; LLVM IR from next-step-for-interview-prep/Coding-Ninjas-DSA-course_code_and_notes_cpp :: Milestone-3=DSA/questions and solutions/Assignment-1b=Recursion (04-Pair_star)

; 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.__gnu_cxx::__normal_iterator" = type { ptr }

; Function Attrs: mustprogress uwtable
define dso_local noundef i32 @_Z14largestElementRSt6vectorIiSaIiEEi(ptr noundef nonnull align 8 dereferenceable(24) %0, i32 noundef %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca ptr, align 8
  %7 = alloca %"class.__gnu_cxx::__normal_iterator", align 8
  %8 = alloca %"class.__gnu_cxx::__normal_iterator", align 8
  %9 = 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) #4
  store i32 0, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #4
  %10 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %10, ptr %6, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %7) #4
  %11 = load ptr, ptr %6, align 8, !tbaa !5
  %12 = call ptr @_ZNSt6vectorIiSaIiEE5beginEv(ptr noundef nonnull align 8 dereferenceable(24) %11) #4
  %13 = getelementptr inbounds %"class.__gnu_cxx::__normal_iterator", ptr %7, i32 0, i32 0
  store ptr %12, ptr %13, align 8
  call void @llvm.lifetime.start.p0(i64 8, ptr %8) #4
  %14 = load ptr, ptr %6, align 8, !tbaa !5
  %15 = call ptr @_ZNSt6vectorIiSaIiEE3endEv(ptr noundef nonnull align 8 dereferenceable(24) %14) #4
  %16 = getelementptr inbounds %"class.__gnu_cxx::__normal_iterator", ptr %8, i32 0, i32 0
  store ptr %15, ptr %16, align 8
  br label %17

17:                                               ; preds = %25, %2
  %18 = call noundef zeroext i1 @_ZN9__gnu_cxxneIPiSt6vectorIiSaIiEEEEbRKNS_17__normal_iteratorIT_T0_EESA_(ptr noundef nonnull align 8 dereferenceable(8) %7, ptr noundef nonnull align 8 dereferenceable(8) %8) #4
  br i1 %18, label %20, label %19

19:                                               ; preds = %17
  call void @llvm.lifetime.end.p0(i64 8, ptr %8) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %7) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #4
  br label %27

20:                                               ; preds = %17
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #4
  %21 = call noundef nonnull align 4 dereferenceable(4) ptr @_ZNK9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEdeEv(ptr noundef nonnull align 8 dereferenceable(8) %7) #4
  %22 = load i32, ptr %21, align 4, !tbaa !9
  store i32 %22, ptr %9, align 4, !tbaa !9
  %23 = call noundef nonnull align 4 dereferenceable(4) ptr @_ZSt3maxIiERKT_S2_S2_(ptr noundef nonnull align 4 dereferenceable(4) %5, ptr noundef nonnull align 4 dereferenceable(4) %9)
  %24 = load i32, ptr %23, align 4, !tbaa !9
  store i32 %24, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #4
  br label %25

25:                                               ; preds = %20
  %26 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZN9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEppEv(ptr noundef nonnull align 8 dereferenceable(8) %7) #4
  br label %17

27:                                               ; preds = %19
  %28 = load i32, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #4
  ret i32 %28
}

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

; Function Attrs: mustprogress nounwind uwtable
declare dso_local ptr @_ZNSt6vectorIiSaIiEE5beginEv(ptr noundef nonnull align 8 dereferenceable(24)) #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local ptr @_ZNSt6vectorIiSaIiEE3endEv(ptr noundef nonnull align 8 dereferenceable(24)) #2 align 2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_ZN9__gnu_cxxneIPiSt6vectorIiSaIiEEEEbRKNS_17__normal_iteratorIT_T0_EESA_(ptr noundef nonnull align 8 dereferenceable(8), ptr noundef nonnull align 8 dereferenceable(8)) #3

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 4 dereferenceable(4) ptr @_ZNK9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEdeEv(ptr noundef nonnull align 8 dereferenceable(8)) #2 align 2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local noundef nonnull align 4 dereferenceable(4) ptr @_ZSt3maxIiERKT_S2_S2_(ptr noundef nonnull align 4 dereferenceable(4), ptr noundef nonnull align 4 dereferenceable(4)) #3

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

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 8 dereferenceable(8) ptr @_ZN9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEppEv(ptr noundef nonnull align 8 dereferenceable(8)) #2 align 2

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 = { 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 #3 = { inlinehint 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 #4 = { 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}


; 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.__gnu_cxx::__normal_iterator" = type { ptr }

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z14largestElementRSt6vectorIiSaIiEEi(ptr noundef nonnull align 8 dereferenceable(24) %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = alloca i32, align 4
  %4 = alloca %"class.__gnu_cxx::__normal_iterator", align 8
  %5 = alloca %"class.__gnu_cxx::__normal_iterator", align 8
  %6 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %3) #3
  store i32 0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr nonnull %4) #3
  %7 = tail call ptr @_ZNSt6vectorIiSaIiEE5beginEv(ptr noundef nonnull align 8 dereferenceable(24) %0) #3
  store ptr %7, ptr %4, align 8
  call void @llvm.lifetime.start.p0(i64 8, ptr nonnull %5) #3
  %8 = tail call ptr @_ZNSt6vectorIiSaIiEE3endEv(ptr noundef nonnull align 8 dereferenceable(24) %0) #3
  store ptr %8, ptr %5, align 8
  %9 = call noundef zeroext i1 @_ZN9__gnu_cxxneIPiSt6vectorIiSaIiEEEEbRKNS_17__normal_iteratorIT_T0_EESA_(ptr noundef nonnull align 8 dereferenceable(8) %4, ptr noundef nonnull align 8 dereferenceable(8) %5) #3
  br i1 %9, label %.lr.ph, label %._crit_edge

._crit_edge.loopexit:                             ; preds = %.lr.ph
  %.pre = load i32, ptr %3, align 4, !tbaa !5
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %2
  %10 = phi i32 [ %.pre, %._crit_edge.loopexit ], [ 0, %2 ]
  call void @llvm.lifetime.end.p0(i64 8, ptr nonnull %5) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr nonnull %4) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %3) #3
  ret i32 %10

.lr.ph:                                           ; preds = %2, %.lr.ph
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %6) #3
  %11 = call noundef nonnull align 4 dereferenceable(4) ptr @_ZNK9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEdeEv(ptr noundef nonnull align 8 dereferenceable(8) %4) #3
  %12 = load i32, ptr %11, align 4, !tbaa !5
  store i32 %12, ptr %6, align 4, !tbaa !5
  %13 = call noundef nonnull align 4 dereferenceable(4) ptr @_ZSt3maxIiERKT_S2_S2_(ptr noundef nonnull align 4 dereferenceable(4) %3, ptr noundef nonnull align 4 dereferenceable(4) %6)
  %14 = load i32, ptr %13, align 4, !tbaa !5
  store i32 %14, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %6) #3
  %15 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZN9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEppEv(ptr noundef nonnull align 8 dereferenceable(8) %4) #3
  %16 = call noundef zeroext i1 @_ZN9__gnu_cxxneIPiSt6vectorIiSaIiEEEEbRKNS_17__normal_iteratorIT_T0_EESA_(ptr noundef nonnull align 8 dereferenceable(8) %4, ptr noundef nonnull align 8 dereferenceable(8) %5) #3
  br i1 %16, label %.lr.ph, label %._crit_edge.loopexit
}

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

; Function Attrs: mustprogress nounwind uwtable
declare dso_local ptr @_ZNSt6vectorIiSaIiEE5beginEv(ptr noundef nonnull align 8 dereferenceable(24)) local_unnamed_addr #0 align 2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local ptr @_ZNSt6vectorIiSaIiEE3endEv(ptr noundef nonnull align 8 dereferenceable(24)) local_unnamed_addr #0 align 2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_ZN9__gnu_cxxneIPiSt6vectorIiSaIiEEEEbRKNS_17__normal_iteratorIT_T0_EESA_(ptr noundef nonnull align 8 dereferenceable(8), ptr noundef nonnull align 8 dereferenceable(8)) local_unnamed_addr #2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 4 dereferenceable(4) ptr @_ZNK9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEdeEv(ptr noundef nonnull align 8 dereferenceable(8)) local_unnamed_addr #0 align 2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local noundef nonnull align 4 dereferenceable(4) ptr @_ZSt3maxIiERKT_S2_S2_(ptr noundef nonnull align 4 dereferenceable(4), ptr noundef nonnull align 4 dereferenceable(4)) local_unnamed_addr #2

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

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 8 dereferenceable(8) ptr @_ZN9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEppEv(ptr noundef nonnull align 8 dereferenceable(8)) local_unnamed_addr #0 align 2

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 = { mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { inlinehint 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 #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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass