; LLVM IR from gargarchit/Data_Structure_n_Algorithms :: Linked_List (12_Stack_n_Queue)

; 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.node = type { i32, ptr }

@front = external dso_local global ptr, align 8
@rare = external dso_local global ptr, align 8

; Function Attrs: nounwind uwtable
declare dso_local ptr @getnode() #0

; 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

; Function Attrs: nounwind uwtable
define dso_local void @Enqueue() #0 {
  %1 = alloca ptr, align 8
  %2 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 8, ptr %1) #2
  %3 = call ptr @getnode()
  store ptr %3, ptr %1, align 8, !tbaa !5
  %4 = load ptr, ptr @rare, align 8, !tbaa !5
  %5 = icmp eq ptr %4, null
  br i1 %5, label %6, label %8

6:                                                ; preds = %0
  %7 = load ptr, ptr %1, align 8, !tbaa !5
  store ptr %7, ptr @rare, align 8, !tbaa !5
  store ptr %7, ptr @front, align 8, !tbaa !5
  store i32 1, ptr %2, align 4
  br label %13

8:                                                ; preds = %0
  %9 = load ptr, ptr %1, align 8, !tbaa !5
  %10 = load ptr, ptr @rare, align 8, !tbaa !5
  %11 = getelementptr inbounds %struct.node, ptr %10, i32 0, i32 1
  store ptr %9, ptr %11, align 8, !tbaa !9
  %12 = load ptr, ptr %1, align 8, !tbaa !5
  store ptr %12, ptr @rare, align 8, !tbaa !5
  store i32 1, ptr %2, align 4
  br label %13

13:                                               ; preds = %8, %6
  call void @llvm.lifetime.end.p0(i64 8, ptr %1) #2
  ret void
}

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 = { 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 8}
!10 = !{!"node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !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"

@front = external dso_local local_unnamed_addr global ptr, align 8
@rare = external dso_local local_unnamed_addr global ptr, align 8

; Function Attrs: nounwind uwtable
declare dso_local ptr @getnode() local_unnamed_addr #0

; Function Attrs: nounwind uwtable
define dso_local void @Enqueue() local_unnamed_addr #0 {
  %1 = tail call ptr @getnode()
  %2 = load ptr, ptr @rare, align 8, !tbaa !5
  %3 = icmp eq ptr %2, null
  %4 = getelementptr inbounds i8, ptr %2, i64 8
  %.sink = select i1 %3, ptr @front, ptr %4
  store ptr %1, ptr %.sink, align 8, !tbaa !5
  store ptr %1, ptr @rare, align 8
  ret void
}

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" }

!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"}


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