; LLVM IR from VAR-solutions/Algorithms :: LinkedList/Reverse-DoublyLinkedList/CPP (ReverseDoublyLinkedList)

; 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.DoublyLinkedListNode = type { i32, ptr, 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 uwtable
define dso_local noundef ptr @_Z7reverseP20DoublyLinkedListNode(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %6 = load ptr, ptr %3, align 8, !tbaa !5
  %7 = getelementptr inbounds %class.DoublyLinkedListNode, ptr %6, i32 0, i32 1
  %8 = load ptr, ptr %7, align 8, !tbaa !9
  store ptr %8, ptr %4, align 8, !tbaa !5
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = getelementptr inbounds %class.DoublyLinkedListNode, ptr %9, i32 0, i32 2
  %11 = load ptr, ptr %10, align 8, !tbaa !12
  %12 = load ptr, ptr %3, align 8, !tbaa !5
  %13 = getelementptr inbounds %class.DoublyLinkedListNode, ptr %12, i32 0, i32 1
  store ptr %11, ptr %13, align 8, !tbaa !9
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  %15 = load ptr, ptr %3, align 8, !tbaa !5
  %16 = getelementptr inbounds %class.DoublyLinkedListNode, ptr %15, i32 0, i32 2
  store ptr %14, ptr %16, align 8, !tbaa !12
  %17 = load ptr, ptr %3, align 8, !tbaa !5
  %18 = getelementptr inbounds %class.DoublyLinkedListNode, ptr %17, i32 0, i32 2
  %19 = load ptr, ptr %18, align 8, !tbaa !12
  %20 = icmp eq ptr %19, null
  br i1 %20, label %21, label %23

21:                                               ; preds = %1
  %22 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %22, ptr %2, align 8
  store i32 1, ptr %5, align 4
  br label %28

23:                                               ; preds = %1
  %24 = load ptr, ptr %3, align 8, !tbaa !5
  %25 = getelementptr inbounds %class.DoublyLinkedListNode, ptr %24, i32 0, i32 2
  %26 = load ptr, ptr %25, align 8, !tbaa !12
  %27 = call noundef ptr @_Z7reverseP20DoublyLinkedListNode(ptr noundef %26)
  store ptr %27, ptr %2, align 8
  store i32 1, ptr %5, align 4
  br label %28

28:                                               ; preds = %23, %21
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  %29 = load ptr, ptr %2, align 8
  ret ptr %29
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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 = { 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 = !{!"_ZTS20DoublyLinkedListNode", !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"

; Function Attrs: mustprogress nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local noundef ptr @_Z7reverseP20DoublyLinkedListNode(ptr noundef %0) local_unnamed_addr #0 {
  br label %tailrecurse

tailrecurse:                                      ; preds = %tailrecurse, %1
  %.tr = phi ptr [ %0, %1 ], [ %3, %tailrecurse ]
  %2 = getelementptr inbounds i8, ptr %.tr, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !5
  %4 = getelementptr inbounds i8, ptr %.tr, i64 16
  %5 = load ptr, ptr %4, align 8, !tbaa !11
  store ptr %5, ptr %2, align 8, !tbaa !5
  store ptr %3, ptr %4, align 8, !tbaa !11
  %6 = icmp eq ptr %3, null
  br i1 %6, label %7, label %tailrecurse

7:                                                ; preds = %tailrecurse
  ret ptr %.tr
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind memory(readwrite, 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, !10, i64 8}
!6 = !{!"_ZTS20DoublyLinkedListNode", !7, i64 0, !10, i64 8, !10, i64 16}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}
!11 = !{!6, !10, i64 16}


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