; LLVM IR from tangjz/acm-icpc :: codeforces/gym/101201F.ll (Z4dfs1i)

; 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"

%struct.Edge = type { i32, i32 }

@tot = external dso_local global i32, align 4
@pre = external dso_local global [2001 x i32], align 16
@seq = external dso_local global [2001 x i32], align 16
@vis = external dso_local global [2001 x i8], align 16
@e = external dso_local global [4000003 x %struct.Edge], align 16

; 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: mustprogress uwtable
define dso_local void @_Z4dfs1i(i32 noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  %4 = load i32, ptr %2, align 4, !tbaa !5
  %5 = sext i32 %4 to i64
  %6 = getelementptr inbounds [2001 x i8], ptr @vis, i64 0, i64 %5
  store i8 1, ptr %6, align 1, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  %7 = load i32, ptr %2, align 4, !tbaa !5
  %8 = sext i32 %7 to i64
  %9 = getelementptr inbounds [2001 x i32], ptr @pre, i64 0, i64 %8
  %10 = load i32, ptr %9, align 4, !tbaa !5
  store i32 %10, ptr %3, align 4, !tbaa !5
  br label %11

11:                                               ; preds = %32, %1
  %12 = load i32, ptr %3, align 4, !tbaa !5
  %13 = icmp ne i32 %12, -1
  br i1 %13, label %15, label %14

14:                                               ; preds = %11
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  br label %38

15:                                               ; preds = %11
  %16 = load i32, ptr %3, align 4, !tbaa !5
  %17 = sext i32 %16 to i64
  %18 = getelementptr inbounds [4000003 x %struct.Edge], ptr @e, i64 0, i64 %17
  %19 = getelementptr inbounds %struct.Edge, ptr %18, i32 0, i32 1
  %20 = load i32, ptr %19, align 4, !tbaa !11
  %21 = sext i32 %20 to i64
  %22 = getelementptr inbounds [2001 x i8], ptr @vis, i64 0, i64 %21
  %23 = load i8, ptr %22, align 1, !tbaa !9, !range !13, !noundef !14
  %24 = trunc i8 %23 to i1
  br i1 %24, label %31, label %25

25:                                               ; preds = %15
  %26 = load i32, ptr %3, align 4, !tbaa !5
  %27 = sext i32 %26 to i64
  %28 = getelementptr inbounds [4000003 x %struct.Edge], ptr @e, i64 0, i64 %27
  %29 = getelementptr inbounds %struct.Edge, ptr %28, i32 0, i32 1
  %30 = load i32, ptr %29, align 4, !tbaa !11
  call void @_Z4dfs1i(i32 noundef %30)
  br label %31

31:                                               ; preds = %25, %15
  br label %32

32:                                               ; preds = %31
  %33 = load i32, ptr %3, align 4, !tbaa !5
  %34 = sext i32 %33 to i64
  %35 = getelementptr inbounds [4000003 x %struct.Edge], ptr @e, i64 0, i64 %34
  %36 = getelementptr inbounds %struct.Edge, ptr %35, i32 0, i32 0
  %37 = load i32, ptr %36, align 8, !tbaa !15
  store i32 %37, ptr %3, align 4, !tbaa !5
  br label %11, !llvm.loop !16

38:                                               ; preds = %14
  %39 = load i32, ptr %2, align 4, !tbaa !5
  %40 = load i32, ptr @tot, align 4, !tbaa !5
  %41 = add nsw i32 %40, 1
  store i32 %41, ptr @tot, align 4, !tbaa !5
  %42 = sext i32 %40 to i64
  %43 = getelementptr inbounds [2001 x i32], ptr @seq, i64 0, i64 %42
  store i32 %39, ptr %43, align 4, !tbaa !5
  ret void
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 = { 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 = !{!10, !10, i64 0}
!10 = !{!"bool", !7, i64 0}
!11 = !{!12, !6, i64 4}
!12 = !{!"_ZTS4Edge", !6, i64 0, !6, i64 4}
!13 = !{i8 0, i8 2}
!14 = !{}
!15 = !{!12, !6, i64 0}
!16 = distinct !{!16, !17}
!17 = !{!"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"

%struct.Edge = type { i32, i32 }

@tot = external dso_local local_unnamed_addr global i32, align 4
@pre = external dso_local local_unnamed_addr global [2001 x i32], align 16
@seq = external dso_local local_unnamed_addr global [2001 x i32], align 16
@vis = external dso_local local_unnamed_addr global [2001 x i8], align 16
@e = external dso_local local_unnamed_addr global [4000003 x %struct.Edge], align 16

; Function Attrs: mustprogress nofree nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: none) uwtable
define dso_local void @_Z4dfs1i(i32 noundef %0) local_unnamed_addr #0 {
  %2 = sext i32 %0 to i64
  %3 = getelementptr inbounds [2001 x i8], ptr @vis, i64 0, i64 %2
  store i8 1, ptr %3, align 1, !tbaa !5
  %4 = getelementptr inbounds [2001 x i32], ptr @pre, i64 0, i64 %2
  %.07 = load i32, ptr %4, align 4, !tbaa !9
  %.not8 = icmp eq i32 %.07, -1
  br i1 %.not8, label %._crit_edge, label %.lr.ph

._crit_edge:                                      ; preds = %18, %1
  %5 = load i32, ptr @tot, align 4, !tbaa !9
  %6 = add nsw i32 %5, 1
  store i32 %6, ptr @tot, align 4, !tbaa !9
  %7 = sext i32 %5 to i64
  %8 = getelementptr inbounds [2001 x i32], ptr @seq, i64 0, i64 %7
  store i32 %0, ptr %8, align 4, !tbaa !9
  ret void

.lr.ph:                                           ; preds = %1, %18
  %.09 = phi i32 [ %.0, %18 ], [ %.07, %1 ]
  %9 = sext i32 %.09 to i64
  %10 = getelementptr inbounds [4000003 x %struct.Edge], ptr @e, i64 0, i64 %9
  %11 = getelementptr inbounds i8, ptr %10, i64 4
  %12 = load i32, ptr %11, align 4, !tbaa !11
  %13 = sext i32 %12 to i64
  %14 = getelementptr inbounds [2001 x i8], ptr @vis, i64 0, i64 %13
  %15 = load i8, ptr %14, align 1, !tbaa !5, !range !13, !noundef !14
  %16 = trunc nuw i8 %15 to i1
  br i1 %16, label %18, label %17

17:                                               ; preds = %.lr.ph
  tail call void @_Z4dfs1i(i32 noundef %12)
  br label %18

18:                                               ; preds = %.lr.ph, %17
  %.0 = load i32, ptr %10, align 8, !tbaa !9
  %.not = icmp eq i32 %.0, -1
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !15
}

attributes #0 = { mustprogress nofree nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: none) 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 = !{!"bool", !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, !10, i64 4}
!12 = !{!"_ZTS4Edge", !10, i64 0, !10, i64 4}
!13 = !{i8 0, i8 2}
!14 = !{}
!15 = distinct !{!15, !16}
!16 = !{!"llvm.loop.mustprogress"}


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