; LLVM IR from lolosssss/leetcode :: c (206_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.ListNode = type { i32, ptr }

; Function Attrs: nounwind uwtable
define dso_local ptr @reverseList(ptr noundef %0) #0 {
  %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
  %7 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  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
  store ptr null, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  store ptr null, ptr %6, align 8, !tbaa !5
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  %9 = icmp eq ptr %8, null
  br i1 %9, label %10, label %12

10:                                               ; preds = %1
  %11 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %11, ptr %2, align 8
  store i32 1, ptr %7, align 4
  br label %41

12:                                               ; preds = %1
  %13 = load ptr, ptr %3, align 8, !tbaa !5
  %14 = getelementptr inbounds %struct.ListNode, ptr %13, i32 0, i32 1
  %15 = load ptr, ptr %14, align 8, !tbaa !9
  %16 = icmp eq ptr %15, null
  br i1 %16, label %17, label %19

17:                                               ; preds = %12
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %18, ptr %2, align 8
  store i32 1, ptr %7, align 4
  br label %41

19:                                               ; preds = %12
  store ptr null, ptr %4, align 8, !tbaa !5
  %20 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %20, ptr %5, align 8, !tbaa !5
  %21 = load ptr, ptr %3, align 8, !tbaa !5
  %22 = getelementptr inbounds %struct.ListNode, ptr %21, i32 0, i32 1
  %23 = load ptr, ptr %22, align 8, !tbaa !9
  store ptr %23, ptr %6, align 8, !tbaa !5
  br label %24

24:                                               ; preds = %27, %19
  %25 = load ptr, ptr %6, align 8, !tbaa !5
  %26 = icmp ne ptr %25, null
  br i1 %26, label %27, label %36

27:                                               ; preds = %24
  %28 = load ptr, ptr %4, align 8, !tbaa !5
  %29 = load ptr, ptr %5, align 8, !tbaa !5
  %30 = getelementptr inbounds %struct.ListNode, ptr %29, i32 0, i32 1
  store ptr %28, ptr %30, align 8, !tbaa !9
  %31 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %31, ptr %4, align 8, !tbaa !5
  %32 = load ptr, ptr %6, align 8, !tbaa !5
  store ptr %32, ptr %5, align 8, !tbaa !5
  %33 = load ptr, ptr %6, align 8, !tbaa !5
  %34 = getelementptr inbounds %struct.ListNode, ptr %33, i32 0, i32 1
  %35 = load ptr, ptr %34, align 8, !tbaa !9
  store ptr %35, ptr %6, align 8, !tbaa !5
  br label %24, !llvm.loop !12

36:                                               ; preds = %24
  %37 = load ptr, ptr %4, align 8, !tbaa !5
  %38 = load ptr, ptr %5, align 8, !tbaa !5
  %39 = getelementptr inbounds %struct.ListNode, ptr %38, i32 0, i32 1
  store ptr %37, ptr %39, align 8, !tbaa !9
  %40 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %40, ptr %2, align 8
  store i32 1, ptr %7, align 4
  br label %41

41:                                               ; preds = %36, %17, %10
  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
  %42 = load ptr, ptr %2, align 8
  ret ptr %42
}

; 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 = { 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 = { 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/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 %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 %.preheader

.preheader:                                       ; preds = %3, %.preheader
  %.023 = phi ptr [ %9, %.preheader ], [ %5, %3 ]
  %.01622 = phi ptr [ %.023, %.preheader ], [ %0, %3 ]
  %.01721 = phi ptr [ %.01622, %.preheader ], [ null, %3 ]
  %7 = getelementptr inbounds i8, ptr %.01622, i64 8
  store ptr %.01721, ptr %7, align 8, !tbaa !5
  %8 = getelementptr inbounds i8, ptr %.023, i64 8
  %9 = load ptr, ptr %8, align 8, !tbaa !5
  %.not = icmp eq ptr %9, null
  br i1 %.not, label %10, label %.preheader, !llvm.loop !11

10:                                               ; preds = %.preheader
  %11 = getelementptr inbounds i8, ptr %.023, i64 8
  store ptr %.01622, ptr %11, align 8, !tbaa !5
  br label %12

12:                                               ; preds = %3, %1, %10
  %.018 = phi ptr [ %.023, %10 ], [ null, %1 ], [ %0, %3 ]
  ret ptr %.018
}

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,LCSSAPass,LICMPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass