; LLVM IR from HarshCasper/NeoAlgo :: C/ds (middle_element_of_linkedlist)

; 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"

@.str.1 = external hidden unnamed_addr constant [48 x i8], align 1
@.str.2 = external hidden unnamed_addr constant [3 x i8], align 1
@.str.3 = external hidden unnamed_addr constant [20 x i8], align 1

; Function Attrs: nounwind uwtable
declare dso_local void @detectMiddle(ptr noundef) #0

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

declare i32 @printf(ptr noundef, ...) #2

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

; Function Attrs: nounwind uwtable
declare dso_local void @push(ptr noundef, i32 noundef) #0

; Function Attrs: nounwind uwtable
define dso_local i32 @main() #0 {
  %1 = alloca i32, align 4
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  call void @llvm.lifetime.start.p0(i64 8, ptr %2) #3
  store ptr null, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #3
  %6 = call i32 (ptr, ...) @printf(ptr noundef @.str.1)
  %7 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str.2, ptr noundef %3)
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #3
  %8 = load i32, ptr %3, align 4, !tbaa !9
  store i32 %8, ptr %4, align 4, !tbaa !9
  br label %9

9:                                                ; preds = %17, %0
  %10 = load i32, ptr %4, align 4, !tbaa !9
  %11 = icmp sgt i32 %10, 0
  br i1 %11, label %13, label %12

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

13:                                               ; preds = %9
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  %14 = call i32 (ptr, ...) @printf(ptr noundef @.str.3)
  %15 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str.2, ptr noundef %5)
  %16 = load i32, ptr %5, align 4, !tbaa !9
  call void @push(ptr noundef %2, i32 noundef %16)
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  br label %17

17:                                               ; preds = %13
  %18 = load i32, ptr %4, align 4, !tbaa !9
  %19 = add nsw i32 %18, -1
  store i32 %19, ptr %4, align 4, !tbaa !9
  br label %9, !llvm.loop !11

20:                                               ; preds = %12
  %21 = load ptr, ptr %2, align 8, !tbaa !5
  call void @detectMiddle(ptr noundef %21)
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %2) #3
  ret i32 0
}

declare i32 @__isoc99_scanf(ptr noundef, ...) #2

attributes #0 = { 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 = { "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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"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"

@.str.1 = external hidden unnamed_addr constant [48 x i8], align 1
@.str.2 = external hidden unnamed_addr constant [3 x i8], align 1
@.str.3 = external hidden unnamed_addr constant [20 x i8], align 1

; Function Attrs: nounwind uwtable
declare dso_local void @detectMiddle(ptr noundef) local_unnamed_addr #0

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

; Function Attrs: nofree nounwind
declare noundef i32 @printf(ptr nocapture noundef readonly, ...) local_unnamed_addr #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: nounwind uwtable
declare dso_local void @push(ptr noundef, i32 noundef) local_unnamed_addr #0

; Function Attrs: nounwind uwtable
define dso_local noundef i32 @main() local_unnamed_addr #0 {
  %1 = alloca ptr, align 8
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 8, ptr nonnull %1) #3
  store ptr null, ptr %1, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %2) #3
  %4 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.1)
  %5 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str.2, ptr noundef nonnull %2)
  %6 = load i32, ptr %2, align 4, !tbaa !9
  %7 = icmp sgt i32 %6, 0
  br i1 %7, label %.lr.ph, label %._crit_edge

._crit_edge.loopexit:                             ; preds = %.lr.ph
  %.pre = load ptr, ptr %1, align 8, !tbaa !5
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %0
  %8 = phi ptr [ %.pre, %._crit_edge.loopexit ], [ null, %0 ]
  call void @detectMiddle(ptr noundef %8)
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %2) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr nonnull %1) #3
  ret i32 0

.lr.ph:                                           ; preds = %0, %.lr.ph
  %.02 = phi i32 [ %12, %.lr.ph ], [ %6, %0 ]
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %3) #3
  %9 = call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.3)
  %10 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str.2, ptr noundef nonnull %3)
  %11 = load i32, ptr %3, align 4, !tbaa !9
  call void @push(ptr noundef nonnull %1, i32 noundef %11)
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %3) #3
  %12 = add nsw i32 %.02, -1
  %13 = icmp ugt i32 %.02, 1
  br i1 %13, label %.lr.ph, label %._crit_edge.loopexit, !llvm.loop !11
}

; Function Attrs: nofree nounwind
declare noundef i32 @__isoc99_scanf(ptr nocapture noundef readonly, ...) local_unnamed_addr #2

attributes #0 = { 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 = { nofree nounwind "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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: CorrelatedValuePropagationPass,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass