; 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
@last = external dso_local global ptr, align 8
@.str.8 = external hidden unnamed_addr constant [3 x i8], align 1
@.str.27 = external hidden unnamed_addr constant [24 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

declare i32 @__isoc99_scanf(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 allocsize(0)
declare noalias ptr @malloc(i64 noundef) #2

; Function Attrs: nounwind uwtable
define dso_local void @inserlast() #3 {
  %1 = alloca ptr, align 8
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 8, ptr %1) #4
  call void @llvm.lifetime.start.p0(i64 8, ptr %2) #4
  %4 = call noalias ptr @malloc(i64 noundef 24) #5
  store ptr %4, ptr %1, align 8, !tbaa !5
  %5 = call i32 (ptr, ...) @printf(ptr noundef @.str.27)
  %6 = load ptr, ptr %1, align 8, !tbaa !5
  %7 = getelementptr inbounds %struct.node, ptr %6, i32 0, i32 0
  %8 = load i32, ptr %7, align 8, !tbaa !9
  %9 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str.8, i32 noundef %8)
  %10 = load ptr, ptr @header, align 8, !tbaa !5
  %11 = icmp eq ptr %10, null
  br i1 %11, label %12, label %18

12:                                               ; preds = %0
  %13 = load ptr, ptr %1, align 8, !tbaa !5
  store ptr %13, ptr %2, align 8, !tbaa !5
  store ptr %13, ptr @header, align 8, !tbaa !5
  %14 = load ptr, ptr %1, align 8, !tbaa !5
  %15 = getelementptr inbounds %struct.node, ptr %14, i32 0, i32 1
  store ptr null, ptr %15, align 8, !tbaa !12
  %16 = load ptr, ptr %1, align 8, !tbaa !5
  %17 = getelementptr inbounds %struct.node, ptr %16, i32 0, i32 2
  store ptr null, ptr %17, align 8, !tbaa !13
  store i32 1, ptr %3, align 4
  br label %39

18:                                               ; preds = %0
  %19 = load ptr, ptr %1, align 8, !tbaa !5
  %20 = load ptr, ptr %2, align 8, !tbaa !5
  %21 = getelementptr inbounds %struct.node, ptr %20, i32 0, i32 1
  store ptr %19, ptr %21, align 8, !tbaa !12
  %22 = load ptr, ptr %1, align 8, !tbaa !5
  %23 = getelementptr inbounds %struct.node, ptr %22, i32 0, i32 1
  store ptr null, ptr %23, align 8, !tbaa !12
  %24 = load ptr, ptr %2, align 8, !tbaa !5
  %25 = load ptr, ptr %1, align 8, !tbaa !5
  %26 = getelementptr inbounds %struct.node, ptr %25, i32 0, i32 2
  store ptr %24, ptr %26, align 8, !tbaa !13
  %27 = load ptr, ptr %1, align 8, !tbaa !5
  store ptr %27, ptr %2, align 8, !tbaa !5
  br label %28

28:                                               ; preds = %18
  %29 = load ptr, ptr %1, align 8, !tbaa !5
  %30 = getelementptr inbounds %struct.node, ptr %29, i32 0, i32 1
  store ptr null, ptr %30, align 8, !tbaa !12
  %31 = load ptr, ptr %1, align 8, !tbaa !5
  %32 = getelementptr inbounds %struct.node, ptr %31, i32 0, i32 2
  store ptr null, ptr %32, align 8, !tbaa !13
  %33 = load ptr, ptr %1, align 8, !tbaa !5
  %34 = load ptr, ptr @last, align 8, !tbaa !5
  %35 = getelementptr inbounds %struct.node, ptr %34, i32 0, i32 1
  store ptr %33, ptr %35, align 8, !tbaa !12
  %36 = load ptr, ptr @last, align 8, !tbaa !5
  %37 = load ptr, ptr %1, align 8, !tbaa !5
  %38 = getelementptr inbounds %struct.node, ptr %37, i32 0, i32 2
  store ptr %36, ptr %38, align 8, !tbaa !13
  store i32 0, ptr %3, align 4
  br label %39

39:                                               ; preds = %28, %12
  call void @llvm.lifetime.end.p0(i64 8, ptr %2) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %1) #4
  %40 = load i32, ptr %3, align 4
  switch i32 %40, label %42 [
    i32 0, label %41
    i32 1, label %41
  ]

41:                                               ; preds = %39, %39
  ret void

42:                                               ; preds = %39
  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 allocsize(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 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 #4 = { nounwind }
attributes #5 = { nounwind allocsize(0) }

!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, !11, i64 0}
!10 = !{!"node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 8}
!13 = !{!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.8 = external hidden unnamed_addr constant [3 x i8], align 1
@.str.27 = external hidden unnamed_addr constant [24 x i8], align 1

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

; Function Attrs: nofree nounwind
declare noundef i32 @__isoc99_scanf(ptr nocapture noundef readonly, ...) local_unnamed_addr #0

; Function Attrs: mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite)
declare noalias noundef ptr @malloc(i64 noundef) local_unnamed_addr #1

; Function Attrs: nofree nounwind uwtable
define dso_local void @inserlast() local_unnamed_addr #2 {
  %1 = tail call noalias dereferenceable_or_null(24) ptr @malloc(i64 noundef 24) #5
  %2 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.27)
  %3 = tail call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str.8, i32 noundef undef)
  %4 = load ptr, ptr @header, align 8, !tbaa !5
  %5 = icmp eq ptr %4, null
  tail call void @llvm.assume(i1 %5)
  store ptr %1, ptr @header, align 8, !tbaa !5
  %6 = getelementptr inbounds i8, ptr %1, i64 8
  tail call void @llvm.memset.p0.i64(ptr noundef nonnull align 8 dereferenceable(16) %6, i8 0, i64 16, i1 false)
  ret void
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write)
declare void @llvm.assume(i1 noundef) #3

; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: write)
declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #4

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 = { mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(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 = { 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" }
attributes #3 = { nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) }
attributes #4 = { nocallback nofree nounwind willreturn memory(argmem: write) }
attributes #5 = { nounwind allocsize(0) }

!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,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,MemCpyOptPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass