; LLVM IR from smv1999/CompetitiveProgrammingQuestionBank :: Data Structures/Linked Lists/Circular Linked Lists (delete_at_begin)

; 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"

%class.cll_node = type { i32, 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: mustprogress nounwind uwtable
define dso_local void @_Z15delete_at_beginRP8cll_node(ptr noundef nonnull align 8 dereferenceable(8) %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  %4 = load ptr, ptr %2, align 8, !tbaa !5
  %5 = load ptr, ptr %4, align 8, !tbaa !5
  %6 = icmp eq ptr %5, null
  br i1 %6, label %15, label %7

7:                                                ; preds = %1
  %8 = load ptr, ptr %2, align 8, !tbaa !5
  %9 = load ptr, ptr %8, align 8, !tbaa !5
  %10 = getelementptr inbounds %class.cll_node, ptr %9, i32 0, i32 1
  %11 = load ptr, ptr %10, align 8, !tbaa !9
  %12 = load ptr, ptr %2, align 8, !tbaa !5
  %13 = load ptr, ptr %12, align 8, !tbaa !5
  %14 = icmp eq ptr %11, %13
  br i1 %14, label %15, label %22

15:                                               ; preds = %7, %1
  %16 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr null, ptr %16, align 8, !tbaa !5
  %17 = load ptr, ptr %2, align 8, !tbaa !5
  %18 = load ptr, ptr %17, align 8, !tbaa !5
  %19 = icmp eq ptr %18, null
  br i1 %19, label %21, label %20

20:                                               ; preds = %15
  call void @_ZdlPvm(ptr noundef %18, i64 noundef 16) #3
  br label %21

21:                                               ; preds = %20, %15
  br label %54

22:                                               ; preds = %7
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #4
  %23 = load ptr, ptr %2, align 8, !tbaa !5
  %24 = load ptr, ptr %23, align 8, !tbaa !5
  store ptr %24, ptr %3, align 8, !tbaa !5
  br label %25

25:                                               ; preds = %32, %22
  %26 = load ptr, ptr %3, align 8, !tbaa !5
  %27 = getelementptr inbounds %class.cll_node, ptr %26, i32 0, i32 1
  %28 = load ptr, ptr %27, align 8, !tbaa !9
  %29 = load ptr, ptr %2, align 8, !tbaa !5
  %30 = load ptr, ptr %29, align 8, !tbaa !5
  %31 = icmp ne ptr %28, %30
  br i1 %31, label %32, label %36

32:                                               ; preds = %25
  %33 = load ptr, ptr %3, align 8, !tbaa !5
  %34 = getelementptr inbounds %class.cll_node, ptr %33, i32 0, i32 1
  %35 = load ptr, ptr %34, align 8, !tbaa !9
  store ptr %35, ptr %3, align 8, !tbaa !5
  br label %25, !llvm.loop !12

36:                                               ; preds = %25
  %37 = load ptr, ptr %2, align 8, !tbaa !5
  %38 = load ptr, ptr %37, align 8, !tbaa !5
  %39 = getelementptr inbounds %class.cll_node, ptr %38, i32 0, i32 1
  %40 = load ptr, ptr %39, align 8, !tbaa !9
  %41 = load ptr, ptr %3, align 8, !tbaa !5
  %42 = getelementptr inbounds %class.cll_node, ptr %41, i32 0, i32 1
  store ptr %40, ptr %42, align 8, !tbaa !9
  %43 = load ptr, ptr %2, align 8, !tbaa !5
  %44 = load ptr, ptr %43, align 8, !tbaa !5
  store ptr %44, ptr %3, align 8, !tbaa !5
  %45 = load ptr, ptr %2, align 8, !tbaa !5
  %46 = load ptr, ptr %45, align 8, !tbaa !5
  %47 = getelementptr inbounds %class.cll_node, ptr %46, i32 0, i32 1
  %48 = load ptr, ptr %47, align 8, !tbaa !9
  %49 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %48, ptr %49, align 8, !tbaa !5
  %50 = load ptr, ptr %3, align 8, !tbaa !5
  %51 = icmp eq ptr %50, null
  br i1 %51, label %53, label %52

52:                                               ; preds = %36
  call void @_ZdlPvm(ptr noundef %50, i64 noundef 16) #3
  br label %53

53:                                               ; preds = %52, %36
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #4
  br label %54

54:                                               ; preds = %53, %21
  ret void
}

; Function Attrs: nobuiltin nounwind
declare void @_ZdlPvm(ptr noundef, i64 noundef) #2

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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 = { nobuiltin 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 = { builtin nounwind }
attributes #4 = { 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++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS8cll_node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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"

; Function Attrs: mustprogress nounwind uwtable
define dso_local void @_Z15delete_at_beginRP8cll_node(ptr nocapture noundef nonnull align 8 dereferenceable(8) %0) local_unnamed_addr #0 {
  %2 = load ptr, ptr %0, align 8, !tbaa !5
  %3 = icmp eq ptr %2, null
  br i1 %3, label %8, label %4

4:                                                ; preds = %1
  %5 = getelementptr inbounds i8, ptr %2, i64 8
  %6 = load ptr, ptr %5, align 8, !tbaa !9
  %7 = icmp eq ptr %6, %2
  br i1 %7, label %8, label %.preheader

8:                                                ; preds = %4, %1
  store ptr null, ptr %0, align 8, !tbaa !5
  br label %16

.preheader:                                       ; preds = %4, %.preheader
  %.0 = phi ptr [ %10, %.preheader ], [ %2, %4 ]
  %9 = getelementptr inbounds i8, ptr %.0, i64 8
  %10 = load ptr, ptr %9, align 8, !tbaa !9
  %.not = icmp eq ptr %10, %2
  br i1 %.not, label %11, label %.preheader, !llvm.loop !12

11:                                               ; preds = %.preheader
  %12 = getelementptr inbounds i8, ptr %.0, i64 8
  store ptr %6, ptr %12, align 8, !tbaa !9
  %13 = load ptr, ptr %0, align 8, !tbaa !5
  %14 = getelementptr inbounds i8, ptr %13, i64 8
  %15 = load ptr, ptr %14, align 8, !tbaa !9
  store ptr %15, ptr %0, align 8, !tbaa !5
  tail call void @_ZdlPvm(ptr noundef %13, i64 noundef 16) #2
  br label %16

16:                                               ; preds = %11, %8
  ret void
}

; Function Attrs: nobuiltin nounwind
declare void @_ZdlPvm(ptr noundef, i64 noundef) local_unnamed_addr #1

attributes #0 = { mustprogress 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 = { nobuiltin 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 #2 = { builtin 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++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS8cll_node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass