; LLVM IR from sunkafei/xcpc-algorithm-templates :: 算法/图论/无向图的点双连通分量.ll (Z8find_bcci)

; 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::vector" = type { %"struct.std::_Vector_base" }
%"struct.std::_Vector_base" = type { %"struct.std::_Vector_base<int, std::allocator<int>>::_Vector_impl" }
%"struct.std::_Vector_base<int, std::allocator<int>>::_Vector_impl" = type { %"struct.std::_Vector_base<int, std::allocator<int>>::_Vector_impl_data" }
%"struct.std::_Vector_base<int, std::allocator<int>>::_Vector_impl_data" = type { ptr, ptr, ptr }
%"class.std::stack" = type { %"class.std::deque" }
%"class.std::deque" = type { %"class.std::_Deque_base" }
%"class.std::_Deque_base" = type { %"struct.std::_Deque_base<int, std::allocator<int>>::_Deque_impl" }
%"struct.std::_Deque_base<int, std::allocator<int>>::_Deque_impl" = type { %"struct.std::_Deque_base<int, std::allocator<int>>::_Deque_impl_data" }
%"struct.std::_Deque_base<int, std::allocator<int>>::_Deque_impl_data" = type { ptr, i64, %"struct.std::_Deque_iterator", %"struct.std::_Deque_iterator" }
%"struct.std::_Deque_iterator" = type { ptr, ptr, ptr, ptr }

@bcc = external dso_local global [510000 x %"class.std::vector"], align 16
@S = external dso_local global %"class.std::stack", align 8
@pre = external dso_local global [510000 x i32], align 16
@dfs_clock = external dso_local global i32, align 4
@bcc_cnt = external dso_local global i32, align 4

; Function Attrs: mustprogress uwtable
declare dso_local noundef i32 @_Z3dfsii(i32 noundef, i32 noundef) #0

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

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZNSt5stackIiSt5dequeIiSaIiEEE3popEv(ptr noundef nonnull align 8 dereferenceable(80)) #2 align 2

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

; Function Attrs: mustprogress uwtable
define dso_local void @_Z8find_bcci(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) #3
  store i32 0, ptr %3, align 4, !tbaa !5
  br label %5

5:                                                ; preds = %17, %1
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = load i32, ptr %2, align 4, !tbaa !5
  %8 = icmp sle i32 %6, %7
  br i1 %8, label %10, label %9

9:                                                ; preds = %5
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  br label %20

10:                                               ; preds = %5
  %11 = load i32, ptr %3, align 4, !tbaa !5
  %12 = sext i32 %11 to i64
  %13 = getelementptr inbounds [510000 x i32], ptr @pre, i64 0, i64 %12
  store i32 0, ptr %13, align 4, !tbaa !5
  %14 = load i32, ptr %3, align 4, !tbaa !5
  %15 = sext i32 %14 to i64
  %16 = getelementptr inbounds [510000 x %"class.std::vector"], ptr @bcc, i64 0, i64 %15
  call void @_ZNSt6vectorIiSaIiEE5clearEv(ptr noundef nonnull align 8 dereferenceable(24) %16) #3
  br label %17

17:                                               ; preds = %10
  %18 = load i32, ptr %3, align 4, !tbaa !5
  %19 = add nsw i32 %18, 1
  store i32 %19, ptr %3, align 4, !tbaa !5
  br label %5, !llvm.loop !9

20:                                               ; preds = %9
  br label %21

21:                                               ; preds = %24, %20
  %22 = call noundef i64 @_ZNKSt5stackIiSt5dequeIiSaIiEEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(80) @S)
  %23 = icmp ne i64 %22, 0
  br i1 %23, label %24, label %25

24:                                               ; preds = %21
  call void @_ZNSt5stackIiSt5dequeIiSaIiEEE3popEv(ptr noundef nonnull align 8 dereferenceable(80) @S)
  br label %21, !llvm.loop !11

25:                                               ; preds = %21
  store i32 0, ptr @bcc_cnt, align 4, !tbaa !5
  store i32 0, ptr @dfs_clock, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #3
  store i32 1, ptr %4, align 4, !tbaa !5
  br label %26

26:                                               ; preds = %41, %25
  %27 = load i32, ptr %4, align 4, !tbaa !5
  %28 = load i32, ptr %2, align 4, !tbaa !5
  %29 = icmp sle i32 %27, %28
  br i1 %29, label %31, label %30

30:                                               ; preds = %26
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #3
  br label %44

31:                                               ; preds = %26
  %32 = load i32, ptr %4, align 4, !tbaa !5
  %33 = sext i32 %32 to i64
  %34 = getelementptr inbounds [510000 x i32], ptr @pre, i64 0, i64 %33
  %35 = load i32, ptr %34, align 4, !tbaa !5
  %36 = icmp ne i32 %35, 0
  br i1 %36, label %40, label %37

37:                                               ; preds = %31
  %38 = load i32, ptr %4, align 4, !tbaa !5
  %39 = call noundef i32 @_Z3dfsii(i32 noundef %38, i32 noundef -1)
  br label %40

40:                                               ; preds = %37, %31
  br label %41

41:                                               ; preds = %40
  %42 = load i32, ptr %4, align 4, !tbaa !5
  %43 = add nsw i32 %42, 1
  store i32 %43, ptr %4, align 4, !tbaa !5
  br label %26, !llvm.loop !12

44:                                               ; preds = %30
  ret void
}

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZNSt6vectorIiSaIiEE5clearEv(ptr noundef nonnull align 8 dereferenceable(24)) #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef i64 @_ZNKSt5stackIiSt5dequeIiSaIiEEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(80)) #2 align 2

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 = { 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 #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"}
!11 = distinct !{!11, !10}
!12 = distinct !{!12, !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"

%"class.std::vector" = type { %"struct.std::_Vector_base" }
%"struct.std::_Vector_base" = type { %"struct.std::_Vector_base<int, std::allocator<int>>::_Vector_impl" }
%"struct.std::_Vector_base<int, std::allocator<int>>::_Vector_impl" = type { %"struct.std::_Vector_base<int, std::allocator<int>>::_Vector_impl_data" }
%"struct.std::_Vector_base<int, std::allocator<int>>::_Vector_impl_data" = type { ptr, ptr, ptr }
%"class.std::stack" = type { %"class.std::deque" }
%"class.std::deque" = type { %"class.std::_Deque_base" }
%"class.std::_Deque_base" = type { %"struct.std::_Deque_base<int, std::allocator<int>>::_Deque_impl" }
%"struct.std::_Deque_base<int, std::allocator<int>>::_Deque_impl" = type { %"struct.std::_Deque_base<int, std::allocator<int>>::_Deque_impl_data" }
%"struct.std::_Deque_base<int, std::allocator<int>>::_Deque_impl_data" = type { ptr, i64, %"struct.std::_Deque_iterator", %"struct.std::_Deque_iterator" }
%"struct.std::_Deque_iterator" = type { ptr, ptr, ptr, ptr }

@bcc = external dso_local global [510000 x %"class.std::vector"], align 16
@S = external dso_local global %"class.std::stack", align 8
@pre = external dso_local local_unnamed_addr global [510000 x i32], align 16
@dfs_clock = external dso_local local_unnamed_addr global i32, align 4
@bcc_cnt = external dso_local local_unnamed_addr global i32, align 4

; Function Attrs: mustprogress uwtable
declare dso_local noundef i32 @_Z3dfsii(i32 noundef, i32 noundef) local_unnamed_addr #0

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZNSt5stackIiSt5dequeIiSaIiEEE3popEv(ptr noundef nonnull align 8 dereferenceable(80)) local_unnamed_addr #1 align 2

; Function Attrs: mustprogress uwtable
define dso_local void @_Z8find_bcci(i32 noundef %0) local_unnamed_addr #0 {
  %.not15 = icmp slt i32 %0, 0
  br i1 %.not15, label %.preheader, label %.lr.ph.preheader

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

.preheader:                                       ; preds = %.lr.ph, %1
  %3 = tail call noundef i64 @_ZNKSt5stackIiSt5dequeIiSaIiEEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(80) @S)
  %.not1217 = icmp eq i64 %3, 0
  br i1 %.not1217, label %._crit_edge, label %.lr.ph18

.lr.ph:                                           ; preds = %.lr.ph.preheader, %.lr.ph
  %indvars.iv = phi i64 [ 0, %.lr.ph.preheader ], [ %indvars.iv.next, %.lr.ph ]
  %4 = getelementptr inbounds [510000 x i32], ptr @pre, i64 0, i64 %indvars.iv
  store i32 0, ptr %4, align 4, !tbaa !5
  %5 = getelementptr inbounds [510000 x %"class.std::vector"], ptr @bcc, i64 0, i64 %indvars.iv
  tail call void @_ZNSt6vectorIiSaIiEE5clearEv(ptr noundef nonnull align 8 dereferenceable(24) %5) #2
  %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 %.preheader, label %.lr.ph, !llvm.loop !9

.lr.ph18:                                         ; preds = %.preheader, %.lr.ph18
  tail call void @_ZNSt5stackIiSt5dequeIiSaIiEEE3popEv(ptr noundef nonnull align 8 dereferenceable(80) @S)
  %6 = tail call noundef i64 @_ZNKSt5stackIiSt5dequeIiSaIiEEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(80) @S)
  %.not12 = icmp eq i64 %6, 0
  br i1 %.not12, label %._crit_edge, label %.lr.ph18, !llvm.loop !11

._crit_edge:                                      ; preds = %.lr.ph18, %.preheader
  store i32 0, ptr @bcc_cnt, align 4, !tbaa !5
  store i32 0, ptr @dfs_clock, align 4, !tbaa !5
  %.not1319 = icmp slt i32 %0, 1
  br i1 %.not1319, label %._crit_edge23, label %.lr.ph22.preheader

.lr.ph22.preheader:                               ; preds = %._crit_edge
  %7 = add nuw i32 %0, 1
  %wide.trip.count28 = zext i32 %7 to i64
  br label %.lr.ph22

._crit_edge23:                                    ; preds = %13, %._crit_edge
  ret void

.lr.ph22:                                         ; preds = %.lr.ph22.preheader, %13
  %indvars.iv25 = phi i64 [ 1, %.lr.ph22.preheader ], [ %indvars.iv.next26, %13 ]
  %8 = getelementptr inbounds [510000 x i32], ptr @pre, i64 0, i64 %indvars.iv25
  %9 = load i32, ptr %8, align 4, !tbaa !5
  %.not14 = icmp eq i32 %9, 0
  br i1 %.not14, label %10, label %13

10:                                               ; preds = %.lr.ph22
  %11 = trunc nuw nsw i64 %indvars.iv25 to i32
  %12 = tail call noundef i32 @_Z3dfsii(i32 noundef %11, i32 noundef -1)
  br label %13

13:                                               ; preds = %.lr.ph22, %10
  %indvars.iv.next26 = add nuw nsw i64 %indvars.iv25, 1
  %exitcond29.not = icmp eq i64 %indvars.iv.next26, %wide.trip.count28
  br i1 %exitcond29.not, label %._crit_edge23, label %.lr.ph22, !llvm.loop !12
}

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZNSt6vectorIiSaIiEE5clearEv(ptr noundef nonnull align 8 dereferenceable(24)) local_unnamed_addr #1 align 2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef i64 @_ZNKSt5stackIiSt5dequeIiSaIiEEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(80)) local_unnamed_addr #1 align 2

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 = { 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 #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}
!12 = distinct !{!12, !10}


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