; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 10. Linked List/c lang/DoublyLinkedList (doubly-linked-list)

; 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, ptr }

@header = external dso_local global ptr, align 8
@.str.22 = external hidden unnamed_addr constant [23 x i8], align 1

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

declare i32 @printf(ptr noundef, ...) #1

; 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 void @delete1() #2 {
  %1 = alloca ptr, align 8
  %2 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 8, ptr %1) #3
  %3 = load ptr, ptr @header, align 8, !tbaa !5
  store ptr %3, ptr %1, align 8, !tbaa !5
  %4 = load ptr, ptr @header, align 8, !tbaa !5
  %5 = icmp eq ptr %4, null
  br i1 %5, label %6, label %8

6:                                                ; preds = %0
  %7 = call i32 (ptr, ...) @printf(ptr noundef @.str.22)
  store i32 1, ptr %2, align 4
  br label %20

8:                                                ; preds = %0
  %9 = load ptr, ptr @header, align 8, !tbaa !5
  %10 = getelementptr inbounds %struct.node, ptr %9, i32 0, i32 1
  %11 = load ptr, ptr %10, align 8, !tbaa !9
  %12 = icmp eq ptr %11, null
  br i1 %12, label %13, label %14

13:                                               ; preds = %8
  store ptr null, ptr @header, align 8, !tbaa !5
  br label %14

14:                                               ; preds = %13, %8
  %15 = load ptr, ptr @header, align 8, !tbaa !5
  %16 = getelementptr inbounds %struct.node, ptr %15, i32 0, i32 1
  %17 = load ptr, ptr %16, align 8, !tbaa !9
  store ptr %17, ptr @header, align 8, !tbaa !5
  %18 = load ptr, ptr @header, align 8, !tbaa !5
  %19 = getelementptr inbounds %struct.node, ptr %18, i32 0, i32 2
  store ptr null, ptr %19, align 8, !tbaa !12
  store i32 0, ptr %2, align 4
  br label %20

20:                                               ; preds = %14, %6
  call void @llvm.lifetime.end.p0(i64 8, ptr %1) #3
  %21 = load i32, ptr %2, align 4
  switch i32 %21, label %23 [
    i32 0, label %22
    i32 1, label %22
  ]

22:                                               ; preds = %20, %20
  ret void

23:                                               ; preds = %20
  unreachable
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { "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 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 #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 8}
!10 = !{!"node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 16}


; 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"

@header = external dso_local local_unnamed_addr global ptr, align 8
@.str.22 = external hidden unnamed_addr constant [23 x i8], align 1

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

; Function Attrs: nofree nounwind uwtable
define dso_local void @delete1() local_unnamed_addr #1 {
  %1 = load ptr, ptr @header, align 8, !tbaa !5
  %2 = icmp eq ptr %1, null
  br i1 %2, label %3, label %5

3:                                                ; preds = %0
  %4 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.22)
  br label %13

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

9:                                                ; preds = %5
  store ptr null, ptr @header, align 8, !tbaa !5
  %.pre = load ptr, ptr inttoptr (i64 8 to ptr), align 8, !tbaa !9
  br label %10

10:                                               ; preds = %9, %5
  %11 = phi ptr [ %.pre, %9 ], [ %7, %5 ]
  store ptr %11, ptr @header, align 8, !tbaa !5
  %12 = getelementptr inbounds i8, ptr %11, i64 16
  store ptr null, ptr %12, align 8, !tbaa !12
  br label %13

13:                                               ; preds = %10, %3
  ret void
}

attributes #0 = { 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 #1 = { nofree 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"}
!9 = !{!10, !6, i64 8}
!10 = !{!"node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 16}


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