; LLVM IR from tangjz/acm-icpc :: hdu/6072.ll (Z4dfs2i)

; 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.Bitset = type { [4 x i64] }

@n = external dso_local global i32, align 4
@tot = external dso_local global i32, align 4
@g = external dso_local global [251 x %struct.Bitset], align 16
@cur = external dso_local global %struct.Bitset, align 8

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZN6Bitset4flipEi(ptr noundef nonnull align 8 dereferenceable(32), i32 noundef) #0 align 2

; 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 @_ZNK6BitsetmiERKS_(ptr dead_on_unwind noalias writable sret(%struct.Bitset) align 8, ptr noundef nonnull align 8 dereferenceable(32), ptr noundef nonnull align 8 dereferenceable(32)) #0 align 2

; Function Attrs: mustprogress uwtable
declare dso_local noundef i32 @_ZNK6Bitset6lowbitEv(ptr noundef nonnull align 8 dereferenceable(32)) #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 @_Z4dfs2i(i32 noundef %0) #2 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca %struct.Bitset, align 8
  %5 = alloca %struct.Bitset, align 8
  store i32 %0, ptr %2, align 4, !tbaa !5
  %6 = load i32, ptr @tot, align 4, !tbaa !5
  %7 = add nsw i32 %6, 1
  store i32 %7, ptr @tot, align 4, !tbaa !5
  %8 = load i32, ptr %2, align 4, !tbaa !5
  call void @_ZN6Bitset4flipEi(ptr noundef nonnull align 8 dereferenceable(32) @cur, i32 noundef %8)
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #3
  call void @llvm.lifetime.start.p0(i64 32, ptr %4) #3
  %9 = load i32, ptr %2, align 4, !tbaa !5
  %10 = sext i32 %9 to i64
  %11 = getelementptr inbounds [251 x %struct.Bitset], ptr @g, i64 0, i64 %10
  call void @_ZNK6BitsetmiERKS_(ptr dead_on_unwind writable sret(%struct.Bitset) align 8 %4, ptr noundef nonnull align 8 dereferenceable(32) %11, ptr noundef nonnull align 8 dereferenceable(32) @cur)
  %12 = call noundef i32 @_ZNK6Bitset6lowbitEv(ptr noundef nonnull align 8 dereferenceable(32) %4)
  call void @llvm.lifetime.end.p0(i64 32, ptr %4) #3
  store i32 %12, ptr %3, align 4, !tbaa !5
  br label %13

13:                                               ; preds = %20, %1
  %14 = load i32, ptr %3, align 4, !tbaa !5
  %15 = load i32, ptr @n, align 4, !tbaa !5
  %16 = icmp slt i32 %14, %15
  br i1 %16, label %18, label %17

17:                                               ; preds = %13
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  br label %25

18:                                               ; preds = %13
  %19 = load i32, ptr %3, align 4, !tbaa !5
  call void @_Z4dfs2i(i32 noundef %19)
  br label %20

20:                                               ; preds = %18
  call void @llvm.lifetime.start.p0(i64 32, ptr %5) #3
  %21 = load i32, ptr %2, align 4, !tbaa !5
  %22 = sext i32 %21 to i64
  %23 = getelementptr inbounds [251 x %struct.Bitset], ptr @g, i64 0, i64 %22
  call void @_ZNK6BitsetmiERKS_(ptr dead_on_unwind writable sret(%struct.Bitset) align 8 %5, ptr noundef nonnull align 8 dereferenceable(32) %23, ptr noundef nonnull align 8 dereferenceable(32) @cur)
  %24 = call noundef i32 @_ZNK6Bitset6lowbitEv(ptr noundef nonnull align 8 dereferenceable(32) %5)
  store i32 %24, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 32, ptr %5) #3
  br label %13, !llvm.loop !9

25:                                               ; preds = %17
  ret void
}

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 = { 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 #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"

%struct.Bitset = type { [4 x i64] }

@n = external dso_local local_unnamed_addr global i32, align 4
@tot = external dso_local local_unnamed_addr global i32, align 4
@g = external dso_local global [251 x %struct.Bitset], align 16
@cur = external dso_local global %struct.Bitset, align 8

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZN6Bitset4flipEi(ptr noundef nonnull align 8 dereferenceable(32), i32 noundef) local_unnamed_addr #0 align 2

; Function Attrs: mustprogress 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 @_ZNK6BitsetmiERKS_(ptr dead_on_unwind noalias writable sret(%struct.Bitset) align 8, ptr noundef nonnull align 8 dereferenceable(32), ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #0 align 2

; Function Attrs: mustprogress uwtable
declare dso_local noundef i32 @_ZNK6Bitset6lowbitEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #2 align 2

; Function Attrs: mustprogress 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 @_Z4dfs2i(i32 noundef %0) local_unnamed_addr #2 {
  %2 = alloca %struct.Bitset, align 8
  %3 = alloca %struct.Bitset, align 8
  %4 = load i32, ptr @tot, align 4, !tbaa !5
  %5 = add nsw i32 %4, 1
  store i32 %5, ptr @tot, align 4, !tbaa !5
  tail call void @_ZN6Bitset4flipEi(ptr noundef nonnull align 8 dereferenceable(32) @cur, i32 noundef %0)
  call void @llvm.lifetime.start.p0(i64 32, ptr nonnull %2) #3
  %6 = sext i32 %0 to i64
  %7 = getelementptr inbounds [251 x %struct.Bitset], ptr @g, i64 0, i64 %6
  call void @_ZNK6BitsetmiERKS_(ptr dead_on_unwind nonnull writable sret(%struct.Bitset) align 8 %2, ptr noundef nonnull align 8 dereferenceable(32) %7, ptr noundef nonnull align 8 dereferenceable(32) @cur)
  %8 = call noundef i32 @_ZNK6Bitset6lowbitEv(ptr noundef nonnull align 8 dereferenceable(32) %2)
  call void @llvm.lifetime.end.p0(i64 32, ptr nonnull %2) #3
  %9 = load i32, ptr @n, align 4, !tbaa !5
  %10 = icmp slt i32 %8, %9
  br i1 %10, label %.lr.ph, label %._crit_edge

._crit_edge:                                      ; preds = %.lr.ph, %1
  ret void

.lr.ph:                                           ; preds = %1, %.lr.ph
  %.05 = phi i32 [ %11, %.lr.ph ], [ %8, %1 ]
  call void @_Z4dfs2i(i32 noundef %.05)
  call void @llvm.lifetime.start.p0(i64 32, ptr nonnull %3) #3
  call void @_ZNK6BitsetmiERKS_(ptr dead_on_unwind nonnull writable sret(%struct.Bitset) align 8 %3, ptr noundef nonnull align 8 dereferenceable(32) %7, ptr noundef nonnull align 8 dereferenceable(32) @cur)
  %11 = call noundef i32 @_ZNK6Bitset6lowbitEv(ptr noundef nonnull align 8 dereferenceable(32) %3)
  call void @llvm.lifetime.end.p0(i64 32, ptr nonnull %3) #3
  %12 = load i32, ptr @n, align 4, !tbaa !5
  %13 = icmp slt i32 %11, %12
  br i1 %13, label %.lr.ph, label %._crit_edge, !llvm.loop !9
}

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 = { mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { 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 #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"}


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