; LLVM IR from eyangch/competitive-programming :: BOI/2006/countries.ll (Z3dfsx)

; 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"

@graph = external dso_local global [1000 x i64], align 16
@c = external dso_local global [1000 x i8], align 16

; Function Attrs: mustprogress uwtable
define dso_local noundef i64 @_Z3dfsx(i64 noundef %0) #0 {
  %2 = alloca i64, align 8
  store i64 %0, ptr %2, align 8, !tbaa !5
  %3 = load i64, ptr %2, align 8, !tbaa !5
  %4 = getelementptr inbounds [1000 x i8], ptr @c, i64 0, i64 %3
  %5 = load i8, ptr %4, align 1, !tbaa !9
  %6 = icmp ne i8 %5, 0
  br i1 %6, label %7, label %9

7:                                                ; preds = %1
  %8 = load i64, ptr %2, align 8, !tbaa !5
  br label %14

9:                                                ; preds = %1
  %10 = load i64, ptr %2, align 8, !tbaa !5
  %11 = getelementptr inbounds [1000 x i64], ptr @graph, i64 0, i64 %10
  %12 = load i64, ptr %11, align 8, !tbaa !5
  %13 = call noundef i64 @_Z3dfsx(i64 noundef %12)
  br label %14

14:                                               ; preds = %9, %7
  %15 = phi i64 [ %8, %7 ], [ %13, %9 ]
  ret i64 %15
}

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" }

!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 = !{!"long long", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!7, !7, i64 0}


; 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"

@graph = external dso_local local_unnamed_addr global [1000 x i64], align 16
@c = external dso_local local_unnamed_addr global [1000 x i8], align 16

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(read, argmem: none, inaccessiblemem: none) uwtable
define dso_local noundef i64 @_Z3dfsx(i64 noundef %0) local_unnamed_addr #0 {
  %2 = getelementptr inbounds [1000 x i8], ptr @c, i64 0, i64 %0
  %3 = load i8, ptr %2, align 1, !tbaa !5
  %.not3 = icmp eq i8 %3, 0
  br i1 %.not3, label %tailrecurse, label %tailrecurse._crit_edge

tailrecurse:                                      ; preds = %1, %tailrecurse
  %.tr4 = phi i64 [ %5, %tailrecurse ], [ %0, %1 ]
  %4 = getelementptr inbounds [1000 x i64], ptr @graph, i64 0, i64 %.tr4
  %5 = load i64, ptr %4, align 8, !tbaa !8
  %6 = getelementptr inbounds [1000 x i8], ptr @c, i64 0, i64 %5
  %7 = load i8, ptr %6, align 1, !tbaa !5
  %.not = icmp eq i8 %7, 0
  br i1 %.not, label %tailrecurse, label %tailrecurse._crit_edge

tailrecurse._crit_edge:                           ; preds = %tailrecurse, %1
  %.tr.lcssa = phi i64 [ %0, %1 ], [ %5, %tailrecurse ]
  ret i64 %.tr.lcssa
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(read, 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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C++ TBAA"}
!8 = !{!9, !9, i64 0}
!9 = !{!"long long", !6, i64 0}


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