; LLVM IR from tangjz/acm-icpc :: self_training/2015-02-15/A.ll (Z3dfsii)

; 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"

@ans = external dso_local global i32, align 4

; Function Attrs: mustprogress uwtable
define dso_local void @_Z3dfsii(i32 noundef %0, i32 noundef %1) #0 {
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !5
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = load i32, ptr %4, align 4, !tbaa !5
  %8 = icmp eq i32 %6, %7
  br i1 %8, label %9, label %10

9:                                                ; preds = %2
  br label %31

10:                                               ; preds = %2
  %11 = load i32, ptr %4, align 4, !tbaa !5
  %12 = load i32, ptr %3, align 4, !tbaa !5
  %13 = sub nsw i32 %11, %12
  %14 = icmp eq i32 %13, 1
  br i1 %14, label %15, label %21

15:                                               ; preds = %10
  %16 = load i32, ptr %3, align 4, !tbaa !5
  %17 = load i32, ptr %4, align 4, !tbaa !5
  %18 = mul nsw i32 %16, %17
  %19 = load i32, ptr @ans, align 4, !tbaa !5
  %20 = add nsw i32 %19, %18
  store i32 %20, ptr @ans, align 4, !tbaa !5
  br label %21

21:                                               ; preds = %15, %10
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  %22 = load i32, ptr %3, align 4, !tbaa !5
  %23 = load i32, ptr %4, align 4, !tbaa !5
  %24 = add nsw i32 %22, %23
  %25 = ashr i32 %24, 1
  store i32 %25, ptr %5, align 4, !tbaa !5
  %26 = load i32, ptr %3, align 4, !tbaa !5
  %27 = load i32, ptr %5, align 4, !tbaa !5
  call void @_Z3dfsii(i32 noundef %26, i32 noundef %27)
  %28 = load i32, ptr %5, align 4, !tbaa !5
  %29 = add nsw i32 %28, 1
  %30 = load i32, ptr %4, align 4, !tbaa !5
  call void @_Z3dfsii(i32 noundef %29, i32 noundef %30)
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  br label %31

31:                                               ; preds = %21, %9
  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"}


; 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"

@ans = external dso_local local_unnamed_addr global i32, align 4

; Function Attrs: mustprogress nofree nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: none) uwtable
define dso_local void @_Z3dfsii(i32 noundef %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = icmp eq i32 %0, %1
  br i1 %3, label %tailrecurse._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %2, %tailrecurse
  %.tr14 = phi i32 [ %12, %tailrecurse ], [ %0, %2 ]
  %4 = sub nsw i32 %1, %.tr14
  %5 = icmp eq i32 %4, 1
  br i1 %5, label %6, label %tailrecurse

6:                                                ; preds = %.lr.ph
  %7 = mul nsw i32 %.tr14, %1
  %8 = load i32, ptr @ans, align 4, !tbaa !5
  %9 = add nsw i32 %8, %7
  store i32 %9, ptr @ans, align 4, !tbaa !5
  br label %tailrecurse

tailrecurse:                                      ; preds = %6, %.lr.ph
  %10 = add nsw i32 %.tr14, %1
  %11 = ashr i32 %10, 1
  tail call void @_Z3dfsii(i32 noundef %.tr14, i32 noundef %11)
  %12 = add nsw i32 %11, 1
  %13 = icmp eq i32 %12, %1
  br i1 %13, label %tailrecurse._crit_edge, label %.lr.ph

tailrecurse._crit_edge:                           ; preds = %tailrecurse, %2
  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, !6, i64 0}
!6 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}


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