; LLVM IR from tangjz/acm-icpc :: codeforces/gym/100827I.ll (Z3dfsi)

; 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
@lnk = external dso_local global [1000001 x i32], align 16
@in = external dso_local global [1000001 x i32], align 16
@out = external dso_local global [1000001 x i32], align 16
@e = external dso_local global [2000002 x %struct.Edge], align 16

; Function Attrs: mustprogress uwtable
define dso_local void @_Z3dfsi(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  %4 = load i32, ptr @tot, align 4, !tbaa !5
  %5 = add nsw i32 %4, 1
  store i32 %5, ptr @tot, align 4, !tbaa !5
  %6 = load i32, ptr %2, align 4, !tbaa !5
  %7 = sext i32 %6 to i64
  %8 = getelementptr inbounds [1000001 x i32], ptr @in, i64 0, i64 %7
  store i32 %5, ptr %8, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  %9 = load i32, ptr %2, align 4, !tbaa !5
  %10 = sext i32 %9 to i64
  %11 = getelementptr inbounds [1000001 x i32], ptr @lnk, i64 0, i64 %10
  %12 = load i32, ptr %11, align 4, !tbaa !5
  store i32 %12, ptr %3, align 4, !tbaa !5
  br label %13

13:                                               ; preds = %23, %1
  %14 = load i32, ptr %3, align 4, !tbaa !5
  %15 = icmp ne i32 %14, -1
  br i1 %15, label %17, label %16

16:                                               ; preds = %13
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  br label %29

17:                                               ; preds = %13
  %18 = load i32, ptr %3, align 4, !tbaa !5
  %19 = sext i32 %18 to i64
  %20 = getelementptr inbounds [2000002 x %struct.Edge], ptr @e, i64 0, i64 %19
  %21 = getelementptr inbounds %struct.Edge, ptr %20, i32 0, i32 1
  %22 = load i32, ptr %21, align 4, !tbaa !9
  call void @_Z3dfsi(i32 noundef %22)
  br label %23

23:                                               ; preds = %17
  %24 = load i32, ptr %3, align 4, !tbaa !5
  %25 = sext i32 %24 to i64
  %26 = getelementptr inbounds [2000002 x %struct.Edge], ptr @e, i64 0, i64 %25
  %27 = getelementptr inbounds %struct.Edge, ptr %26, i32 0, i32 0
  %28 = load i32, ptr %27, align 8, !tbaa !11
  store i32 %28, ptr %3, align 4, !tbaa !5
  br label %13, !llvm.loop !12

29:                                               ; preds = %16
  %30 = load i32, ptr @tot, align 4, !tbaa !5
  %31 = load i32, ptr %2, align 4, !tbaa !5
  %32 = sext i32 %31 to i64
  %33 = getelementptr inbounds [1000001 x i32], ptr @out, i64 0, i64 %32
  store i32 %30, ptr %33, align 4, !tbaa !5
  ret void
}

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

; 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 = { 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, !6, i64 4}
!10 = !{!"_ZTS4Edge", !6, i64 0, !6, i64 4}
!11 = !{!10, !6, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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
@lnk = external dso_local local_unnamed_addr global [1000001 x i32], align 16
@in = external dso_local local_unnamed_addr global [1000001 x i32], align 16
@out = external dso_local local_unnamed_addr global [1000001 x i32], align 16
@e = external dso_local local_unnamed_addr global [2000002 x %struct.Edge], align 16

; Function Attrs: mustprogress nofree nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: none) uwtable
define dso_local void @_Z3dfsi(i32 noundef %0) local_unnamed_addr #0 {
  %2 = load i32, ptr @tot, align 4, !tbaa !5
  %3 = add nsw i32 %2, 1
  store i32 %3, ptr @tot, align 4, !tbaa !5
  %4 = sext i32 %0 to i64
  %5 = getelementptr inbounds [1000001 x i32], ptr @in, i64 0, i64 %4
  store i32 %3, ptr %5, align 4, !tbaa !5
  %6 = getelementptr inbounds [1000001 x i32], ptr @lnk, i64 0, i64 %4
  %.06 = load i32, ptr %6, align 4, !tbaa !5
  %.not7 = icmp eq i32 %.06, -1
  br i1 %.not7, label %._crit_edge, label %.lr.ph

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

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %1
  %7 = phi i32 [ %.pre, %._crit_edge.loopexit ], [ %3, %1 ]
  %8 = getelementptr inbounds [1000001 x i32], ptr @out, i64 0, i64 %4
  store i32 %7, ptr %8, align 4, !tbaa !5
  ret void

.lr.ph:                                           ; preds = %1, %.lr.ph
  %.08 = phi i32 [ %.0, %.lr.ph ], [ %.06, %1 ]
  %9 = sext i32 %.08 to i64
  %10 = getelementptr inbounds [2000002 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 !9
  tail call void @_Z3dfsi(i32 noundef %12)
  %.0 = load i32, ptr %10, align 8, !tbaa !5
  %.not = icmp eq i32 %.0, -1
  br i1 %.not, label %._crit_edge.loopexit, label %.lr.ph, !llvm.loop !11
}

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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !6, i64 4}
!10 = !{!"_ZTS4Edge", !6, i64 0, !6, i64 4}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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