; LLVM IR from upupming/algorithm :: CCCC-GPLT/L2-025 分而治之.ll (Z5checkv)

; 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 }

@n = external dso_local global i32, align 4
@a = external dso_local global [10010 x i32], align 16
@_ZSt4cout = external global %"class.std::basic_ostream", align 8
@.str = external hidden unnamed_addr constant [4 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [5 x i8], align 1

; Function Attrs: mustprogress uwtable
define dso_local void @_Z5checkv() #0 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr %1) #3
  store i32 1, ptr %1, align 4, !tbaa !5
  br label %3

3:                                                ; preds = %17, %0
  %4 = load i32, ptr %1, align 4, !tbaa !5
  %5 = load i32, ptr @n, align 4, !tbaa !5
  %6 = icmp sle i32 %4, %5
  br i1 %6, label %8, label %7

7:                                                ; preds = %3
  store i32 2, ptr %2, align 4
  br label %20

8:                                                ; preds = %3
  %9 = load i32, ptr %1, align 4, !tbaa !5
  %10 = sext i32 %9 to i64
  %11 = getelementptr inbounds [10010 x i32], ptr @a, i64 0, i64 %10
  %12 = load i32, ptr %11, align 4, !tbaa !5
  %13 = icmp sgt i32 %12, 0
  br i1 %13, label %14, label %16

14:                                               ; preds = %8
  %15 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, ptr noundef @.str)
  store i32 1, ptr %2, align 4
  br label %20

16:                                               ; preds = %8
  br label %17

17:                                               ; preds = %16
  %18 = load i32, ptr %1, align 4, !tbaa !5
  %19 = add nsw i32 %18, 1
  store i32 %19, ptr %1, align 4, !tbaa !5
  br label %3, !llvm.loop !9

20:                                               ; preds = %14, %7
  call void @llvm.lifetime.end.p0(i64 4, ptr %1) #3
  %21 = load i32, ptr %2, align 4
  switch i32 %21, label %25 [
    i32 2, label %22
    i32 1, label %24
  ]

22:                                               ; preds = %20
  %23 = 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)
  br label %24

24:                                               ; preds = %22, %20
  ret void

25:                                               ; preds = %20
  unreachable
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #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) #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 = { 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 #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"}
!9 = distinct !{!9, !10}
!10 = !{!"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"

%"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 }

@n = external dso_local local_unnamed_addr global i32, align 4
@a = external dso_local local_unnamed_addr global [10010 x i32], align 16
@_ZSt4cout = external global %"class.std::basic_ostream", align 8
@.str = external hidden unnamed_addr constant [4 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [5 x i8], align 1

; Function Attrs: mustprogress uwtable
define dso_local void @_Z5checkv() local_unnamed_addr #0 {
  %1 = load i32, ptr @n, align 4, !tbaa !5
  %.not8 = icmp slt i32 %1, 1
  br i1 %.not8, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %0
  %2 = add nuw i32 %1, 1
  %wide.trip.count = zext i32 %2 to i64
  br label %.lr.ph

3:                                                ; preds = %.lr.ph
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %exitcond.not = icmp eq i64 %indvars.iv.next, %wide.trip.count
  br i1 %exitcond.not, label %._crit_edge, label %.lr.ph, !llvm.loop !9

.lr.ph:                                           ; preds = %.lr.ph.preheader, %3
  %indvars.iv = phi i64 [ 1, %.lr.ph.preheader ], [ %indvars.iv.next, %3 ]
  %4 = getelementptr inbounds [10010 x i32], ptr @a, i64 0, i64 %indvars.iv
  %5 = load i32, ptr %4, align 4, !tbaa !5
  %6 = icmp sgt i32 %5, 0
  br i1 %6, label %._crit_edge, label %3

._crit_edge:                                      ; preds = %3, %.lr.ph, %0
  %.str.sink = phi ptr [ @.str.1, %0 ], [ @.str, %.lr.ph ], [ @.str.1, %3 ]
  %7 = 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.sink)
  ret void
}

; 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 #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 = { 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" }

!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"}


; Effective O3 passes: CorrelatedValuePropagationPass,GlobalOptPass,IPSCCPPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LICMPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,SROAPass,SimplifyCFGPass,TailCallElimPass