; LLVM IR from upupming/algorithm :: acwing/算法竞赛进阶指南/0x28-IDA-Star/180. 排书 (main)

; 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 }
%"class.std::basic_istream" = type { ptr, i64, %"class.std::basic_ios" }

@n = external dso_local global i32, align 4
@t = external dso_local global i32, align 4
@b = external dso_local global [15 x i32], align 16
@e = external dso_local global i32, align 4
@_ZSt4cout = external global %"class.std::basic_ostream", align 8
@_ZSt3cin = external global %"class.std::basic_istream", align 8
@.str.1 = external hidden unnamed_addr constant [10 x i8], align 1

; 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: inlinehint mustprogress uwtable
declare noundef nonnull align 8 dereferenceable(8) ptr @_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(ptr noundef nonnull align 8 dereferenceable(8), ptr noundef) #1

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

; Function Attrs: mustprogress uwtable
declare noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEPFRSoS_E(ptr noundef nonnull align 8 dereferenceable(8), ptr noundef) #3 align 2

; Function Attrs: inlinehint mustprogress uwtable
declare noundef nonnull align 8 dereferenceable(8) ptr @_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_(ptr noundef nonnull align 8 dereferenceable(8)) #1

; Function Attrs: mustprogress uwtable
declare dso_local noundef zeroext i1 @_Z3dfsi(i32 noundef) #3

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() #4 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  %3 = alloca i8, align 1
  store i32 0, ptr %1, align 4
  %4 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) @t)
  br label %5

5:                                                ; preds = %43, %0
  %6 = load i32, ptr @t, align 4, !tbaa !5
  %7 = add nsw i32 %6, -1
  store i32 %7, ptr @t, align 4, !tbaa !5
  %8 = icmp ne i32 %6, 0
  br i1 %8, label %9, label %44

9:                                                ; preds = %5
  %10 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) @n)
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #5
  store i32 0, ptr %2, align 4, !tbaa !5
  br label %11

11:                                               ; preds = %21, %9
  %12 = load i32, ptr %2, align 4, !tbaa !5
  %13 = load i32, ptr @n, align 4, !tbaa !5
  %14 = icmp slt i32 %12, %13
  br i1 %14, label %16, label %15

15:                                               ; preds = %11
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #5
  br label %24

16:                                               ; preds = %11
  %17 = load i32, ptr %2, align 4, !tbaa !5
  %18 = sext i32 %17 to i64
  %19 = getelementptr inbounds [15 x i32], ptr @b, i64 0, i64 %18
  %20 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %19)
  br label %21

21:                                               ; preds = %16
  %22 = load i32, ptr %2, align 4, !tbaa !5
  %23 = add nsw i32 %22, 1
  store i32 %23, ptr %2, align 4, !tbaa !5
  br label %11, !llvm.loop !9

24:                                               ; preds = %15
  store i32 0, ptr @e, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 1, ptr %3) #5
  store i8 0, ptr %3, align 1, !tbaa !11
  br label %25

25:                                               ; preds = %34, %24
  %26 = load i32, ptr @e, align 4, !tbaa !5
  %27 = icmp sle i32 %26, 4
  br i1 %27, label %28, label %37

28:                                               ; preds = %25
  %29 = call noundef zeroext i1 @_Z3dfsi(i32 noundef 0)
  br i1 %29, label %30, label %34

30:                                               ; preds = %28
  %31 = load i32, ptr @e, align 4, !tbaa !5
  %32 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, i32 noundef %31)
  %33 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEPFRSoS_E(ptr noundef nonnull align 8 dereferenceable(8) %32, ptr noundef @_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_)
  store i8 1, ptr %3, align 1, !tbaa !11
  br label %37

34:                                               ; preds = %28
  %35 = load i32, ptr @e, align 4, !tbaa !5
  %36 = add nsw i32 %35, 1
  store i32 %36, ptr @e, align 4, !tbaa !5
  br label %25, !llvm.loop !13

37:                                               ; preds = %30, %25
  %38 = load i8, ptr %3, align 1, !tbaa !11, !range !14, !noundef !15
  %39 = trunc i8 %38 to i1
  br i1 %39, label %43, label %40

40:                                               ; preds = %37
  %41 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, ptr noundef @.str.1)
  %42 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEPFRSoS_E(ptr noundef nonnull align 8 dereferenceable(8) %41, ptr noundef @_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_)
  br label %43

43:                                               ; preds = %40, %37
  call void @llvm.lifetime.end.p0(i64 1, ptr %3) #5
  br label %5, !llvm.loop !16

44:                                               ; preds = %5
  ret i32 0
}

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

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { inlinehint 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 #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 = { 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 #4 = { mustprogress norecurse 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 }

!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 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}
!11 = !{!12, !12, i64 0}
!12 = !{!"bool", !7, i64 0}
!13 = distinct !{!13, !10}
!14 = !{i8 0, i8 2}
!15 = !{}
!16 = distinct !{!16, !10}


; 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 }
%"class.std::basic_istream" = type { ptr, i64, %"class.std::basic_ios" }

@n = external dso_local global i32, align 4
@t = external dso_local global i32, align 4
@b = external dso_local global [15 x i32], align 16
@e = external dso_local local_unnamed_addr global i32, align 4
@_ZSt4cout = external global %"class.std::basic_ostream", align 8
@_ZSt3cin = external global %"class.std::basic_istream", align 8
@.str.1 = external hidden unnamed_addr constant [10 x i8], align 1

; Function Attrs: inlinehint mustprogress uwtable
declare noundef nonnull align 8 dereferenceable(8) ptr @_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(ptr noundef nonnull align 8 dereferenceable(8), ptr noundef) local_unnamed_addr #0

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

; Function Attrs: mustprogress uwtable
declare noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEPFRSoS_E(ptr noundef nonnull align 8 dereferenceable(8), ptr noundef) local_unnamed_addr #2 align 2

; Function Attrs: inlinehint mustprogress uwtable
declare noundef nonnull align 8 dereferenceable(8) ptr @_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_(ptr noundef nonnull align 8 dereferenceable(8)) #0

; Function Attrs: mustprogress uwtable
declare dso_local noundef zeroext i1 @_Z3dfsi(i32 noundef) local_unnamed_addr #2

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() local_unnamed_addr #3 {
  %1 = tail call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) @t)
  %2 = load i32, ptr @t, align 4, !tbaa !5
  %3 = add nsw i32 %2, -1
  store i32 %3, ptr @t, align 4, !tbaa !5
  %.not6 = icmp eq i32 %2, 0
  br i1 %.not6, label %._crit_edge, label %.lr.ph7

.lr.ph7:                                          ; preds = %0, %21
  %4 = tail call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) @n)
  %5 = load i32, ptr @n, align 4, !tbaa !5
  %6 = icmp sgt i32 %5, 0
  br i1 %6, label %.lr.ph, label %.preheader

.preheader:                                       ; preds = %.lr.ph, %.lr.ph7
  store i32 0, ptr @e, align 4, !tbaa !5
  br label %12

.lr.ph:                                           ; preds = %.lr.ph7, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %.lr.ph7 ]
  %7 = getelementptr inbounds [15 x i32], ptr @b, i64 0, i64 %indvars.iv
  %8 = tail call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %7)
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %9 = load i32, ptr @n, align 4, !tbaa !5
  %10 = sext i32 %9 to i64
  %11 = icmp slt i64 %indvars.iv.next, %10
  br i1 %11, label %.lr.ph, label %.preheader, !llvm.loop !9

12:                                               ; preds = %.preheader, %17
  %13 = tail call noundef zeroext i1 @_Z3dfsi(i32 noundef 0)
  %14 = load i32, ptr @e, align 4, !tbaa !5
  br i1 %13, label %15, label %17

15:                                               ; preds = %12
  %16 = tail call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, i32 noundef %14)
  br label %21

17:                                               ; preds = %12
  %18 = add nsw i32 %14, 1
  store i32 %18, ptr @e, align 4, !tbaa !5
  %19 = icmp slt i32 %14, 4
  br i1 %19, label %12, label %.critedge, !llvm.loop !11

.critedge:                                        ; preds = %17
  %20 = tail call noundef nonnull align 8 dereferenceable(8) ptr @_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, ptr noundef nonnull @.str.1)
  br label %21

21:                                               ; preds = %15, %.critedge
  %.sink = phi ptr [ %16, %15 ], [ %20, %.critedge ]
  %22 = tail call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEPFRSoS_E(ptr noundef nonnull align 8 dereferenceable(8) %.sink, ptr noundef nonnull @_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_)
  %23 = load i32, ptr @t, align 4, !tbaa !5
  %24 = add nsw i32 %23, -1
  store i32 %24, ptr @t, align 4, !tbaa !5
  %.not = icmp eq i32 %23, 0
  br i1 %.not, label %._crit_edge, label %.lr.ph7, !llvm.loop !12

._crit_edge:                                      ; preds = %21, %0
  ret i32 0
}

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 #1

attributes #0 = { inlinehint 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" }
attributes #2 = { 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 #3 = { mustprogress norecurse 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, !6, i64 0}
!6 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}
!11 = distinct !{!11, !10}
!12 = distinct !{!12, !10}


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