; LLVM IR from HarshCasper/NeoAlgo :: C/ds (reverse_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 }

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind uwtable
define dso_local void @append(ptr noundef %0, i32 noundef %1) #1 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #3
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #3
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  %8 = load ptr, ptr %7, align 8, !tbaa !5
  %9 = icmp eq ptr %8, null
  br i1 %9, label %10, label %19

10:                                               ; preds = %2
  %11 = call noalias ptr @malloc(i64 noundef 16) #4
  store ptr %11, ptr %5, align 8, !tbaa !5
  %12 = load i32, ptr %4, align 4, !tbaa !9
  %13 = load ptr, ptr %5, align 8, !tbaa !5
  %14 = getelementptr inbounds %struct.node, ptr %13, i32 0, i32 0
  store i32 %12, ptr %14, align 8, !tbaa !11
  %15 = load ptr, ptr %5, align 8, !tbaa !5
  %16 = getelementptr inbounds %struct.node, ptr %15, i32 0, i32 1
  store ptr null, ptr %16, align 8, !tbaa !13
  %17 = load ptr, ptr %5, align 8, !tbaa !5
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %17, ptr %18, align 8, !tbaa !5
  br label %41

19:                                               ; preds = %2
  %20 = load ptr, ptr %3, align 8, !tbaa !5
  %21 = load ptr, ptr %20, align 8, !tbaa !5
  store ptr %21, ptr %5, align 8, !tbaa !5
  br label %22

22:                                               ; preds = %27, %19
  %23 = load ptr, ptr %5, align 8, !tbaa !5
  %24 = getelementptr inbounds %struct.node, ptr %23, i32 0, i32 1
  %25 = load ptr, ptr %24, align 8, !tbaa !13
  %26 = icmp ne ptr %25, null
  br i1 %26, label %27, label %31

27:                                               ; preds = %22
  %28 = load ptr, ptr %5, align 8, !tbaa !5
  %29 = getelementptr inbounds %struct.node, ptr %28, i32 0, i32 1
  %30 = load ptr, ptr %29, align 8, !tbaa !13
  store ptr %30, ptr %5, align 8, !tbaa !5
  br label %22, !llvm.loop !14

31:                                               ; preds = %22
  %32 = call noalias ptr @malloc(i64 noundef 16) #4
  store ptr %32, ptr %6, align 8, !tbaa !5
  %33 = load i32, ptr %4, align 4, !tbaa !9
  %34 = load ptr, ptr %6, align 8, !tbaa !5
  %35 = getelementptr inbounds %struct.node, ptr %34, i32 0, i32 0
  store i32 %33, ptr %35, align 8, !tbaa !11
  %36 = load ptr, ptr %6, align 8, !tbaa !5
  %37 = getelementptr inbounds %struct.node, ptr %36, i32 0, i32 1
  store ptr null, ptr %37, align 8, !tbaa !13
  %38 = load ptr, ptr %6, align 8, !tbaa !5
  %39 = load ptr, ptr %5, align 8, !tbaa !5
  %40 = getelementptr inbounds %struct.node, ptr %39, i32 0, i32 1
  store ptr %38, ptr %40, align 8, !tbaa !13
  br label %41

41:                                               ; preds = %31, %10
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #3
  ret void
}

; 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

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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 }
attributes #4 = { 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, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!12, !10, i64 0}
!12 = !{!"node", !10, i64 0, !6, i64 8}
!13 = !{!12, !6, i64 8}
!14 = distinct !{!14, !15}
!15 = !{!"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"

; Function Attrs: nofree nounwind uwtable
define dso_local void @append(ptr nocapture noundef %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = load ptr, ptr %0, align 8, !tbaa !5
  %4 = icmp eq ptr %3, null
  br i1 %4, label %9, label %.preheader

.preheader:                                       ; preds = %2, %.preheader
  %.0 = phi ptr [ %6, %.preheader ], [ %3, %2 ]
  %5 = getelementptr inbounds i8, ptr %.0, i64 8
  %6 = load ptr, ptr %5, align 8, !tbaa !9
  %.not = icmp eq ptr %6, null
  br i1 %.not, label %7, label %.preheader, !llvm.loop !12

7:                                                ; preds = %.preheader
  %8 = getelementptr inbounds i8, ptr %.0, i64 8
  br label %9

9:                                                ; preds = %2, %7
  %.sink15 = phi ptr [ %8, %7 ], [ %0, %2 ]
  %10 = tail call noalias dereferenceable_or_null(16) ptr @malloc(i64 noundef 16) #2
  store i32 %1, ptr %10, align 8, !tbaa !14
  %11 = getelementptr inbounds i8, ptr %10, i64 8
  store ptr null, ptr %11, align 8, !tbaa !9
  store ptr %10, ptr %.sink15, align 8, !tbaa !5
  ret void
}

; 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

attributes #0 = { 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 #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 = { 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, !6, i64 8}
!10 = !{!"node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}
!14 = !{!10, !11, i64 0}


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