; LLVM IR from JessonYue/LeetCodeLearning :: Array/yangxin (linklist)

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

; Function Attrs: nounwind uwtable
define dso_local ptr @reverseList(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  %8 = icmp eq ptr %7, null
  br i1 %8, label %9, label %11

9:                                                ; preds = %1
  %10 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %10, ptr %2, align 8
  br label %33

11:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  store ptr null, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %12 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %12, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  %13 = load ptr, ptr %5, align 8, !tbaa !5
  %14 = getelementptr inbounds %struct.ListNode, ptr %13, i32 0, i32 1
  %15 = load ptr, ptr %14, align 8, !tbaa !9
  store ptr %15, ptr %6, align 8, !tbaa !5
  br label %16

16:                                               ; preds = %19, %11
  %17 = load ptr, ptr %6, align 8, !tbaa !5
  %18 = icmp ne ptr %17, null
  br i1 %18, label %19, label %28

19:                                               ; preds = %16
  %20 = load ptr, ptr %4, align 8, !tbaa !5
  %21 = load ptr, ptr %5, align 8, !tbaa !5
  %22 = getelementptr inbounds %struct.ListNode, ptr %21, i32 0, i32 1
  store ptr %20, ptr %22, align 8, !tbaa !9
  %23 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %23, ptr %4, align 8, !tbaa !5
  %24 = load ptr, ptr %6, align 8, !tbaa !5
  store ptr %24, ptr %5, align 8, !tbaa !5
  %25 = load ptr, ptr %5, align 8, !tbaa !5
  %26 = getelementptr inbounds %struct.ListNode, ptr %25, i32 0, i32 1
  %27 = load ptr, ptr %26, align 8, !tbaa !9
  store ptr %27, ptr %6, align 8, !tbaa !5
  br label %16, !llvm.loop !12

28:                                               ; preds = %16
  %29 = load ptr, ptr %4, align 8, !tbaa !5
  %30 = load ptr, ptr %5, align 8, !tbaa !5
  %31 = getelementptr inbounds %struct.ListNode, ptr %30, i32 0, i32 1
  store ptr %29, ptr %31, align 8, !tbaa !9
  %32 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %32, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  br label %33

33:                                               ; preds = %28, %9
  %34 = load ptr, ptr %2, align 8
  ret ptr %34
}

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 }

!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 = !{!"ListNode", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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 norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local ptr @reverseList(ptr noundef %0) local_unnamed_addr #0 {
  %2 = icmp eq ptr %0, null
  br i1 %2, label %3, label %.preheader

.preheader:                                       ; preds = %1
  %.0.in18 = getelementptr inbounds i8, ptr %0, i64 8
  %.019 = load ptr, ptr %.0.in18, align 8, !tbaa !5
  %.not20 = icmp eq ptr %.019, null
  br i1 %.not20, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %.preheader, %.lr.ph
  %.024 = phi ptr [ %.0, %.lr.ph ], [ %.019, %.preheader ]
  %.0.in23 = phi ptr [ %.0.in, %.lr.ph ], [ %.0.in18, %.preheader ]
  %.01422 = phi ptr [ %.024, %.lr.ph ], [ %0, %.preheader ]
  %.01521 = phi ptr [ %.01422, %.lr.ph ], [ null, %.preheader ]
  store ptr %.01521, ptr %.0.in23, align 8, !tbaa !5
  %.0.in = getelementptr inbounds i8, ptr %.024, i64 8
  %.0 = load ptr, ptr %.0.in, align 8, !tbaa !5
  %.not = icmp eq ptr %.0, null
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !11

._crit_edge:                                      ; preds = %.lr.ph, %.preheader
  %.015.lcssa = phi ptr [ null, %.preheader ], [ %.01422, %.lr.ph ]
  %.014.lcssa = phi ptr [ %0, %.preheader ], [ %.024, %.lr.ph ]
  %.0.in.lcssa = phi ptr [ %.0.in18, %.preheader ], [ %.0.in, %.lr.ph ]
  store ptr %.015.lcssa, ptr %.0.in.lcssa, align 8, !tbaa !5
  br label %3

3:                                                ; preds = %1, %._crit_edge
  %.016 = phi ptr [ %.014.lcssa, %._crit_edge ], [ null, %1 ]
  ret ptr %.016
}

attributes #0 = { 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 = !{!"ListNode", !7, i64 0, !10, i64 8}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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