; LLVM IR from smv1999/CompetitiveProgrammingQuestionBank :: Data Structures/Linked Lists/Doubly Linked List (recursive_reverse)

; 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.dll_node = type { ptr, i32, 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 @_Z17recursive_reverseP8dll_node(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %6 = load ptr, ptr %3, align 8, !tbaa !5
  %7 = icmp eq ptr %6, null
  br i1 %7, label %13, label %8

8:                                                ; preds = %1
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = getelementptr inbounds %class.dll_node, ptr %9, i32 0, i32 2
  %11 = load ptr, ptr %10, align 8, !tbaa !9
  %12 = icmp eq ptr %11, null
  br i1 %12, label %13, label %15

13:                                               ; preds = %8, %1
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %14, ptr %2, align 8
  br label %32

15:                                               ; preds = %8
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  %17 = getelementptr inbounds %class.dll_node, ptr %16, i32 0, i32 2
  %18 = load ptr, ptr %17, align 8, !tbaa !9
  store ptr %18, ptr %4, align 8, !tbaa !5
  %19 = load ptr, ptr %4, align 8, !tbaa !5
  %20 = getelementptr inbounds %class.dll_node, ptr %19, i32 0, i32 0
  store ptr null, ptr %20, align 8, !tbaa !12
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %21 = load ptr, ptr %4, align 8, !tbaa !5
  %22 = call noundef ptr @_Z17recursive_reverseP8dll_node(ptr noundef %21)
  store ptr %22, ptr %5, align 8, !tbaa !5
  %23 = load ptr, ptr %3, align 8, !tbaa !5
  %24 = load ptr, ptr %4, align 8, !tbaa !5
  %25 = getelementptr inbounds %class.dll_node, ptr %24, i32 0, i32 2
  store ptr %23, ptr %25, align 8, !tbaa !9
  %26 = load ptr, ptr %4, align 8, !tbaa !5
  %27 = load ptr, ptr %3, align 8, !tbaa !5
  %28 = getelementptr inbounds %class.dll_node, ptr %27, i32 0, i32 0
  store ptr %26, ptr %28, align 8, !tbaa !12
  %29 = load ptr, ptr %3, align 8, !tbaa !5
  %30 = getelementptr inbounds %class.dll_node, ptr %29, i32 0, i32 2
  store ptr null, ptr %30, align 8, !tbaa !9
  %31 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %31, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  br label %32

32:                                               ; preds = %15, %13
  %33 = load ptr, ptr %2, align 8
  ret ptr %33
}

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 16}
!10 = !{!"_ZTS8dll_node", !6, i64 0, !11, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 0}


; 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 noundef ptr @_Z17recursive_reverseP8dll_node(ptr noundef %0) local_unnamed_addr #0 {
  %2 = icmp eq ptr %0, null
  br i1 %2, label %common.ret15, label %3

3:                                                ; preds = %1
  %4 = getelementptr inbounds i8, ptr %0, i64 16
  %5 = load ptr, ptr %4, align 8, !tbaa !5
  %6 = icmp eq ptr %5, null
  br i1 %6, label %common.ret15, label %7

common.ret15:                                     ; preds = %1, %3, %7
  %common.ret15.op = phi ptr [ %8, %7 ], [ %0, %3 ], [ null, %1 ]
  ret ptr %common.ret15.op

7:                                                ; preds = %3
  store ptr null, ptr %5, align 8, !tbaa !11
  %8 = tail call noundef ptr @_Z17recursive_reverseP8dll_node(ptr noundef nonnull %5)
  %9 = getelementptr inbounds i8, ptr %5, i64 16
  store ptr %0, ptr %9, align 8, !tbaa !5
  store ptr %5, ptr %0, align 8, !tbaa !11
  store ptr null, ptr %4, align 8, !tbaa !5
  br label %common.ret15
}

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, !7, i64 16}
!6 = !{!"_ZTS8dll_node", !7, i64 0, !10, i64 8, !7, i64 16}
!7 = !{!"any pointer", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C++ TBAA"}
!10 = !{!"int", !8, i64 0}
!11 = !{!6, !7, i64 0}


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