; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 10. Linked List/c lang/CircularDoublyLinkedList (Deleting)

; 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 }

@start = external dso_local global ptr, align 8

; Function Attrs: nounwind uwtable
define dso_local i32 @sizeofList() #0 {
  %1 = alloca i32, align 4
  %2 = alloca ptr, align 8
  call void @llvm.lifetime.start.p0(i64 4, ptr %1) #2
  store i32 0, ptr %1, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %2) #2
  %3 = load ptr, ptr @start, align 8, !tbaa !9
  store ptr %3, ptr %2, align 8, !tbaa !9
  br label %4

4:                                                ; preds = %10, %0
  %5 = load ptr, ptr %2, align 8, !tbaa !9
  %6 = getelementptr inbounds %struct.node, ptr %5, i32 0, i32 2
  %7 = load ptr, ptr %6, align 8, !tbaa !11
  %8 = load ptr, ptr @start, align 8, !tbaa !9
  %9 = icmp ne ptr %7, %8
  br i1 %9, label %10, label %16

10:                                               ; preds = %4
  %11 = load i32, ptr %1, align 4, !tbaa !5
  %12 = add nsw i32 %11, 1
  store i32 %12, ptr %1, align 4, !tbaa !5
  %13 = load ptr, ptr %2, align 8, !tbaa !9
  %14 = getelementptr inbounds %struct.node, ptr %13, i32 0, i32 2
  %15 = load ptr, ptr %14, align 8, !tbaa !11
  store ptr %15, ptr %2, align 8, !tbaa !9
  br label %4, !llvm.loop !13

16:                                               ; preds = %4
  %17 = load i32, ptr %1, align 4, !tbaa !5
  %18 = add nsw i32 %17, 1
  store i32 %18, ptr %1, align 4, !tbaa !5
  %19 = load i32, ptr %1, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %2) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %1) #2
  ret i32 %19
}

; 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

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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"any pointer", !7, i64 0}
!11 = !{!12, !10, i64 16}
!12 = !{!"node", !6, i64 0, !10, i64 8, !10, i64 16}
!13 = distinct !{!13, !14}
!14 = !{!"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"

@start = external dso_local local_unnamed_addr global ptr, align 8

; Function Attrs: nofree norecurse nosync nounwind memory(read, inaccessiblemem: none) uwtable
define dso_local range(i32 -2147483647, -2147483648) i32 @sizeofList() local_unnamed_addr #0 {
  %1 = load ptr, ptr @start, align 8, !tbaa !5
  br label %2

2:                                                ; preds = %2, %0
  %.04 = phi i32 [ 0, %0 ], [ %5, %2 ]
  %.0 = phi ptr [ %1, %0 ], [ %4, %2 ]
  %3 = getelementptr inbounds i8, ptr %.0, i64 16
  %4 = load ptr, ptr %3, align 8, !tbaa !9
  %.not = icmp eq ptr %4, %1
  %5 = add nuw nsw i32 %.04, 1
  br i1 %.not, label %6, label %2, !llvm.loop !12

6:                                                ; preds = %2
  ret i32 %5
}

attributes #0 = { nofree norecurse nosync nounwind memory(read, inaccessiblemem: none) 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 16}
!10 = !{!"node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,LCSSAPass,LoopRotatePass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass