; LLVM IR from tangjz/acm-icpc :: lydsy (1968)

; 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"

@n = external dso_local global i32, align 4
@ans = external dso_local global i32, align 4
@.str = external hidden unnamed_addr constant [3 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [4 x i8], align 1

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() #0 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  %3 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str, ptr noundef @n)
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #3
  store i32 1, ptr %2, align 4, !tbaa !5
  br label %4

4:                                                ; preds = %15, %0
  %5 = load i32, ptr %2, align 4, !tbaa !5
  %6 = load i32, ptr @n, align 4, !tbaa !5
  %7 = icmp sle i32 %5, %6
  br i1 %7, label %9, label %8

8:                                                ; preds = %4
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #3
  br label %18

9:                                                ; preds = %4
  %10 = load i32, ptr @n, align 4, !tbaa !5
  %11 = load i32, ptr %2, align 4, !tbaa !5
  %12 = sdiv i32 %10, %11
  %13 = load i32, ptr @ans, align 4, !tbaa !5
  %14 = add nsw i32 %13, %12
  store i32 %14, ptr @ans, align 4, !tbaa !5
  br label %15

15:                                               ; preds = %9
  %16 = load i32, ptr %2, align 4, !tbaa !5
  %17 = add nsw i32 %16, 1
  store i32 %17, ptr %2, align 4, !tbaa !5
  br label %4, !llvm.loop !9

18:                                               ; preds = %8
  %19 = load i32, ptr @ans, align 4, !tbaa !5
  %20 = call i32 (ptr, ...) @printf(ptr noundef @.str.1, i32 noundef %19)
  ret i32 0
}

declare i32 @__isoc99_scanf(ptr noundef, ...) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #2

declare i32 @printf(ptr noundef, ...) #1

attributes #0 = { 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 #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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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"

@n = external dso_local global i32, align 4
@ans = external dso_local local_unnamed_addr global i32, align 4
@.str = external hidden unnamed_addr constant [3 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [4 x i8], align 1

; Function Attrs: mustprogress nofree norecurse nounwind uwtable
define dso_local noundef i32 @main() local_unnamed_addr #0 {
  %1 = tail call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str, ptr noundef nonnull @n)
  %2 = load i32, ptr @n, align 4, !tbaa !5
  %ans.promoted = load i32, ptr @ans, align 4, !tbaa !5
  %.not4 = icmp slt i32 %2, 1
  br i1 %.not4, label %8, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %0
  %xtraiter = and i32 %2, 3
  %3 = icmp ult i32 %2, 4
  br i1 %3, label %._crit_edge.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i32 %2, 2147483644
  br label %.lr.ph

._crit_edge.unr-lcssa:                            ; preds = %.lr.ph, %.lr.ph.preheader
  %.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %22, %.lr.ph ]
  %.05.unr = phi i32 [ 1, %.lr.ph.preheader ], [ %23, %.lr.ph ]
  %.unr = phi i32 [ %ans.promoted, %.lr.ph.preheader ], [ %22, %.lr.ph ]
  %lcmp.mod.not = icmp eq i32 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.unr-lcssa, %.lr.ph.epil
  %.05.epil = phi i32 [ %7, %.lr.ph.epil ], [ %.05.unr, %._crit_edge.unr-lcssa ]
  %4 = phi i32 [ %6, %.lr.ph.epil ], [ %.unr, %._crit_edge.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.unr-lcssa ]
  %5 = udiv i32 %2, %.05.epil
  %6 = add nsw i32 %4, %5
  %7 = add nuw i32 %.05.epil, 1
  %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_edge, label %.lr.ph.epil, !llvm.loop !9

._crit_edge:                                      ; preds = %.lr.ph.epil, %._crit_edge.unr-lcssa
  %.lcssa = phi i32 [ %.lcssa.ph, %._crit_edge.unr-lcssa ], [ %6, %.lr.ph.epil ]
  store i32 %.lcssa, ptr @ans, align 4, !tbaa !5
  br label %8

8:                                                ; preds = %._crit_edge, %0
  %9 = phi i32 [ %.lcssa, %._crit_edge ], [ %ans.promoted, %0 ]
  %10 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.1, i32 noundef %9)
  ret i32 0

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %.05 = phi i32 [ 1, %.lr.ph.preheader.new ], [ %23, %.lr.ph ]
  %11 = phi i32 [ %ans.promoted, %.lr.ph.preheader.new ], [ %22, %.lr.ph ]
  %niter = phi i32 [ 0, %.lr.ph.preheader.new ], [ %niter.next.3, %.lr.ph ]
  %12 = udiv i32 %2, %.05
  %13 = add nsw i32 %11, %12
  %14 = add nuw nsw i32 %.05, 1
  %15 = udiv i32 %2, %14
  %16 = add nsw i32 %13, %15
  %17 = add nuw nsw i32 %.05, 2
  %18 = udiv i32 %2, %17
  %19 = add nsw i32 %16, %18
  %20 = add nuw i32 %.05, 3
  %21 = udiv i32 %2, %20
  %22 = add nsw i32 %19, %21
  %23 = add nuw i32 %.05, 4
  %niter.next.3 = add i32 %niter, 4
  %niter.ncmp.3 = icmp eq i32 %niter.next.3, %unroll_iter
  br i1 %niter.ncmp.3, label %._crit_edge.unr-lcssa, label %.lr.ph, !llvm.loop !11
}

; Function Attrs: nofree nounwind
declare noundef i32 @__isoc99_scanf(ptr nocapture noundef readonly, ...) local_unnamed_addr #1

; Function Attrs: nofree nounwind
declare noundef i32 @printf(ptr nocapture noundef readonly, ...) local_unnamed_addr #1

attributes #0 = { mustprogress nofree norecurse 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 = { nofree 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" }

!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.unroll.disable"}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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