; LLVM IR from bqi343/cp-notebook :: Contests/USACO Solutions/2017-18/Dec 2017/Silver/17 Dec Silver 3.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"

@a = external dso_local global [100001 x i32], align 16
@vis = external dso_local global [100001 x i32], align 16

; Function Attrs: mustprogress nounwind uwtable
define dso_local void @_Z3dfsi(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  %5 = load i32, ptr %2, align 4, !tbaa !5
  store i32 %5, ptr %3, align 4, !tbaa !5
  br label %6

6:                                                ; preds = %12, %1
  %7 = load i32, ptr %2, align 4, !tbaa !5
  %8 = sext i32 %7 to i64
  %9 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %8
  %10 = load i32, ptr %9, align 4, !tbaa !5
  %11 = icmp eq i32 %10, 0
  br i1 %11, label %12, label %21

12:                                               ; preds = %6
  %13 = load i32, ptr %3, align 4, !tbaa !5
  %14 = load i32, ptr %2, align 4, !tbaa !5
  %15 = sext i32 %14 to i64
  %16 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %15
  store i32 %13, ptr %16, align 4, !tbaa !5
  %17 = load i32, ptr %2, align 4, !tbaa !5
  %18 = sext i32 %17 to i64
  %19 = getelementptr inbounds [100001 x i32], ptr @a, i64 0, i64 %18
  %20 = load i32, ptr %19, align 4, !tbaa !5
  store i32 %20, ptr %2, align 4, !tbaa !5
  br label %6, !llvm.loop !9

21:                                               ; preds = %6
  %22 = load i32, ptr %2, align 4, !tbaa !5
  %23 = sext i32 %22 to i64
  %24 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %23
  %25 = load i32, ptr %24, align 4, !tbaa !5
  %26 = load i32, ptr %3, align 4, !tbaa !5
  %27 = icmp ne i32 %25, %26
  br i1 %27, label %28, label %29

28:                                               ; preds = %21
  store i32 1, ptr %4, align 4
  br label %45

29:                                               ; preds = %21
  br label %30

30:                                               ; preds = %36, %29
  %31 = load i32, ptr %2, align 4, !tbaa !5
  %32 = sext i32 %31 to i64
  %33 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %32
  %34 = load i32, ptr %33, align 4, !tbaa !5
  %35 = icmp ne i32 %34, -1
  br i1 %35, label %36, label %44

36:                                               ; preds = %30
  %37 = load i32, ptr %2, align 4, !tbaa !5
  %38 = sext i32 %37 to i64
  %39 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %38
  store i32 -1, ptr %39, align 4, !tbaa !5
  %40 = load i32, ptr %2, align 4, !tbaa !5
  %41 = sext i32 %40 to i64
  %42 = getelementptr inbounds [100001 x i32], ptr @a, i64 0, i64 %41
  %43 = load i32, ptr %42, align 4, !tbaa !5
  store i32 %43, ptr %2, align 4, !tbaa !5
  br label %30, !llvm.loop !11

44:                                               ; preds = %30
  store i32 0, ptr %4, align 4
  br label %45

45:                                               ; preds = %44, %28
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  %46 = load i32, ptr %4, align 4
  switch i32 %46, label %48 [
    i32 0, label %47
    i32 1, label %47
  ]

47:                                               ; preds = %45, %45
  ret void

48:                                               ; preds = %45
  unreachable
}

; 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 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 = { 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 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}
!11 = distinct !{!11, !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"

@a = external dso_local local_unnamed_addr global [100001 x i32], align 16
@vis = external dso_local local_unnamed_addr global [100001 x i32], align 16

; Function Attrs: mustprogress nofree norecurse nosync nounwind memory(readwrite, argmem: write, inaccessiblemem: none) uwtable
define dso_local void @_Z3dfsi(i32 noundef %0) local_unnamed_addr #0 {
  %2 = sext i32 %0 to i64
  %3 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %2
  %4 = load i32, ptr %3, align 4, !tbaa !5
  %5 = icmp eq i32 %4, 0
  br i1 %5, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %1, %.lr.ph
  %6 = phi ptr [ %11, %.lr.ph ], [ %3, %1 ]
  %7 = phi i64 [ %10, %.lr.ph ], [ %2, %1 ]
  store i32 %0, ptr %6, align 4, !tbaa !5
  %8 = getelementptr inbounds [100001 x i32], ptr @a, i64 0, i64 %7
  %9 = load i32, ptr %8, align 4, !tbaa !5
  %10 = sext i32 %9 to i64
  %11 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %10
  %12 = load i32, ptr %11, align 4, !tbaa !5
  %13 = icmp eq i32 %12, 0
  br i1 %13, label %.lr.ph, label %._crit_edge, !llvm.loop !9

._crit_edge:                                      ; preds = %.lr.ph, %1
  %.0.lcssa = phi i32 [ %0, %1 ], [ %9, %.lr.ph ]
  %14 = phi i32 [ %4, %1 ], [ %12, %.lr.ph ]
  %.not = icmp ne i32 %14, %0
  %.not1113 = icmp eq i32 %0, -1
  %or.cond = or i1 %.not, %.not1113
  br i1 %or.cond, label %.loopexit, label %.lr.ph14.preheader

.lr.ph14.preheader:                               ; preds = %._crit_edge
  %15 = sext i32 %.0.lcssa to i64
  %16 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %15
  br label %.lr.ph14

.lr.ph14:                                         ; preds = %.lr.ph14.preheader, %.lr.ph14
  %17 = phi ptr [ %22, %.lr.ph14 ], [ %16, %.lr.ph14.preheader ]
  %18 = phi i64 [ %21, %.lr.ph14 ], [ %15, %.lr.ph14.preheader ]
  store i32 -1, ptr %17, align 4, !tbaa !5
  %19 = getelementptr inbounds [100001 x i32], ptr @a, i64 0, i64 %18
  %20 = load i32, ptr %19, align 4, !tbaa !5
  %21 = sext i32 %20 to i64
  %22 = getelementptr inbounds [100001 x i32], ptr @vis, i64 0, i64 %21
  %23 = load i32, ptr %22, align 4, !tbaa !5
  %.not11 = icmp eq i32 %23, -1
  br i1 %.not11, label %.loopexit, label %.lr.ph14, !llvm.loop !11

.loopexit:                                        ; preds = %.lr.ph14, %._crit_edge
  ret void
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind memory(readwrite, argmem: write, 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 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}
!11 = distinct !{!11, !10}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass