; LLVM IR from Dev-XYS/Algorithms :: Depth-First-Search.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.vertex = type { i32, i32 }
%struct.edge = type { i32, i32 }

@V = external dso_local global [100000 x %struct.vertex], align 16
@latest = external dso_local global i32, align 4
@E = external dso_local global [100000 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 %2, align 4, !tbaa !5
  %5 = sext i32 %4 to i64
  %6 = getelementptr inbounds [100000 x %struct.vertex], ptr @V, i64 0, i64 %5
  %7 = getelementptr inbounds %struct.vertex, ptr %6, i32 0, i32 1
  %8 = load i32, ptr %7, align 4, !tbaa !9
  %9 = icmp eq i32 %8, 0
  br i1 %9, label %10, label %39

10:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  %11 = load i32, ptr %2, align 4, !tbaa !5
  %12 = sext i32 %11 to i64
  %13 = getelementptr inbounds [100000 x %struct.vertex], ptr @V, i64 0, i64 %12
  %14 = getelementptr inbounds %struct.vertex, ptr %13, i32 0, i32 0
  %15 = load i32, ptr %14, align 8, !tbaa !11
  store i32 %15, ptr %3, align 4, !tbaa !5
  br label %16

16:                                               ; preds = %26, %10
  %17 = load i32, ptr %3, align 4, !tbaa !5
  %18 = icmp ne i32 %17, 0
  br i1 %18, label %20, label %19

19:                                               ; preds = %16
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  br label %32

20:                                               ; preds = %16
  %21 = load i32, ptr %3, align 4, !tbaa !5
  %22 = sext i32 %21 to i64
  %23 = getelementptr inbounds [100000 x %struct.edge], ptr @E, i64 0, i64 %22
  %24 = getelementptr inbounds %struct.edge, ptr %23, i32 0, i32 0
  %25 = load i32, ptr %24, align 8, !tbaa !12
  call void @_Z3DFSi(i32 noundef %25)
  br label %26

26:                                               ; preds = %20
  %27 = load i32, ptr %3, align 4, !tbaa !5
  %28 = sext i32 %27 to i64
  %29 = getelementptr inbounds [100000 x %struct.edge], ptr @E, i64 0, i64 %28
  %30 = getelementptr inbounds %struct.edge, ptr %29, i32 0, i32 1
  %31 = load i32, ptr %30, align 4, !tbaa !14
  store i32 %31, ptr %3, align 4, !tbaa !5
  br label %16, !llvm.loop !15

32:                                               ; preds = %19
  %33 = load i32, ptr @latest, align 4, !tbaa !5
  %34 = add nsw i32 %33, 1
  store i32 %34, ptr @latest, align 4, !tbaa !5
  %35 = load i32, ptr %2, align 4, !tbaa !5
  %36 = sext i32 %35 to i64
  %37 = getelementptr inbounds [100000 x %struct.vertex], ptr @V, i64 0, i64 %36
  %38 = getelementptr inbounds %struct.vertex, ptr %37, i32 0, i32 1
  store i32 %33, ptr %38, align 4, !tbaa !9
  br label %39

39:                                               ; preds = %32, %1
  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 = !{!"_ZTS6vertex", !6, i64 0, !6, i64 4}
!11 = !{!10, !6, i64 0}
!12 = !{!13, !6, i64 0}
!13 = !{!"_ZTS4edge", !6, i64 0, !6, i64 4}
!14 = !{!13, !6, i64 4}
!15 = distinct !{!15, !16}
!16 = !{!"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.vertex = type { i32, i32 }
%struct.edge = type { i32, i32 }

@V = external dso_local local_unnamed_addr global [100000 x %struct.vertex], align 16
@latest = external dso_local local_unnamed_addr global i32, align 4
@E = external dso_local local_unnamed_addr global [100000 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 = sext i32 %0 to i64
  %3 = getelementptr inbounds [100000 x %struct.vertex], ptr @V, i64 0, i64 %2
  %4 = getelementptr inbounds i8, ptr %3, i64 4
  %5 = load i32, ptr %4, align 4, !tbaa !5
  %6 = icmp eq i32 %5, 0
  br i1 %6, label %.preheader, label %13

.preheader:                                       ; preds = %1
  %.06 = load i32, ptr %3, align 8, !tbaa !10
  %.not7 = icmp eq i32 %.06, 0
  br i1 %.not7, label %._crit_edge, label %.lr.ph

._crit_edge:                                      ; preds = %.lr.ph, %.preheader
  %7 = load i32, ptr @latest, align 4, !tbaa !10
  %8 = add nsw i32 %7, 1
  store i32 %8, ptr @latest, align 4, !tbaa !10
  store i32 %7, ptr %4, align 4, !tbaa !5
  br label %13

.lr.ph:                                           ; preds = %.preheader, %.lr.ph
  %.08 = phi i32 [ %.0, %.lr.ph ], [ %.06, %.preheader ]
  %9 = sext i32 %.08 to i64
  %10 = getelementptr inbounds [100000 x %struct.edge], ptr @E, i64 0, i64 %9
  %11 = load i32, ptr %10, align 8, !tbaa !11
  tail call void @_Z3DFSi(i32 noundef %11)
  %12 = getelementptr inbounds i8, ptr %10, i64 4
  %.0 = load i32, ptr %12, align 4, !tbaa !10
  %.not = icmp eq i32 %.0, 0
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !13

13:                                               ; preds = %._crit_edge, %1
  ret void
}

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, !7, i64 4}
!6 = !{!"_ZTS6vertex", !7, i64 0, !7, i64 4}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C++ TBAA"}
!10 = !{!7, !7, i64 0}
!11 = !{!12, !7, i64 0}
!12 = !{!"_ZTS4edge", !7, i64 0, !7, i64 4}
!13 = distinct !{!13, !14}
!14 = !{!"llvm.loop.mustprogress"}


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