; LLVM IR from next-step-for-interview-prep/Coding-Ninjas-DSA-course_code_and_notes_cpp :: 1/0000000000000287/LinkedList.ll (Z11reverseLL_2P4Node)

; 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.Pair = type { ptr, ptr }
%class.Node = type { i32, ptr }

; Function Attrs: mustprogress uwtable
define dso_local { ptr, ptr } @_Z11reverseLL_2P4Node(ptr noundef %0) #0 {
  %2 = alloca %class.Pair, align 8
  %3 = alloca ptr, align 8
  %4 = alloca %class.Pair, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %5 = load ptr, ptr %3, align 8, !tbaa !5
  %6 = icmp eq ptr %5, null
  br i1 %6, label %12, label %7

7:                                                ; preds = %1
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  %9 = getelementptr inbounds %class.Node, ptr %8, i32 0, i32 1
  %10 = load ptr, ptr %9, align 8, !tbaa !9
  %11 = icmp eq ptr %10, null
  br i1 %11, label %12, label %17

12:                                               ; preds = %7, %1
  %13 = load ptr, ptr %3, align 8, !tbaa !5
  %14 = getelementptr inbounds %class.Pair, ptr %2, i32 0, i32 0
  store ptr %13, ptr %14, align 8, !tbaa !12
  %15 = load ptr, ptr %3, align 8, !tbaa !5
  %16 = getelementptr inbounds %class.Pair, ptr %2, i32 0, i32 1
  store ptr %15, ptr %16, align 8, !tbaa !14
  br label %37

17:                                               ; preds = %7
  call void @llvm.lifetime.start.p0(i64 16, ptr %4) #2
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  %19 = getelementptr inbounds %class.Node, ptr %18, i32 0, i32 1
  %20 = load ptr, ptr %19, align 8, !tbaa !9
  %21 = call { ptr, ptr } @_Z11reverseLL_2P4Node(ptr noundef %20)
  %22 = getelementptr inbounds { ptr, ptr }, ptr %4, i32 0, i32 0
  %23 = extractvalue { ptr, ptr } %21, 0
  store ptr %23, ptr %22, align 8
  %24 = getelementptr inbounds { ptr, ptr }, ptr %4, i32 0, i32 1
  %25 = extractvalue { ptr, ptr } %21, 1
  store ptr %25, ptr %24, align 8
  %26 = load ptr, ptr %3, align 8, !tbaa !5
  %27 = getelementptr inbounds %class.Pair, ptr %4, i32 0, i32 1
  %28 = load ptr, ptr %27, align 8, !tbaa !14
  %29 = getelementptr inbounds %class.Node, ptr %28, i32 0, i32 1
  store ptr %26, ptr %29, align 8, !tbaa !9
  %30 = load ptr, ptr %3, align 8, !tbaa !5
  %31 = getelementptr inbounds %class.Node, ptr %30, i32 0, i32 1
  store ptr null, ptr %31, align 8, !tbaa !9
  %32 = getelementptr inbounds %class.Pair, ptr %4, i32 0, i32 0
  %33 = load ptr, ptr %32, align 8, !tbaa !12
  %34 = getelementptr inbounds %class.Pair, ptr %2, i32 0, i32 0
  store ptr %33, ptr %34, align 8, !tbaa !12
  %35 = load ptr, ptr %3, align 8, !tbaa !5
  %36 = getelementptr inbounds %class.Pair, ptr %2, i32 0, i32 1
  store ptr %35, ptr %36, align 8, !tbaa !14
  call void @llvm.lifetime.end.p0(i64 16, ptr %4) #2
  br label %37

37:                                               ; preds = %17, %12
  %38 = load { ptr, ptr }, ptr %2, align 8
  ret { ptr, ptr } %38
}

; 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 = { 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 #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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS4Node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = !{!13, !6, i64 0}
!13 = !{!"_ZTS4Pair", !6, i64 0, !6, i64 8}
!14 = !{!13, !6, i64 8}


; 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 nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local { ptr, ptr } @_Z11reverseLL_2P4Node(ptr noundef %0) local_unnamed_addr #0 {
  %2 = icmp eq ptr %0, null
  br i1 %2, label %12, label %3

3:                                                ; preds = %1
  %4 = getelementptr inbounds i8, ptr %0, i64 8
  %5 = load ptr, ptr %4, align 8, !tbaa !5
  %6 = icmp eq ptr %5, null
  br i1 %6, label %12, label %7

7:                                                ; preds = %3
  %8 = tail call { ptr, ptr } @_Z11reverseLL_2P4Node(ptr noundef nonnull %5)
  %9 = extractvalue { ptr, ptr } %8, 0
  %10 = extractvalue { ptr, ptr } %8, 1
  %11 = getelementptr inbounds i8, ptr %10, i64 8
  store ptr %0, ptr %11, align 8, !tbaa !5
  store ptr null, ptr %4, align 8, !tbaa !5
  br label %12

12:                                               ; preds = %1, %3, %7
  %.sroa.08.0 = phi ptr [ %9, %7 ], [ %0, %3 ], [ null, %1 ]
  %.fca.0.insert = insertvalue { ptr, ptr } poison, ptr %.sroa.08.0, 0
  %.fca.1.insert = insertvalue { ptr, ptr } %.fca.0.insert, ptr %0, 1
  ret { ptr, ptr } %.fca.1.insert
}

attributes #0 = { mustprogress nofree 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 = !{!"_ZTS4Node", !7, i64 0, !10, i64 8}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}


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