ptr %36, i32 0, i32 1
  store ptr %35, ptr %37, align 8, !tbaa !11
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #6
  br label %38

38:                                               ; preds = %34, %17
  %39 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %1)
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #6
  br label %8, !llvm.loop !15

40:                                               ; preds = %8
  %41 = load ptr, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %2) #6
  call void @llvm.lifetime.end.p0(i64 4, ptr %1) #6
  ret ptr %41

42:                                               ; preds = %19
  %43 = load ptr, ptr %4, align 8
  %44 = load i32, ptr %5, align 4
  %45 = insertvalue { ptr, i32 } poison, ptr %43, 0
  %46 = insertvalue { ptr, i32 } %45, i32 %44, 1
  resume { ptr, i32 } %46
}

; 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(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16), ptr noundef nonnull align 4 dereferenceable(4)) #2

; Function Attrs: nobuiltin allocsize(0)
declare noundef nonnull ptr @_Znwm(i64 noundef) #3

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZN4NodeC2Ei(ptr noundef nonnull align 8 dereferenceable(16), i32 noundef) unnamed_addr #4 align 2

declare i32 @__gxx_personality_v0(...)

; Function Attrs: nobuiltin nounwind
declare void @_ZdlPvm(ptr noundef, i64 noundef) #5

; 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 = { nobuiltin allocsize(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 #4 = { 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 #5 = { nobuiltin nounwind "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 #6 = { nounwind }
attributes #7 = { builtin allocsize(0) }
attributes #8 = { builtin 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}


; 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_istream" = type { ptr, i64, %"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 }

@_ZSt3cin = external global %"class.std::basic_istream", align 8

; Function Attrs: mustprogress uwtable
define dso_local noundef ptr @_Z9takeInputv() local_unnamed_addr #0 personality ptr @__gxx_personality_v0 {
  %1 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %1) #5
  %2 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %1)
  %3 = load i32, ptr %1, align 4, !tbaa !5
  %.not11 = icmp eq i32 %3, -1
  br i1 %.not11, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %0, %11
  %4 = phi i32 [ %13, %11 ], [ %3, %0 ]
  %.0812 = phi ptr [ %.1, %11 ], [ null, %0 ]
  %5 = call noalias noundef nonnull dereferenceable(16) ptr @_Znwm(i64 noundef 16) #6
  call void @_ZN4NodeC2Ei(ptr noundef nonnull align 8 dereferenceable(16) %5, i32 noundef %4)
  %6 = icmp eq ptr %.0812, null
  br i1 %6, label %11, label %.preheader

.preheader:                                       ; preds = %.lr.ph, %.preheader
  %.0 = phi ptr [ %8, %.preheader ], [ %.0812, %.lr.ph ]
  %7 = getelementptr inbounds i8, ptr %.0, i64 8
  %8 = load ptr, ptr %7, align 8, !tbaa !9
  %.not10 = icmp eq ptr %8, null
  br i1 %.not10, label %9, label %.preheader, !llvm.loop !12

9:                                                ; preds = %.preheader
  %10 = getelementptr inbounds i8, ptr %.0, i64 8
  store ptr %5, ptr %10, align 8, !tbaa !9
  br label %11

11:                                               ; preds = %.lr.ph, %9
  %.1 = phi ptr [ %.0812, %9 ], [ %5, %.lr.ph ]
  %12 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %1)
  %13 = load i32, ptr %1, align 4, !tbaa !5
  %.not = icmp eq i32 %13, -1
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !14

._crit_edge:                                      ; preds = %11, %0
  %.08.lcssa = phi ptr [ null, %0 ], [ %.1, %11 ]
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %1) #5
  ret ptr %.08.lcssa
}

; Function Attrs: mustprogress 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(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16), ptr noundef nonnull align 4 dereferenceable(4)) local_unnamed_addr #2

; Function Attrs: nobuiltin allocsize(0)
declare noundef nonnull ptr @_Znwm(i64 noundef) local_unnamed_addr #3

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZN4NodeC2Ei(ptr noundef nonnull align 8 dereferenceable(16), i32 noundef) unnamed_addr #4 align 2

declare i32 @__gxx_personality_v0(...)

; Function Attrs: mustprogress 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 = { mustprogress 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 = { nobuiltin allocsize(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 #4 = { 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 #5 = { nounwind }
attributes #6 = { builtin allocsize(0) }

!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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !11, i64 8}
!10 = !{!"_ZTS4Node", !6, i64 0, !11, i64 8}
!11 = !{!"any pointer", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}
!14 = distinct !{!14, !13}


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