; LLVM IR from Hunterdii/GeeksforGeeks-POTD :: February 2025 GFG SOLUTION (February-05)

; 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.Queue = type { ptr, ptr }
%struct.QueueNode = type { ptr, ptr }

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind uwtable
define dso_local ptr @dequeue(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %6 = load ptr, ptr %3, align 8, !tbaa !5
  %7 = getelementptr inbounds %struct.Queue, ptr %6, i32 0, i32 0
  %8 = load ptr, ptr %7, align 8, !tbaa !9
  %9 = icmp eq ptr %8, null
  br i1 %9, label %10, label %11

10:                                               ; preds = %1
  store ptr null, ptr %2, align 8
  br label %35

11:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  %12 = load ptr, ptr %3, align 8, !tbaa !5
  %13 = getelementptr inbounds %struct.Queue, ptr %12, i32 0, i32 0
  %14 = load ptr, ptr %13, align 8, !tbaa !9
  store ptr %14, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #3
  %15 = load ptr, ptr %4, align 8, !tbaa !5
  %16 = getelementptr inbounds %struct.QueueNode, ptr %15, i32 0, i32 0
  %17 = load ptr, ptr %16, align 8, !tbaa !11
  store ptr %17, ptr %5, align 8, !tbaa !5
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  %19 = getelementptr inbounds %struct.Queue, ptr %18, i32 0, i32 0
  %20 = load ptr, ptr %19, align 8, !tbaa !9
  %21 = getelementptr inbounds %struct.QueueNode, ptr %20, i32 0, i32 1
  %22 = load ptr, ptr %21, align 8, !tbaa !13
  %23 = load ptr, ptr %3, align 8, !tbaa !5
  %24 = getelementptr inbounds %struct.Queue, ptr %23, i32 0, i32 0
  store ptr %22, ptr %24, align 8, !tbaa !9
  %25 = load ptr, ptr %3, align 8, !tbaa !5
  %26 = getelementptr inbounds %struct.Queue, ptr %25, i32 0, i32 0
  %27 = load ptr, ptr %26, align 8, !tbaa !9
  %28 = icmp eq ptr %27, null
  br i1 %28, label %29, label %32

29:                                               ; preds = %11
  %30 = load ptr, ptr %3, align 8, !tbaa !5
  %31 = getelementptr inbounds %struct.Queue, ptr %30, i32 0, i32 1
  store ptr null, ptr %31, align 8, !tbaa !14
  br label %32

32:                                               ; preds = %29, %11
  %33 = load ptr, ptr %4, align 8, !tbaa !5
  call void @free(ptr noundef %33) #3
  %34 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %34, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  br label %35

35:                                               ; preds = %32, %10
  %36 = load ptr, ptr %2, align 8
  ret ptr %36
}

; Function Attrs: nounwind
declare void @free(ptr noundef) #2

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #2 = { 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, !6, i64 0}
!10 = !{!"Queue", !6, i64 0, !6, i64 8}
!11 = !{!12, !6, i64 0}
!12 = !{!"QueueNode", !6, i64 0, !6, i64 8}
!13 = !{!12, !6, i64 8}
!14 = !{!10, !6, i64 8}


; 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"

; Function Attrs: mustprogress nounwind willreturn uwtable
define dso_local ptr @dequeue(ptr nocapture noundef %0) local_unnamed_addr #0 {
  %2 = load ptr, ptr %0, align 8, !tbaa !5
  %3 = icmp eq ptr %2, null
  br i1 %3, label %12, label %4

4:                                                ; preds = %1
  %5 = load ptr, ptr %2, align 8, !tbaa !10
  %6 = getelementptr inbounds i8, ptr %2, i64 8
  %7 = load ptr, ptr %6, align 8, !tbaa !12
  store ptr %7, ptr %0, align 8, !tbaa !5
  %8 = icmp eq ptr %7, null
  br i1 %8, label %9, label %11

9:                                                ; preds = %4
  %10 = getelementptr inbounds i8, ptr %0, i64 8
  store ptr null, ptr %10, align 8, !tbaa !13
  br label %11

11:                                               ; preds = %9, %4
  tail call void @free(ptr noundef nonnull %2) #2
  br label %12

12:                                               ; preds = %1, %11
  %.0 = phi ptr [ %5, %11 ], [ null, %1 ]
  ret ptr %.0
}

; Function Attrs: mustprogress nounwind willreturn allockind("free") memory(argmem: readwrite, inaccessiblemem: readwrite)
declare void @free(ptr allocptr nocapture noundef) local_unnamed_addr #1

attributes #0 = { mustprogress nounwind willreturn 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 nounwind willreturn allockind("free") memory(argmem: readwrite, inaccessiblemem: readwrite) "alloc-family"="malloc" "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 #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, !7, i64 0}
!6 = !{!"Queue", !7, i64 0, !7, i64 8}
!7 = !{!"any pointer", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = !{!11, !7, i64 0}
!11 = !{!"QueueNode", !7, i64 0, !7, i64 8}
!12 = !{!11, !7, i64 8}
!13 = !{!6, !7, i64 8}


; Effective O3 passes: CorrelatedValuePropagationPass,EarlyCSEPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass