; LLVM IR from kaynewbie/algorithm :: algorithm/CodingInterviews (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: 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
declare dso_local ptr @findLast(ptr noundef) #1

; Function Attrs: nounwind uwtable
define dso_local ptr @findPreviousNodeOfTarget(ptr noundef %0, ptr noundef %1) #1 {
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  %7 = alloca ptr, align 8
  %8 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !5
  %9 = load ptr, ptr %4, align 8, !tbaa !5
  %10 = icmp eq ptr %9, null
  br i1 %10, label %11, label %12

11:                                               ; preds = %2
  store ptr null, ptr %3, align 8
  br label %39

12:                                               ; preds = %2
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  call void @llvm.lifetime.start.p0(i64 8, ptr %7) #2
  store ptr null, ptr %6, align 8, !tbaa !5
  %13 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %13, ptr %7, align 8, !tbaa !5
  %14 = load ptr, ptr %5, align 8, !tbaa !5
  %15 = icmp eq ptr %14, null
  br i1 %15, label %16, label %19

16:                                               ; preds = %12
  %17 = load ptr, ptr %4, align 8, !tbaa !5
  %18 = call ptr @findLast(ptr noundef %17)
  store ptr %18, ptr %3, align 8
  store i32 1, ptr %8, align 4
  br label %38

19:                                               ; preds = %12
  br label %20

20:                                               ; preds = %31, %19
  %21 = load ptr, ptr %7, align 8, !tbaa !5
  %22 = getelementptr inbounds %struct.ListNode, ptr %21, i32 0, i32 1
  %23 = load ptr, ptr %22, align 8, !tbaa !9
  %24 = icmp ne ptr %23, null
  br i1 %24, label %25, label %29

25:                                               ; preds = %20
  %26 = load ptr, ptr %7, align 8, !tbaa !5
  %27 = load ptr, ptr %5, align 8, !tbaa !5
  %28 = icmp ne ptr %26, %27
  br label %29

29:                                               ; preds = %25, %20
  %30 = phi i1 [ false, %20 ], [ %28, %25 ]
  br i1 %30, label %31, label %36

31:                                               ; preds = %29
  %32 = load ptr, ptr %7, align 8, !tbaa !5
  store ptr %32, ptr %6, align 8, !tbaa !5
  %33 = load ptr, ptr %7, 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 %7, align 8, !tbaa !5
  br label %20, !llvm.loop !12

36:                                               ; preds = %29
  %37 = load ptr, ptr %6, align 8, !tbaa !5
  store ptr %37, ptr %3, align 8
  store i32 1, ptr %8, align 4
  br label %38

38:                                               ; preds = %36, %16
  call void @llvm.lifetime.end.p0(i64 8, ptr %7) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  br label %39

39:                                               ; preds = %38, %11
  %40 = load ptr, ptr %3, align 8
  ret ptr %40
}

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: nounwind uwtable
declare dso_local ptr @findLast(ptr noundef) local_unnamed_addr #0

; Function Attrs: nounwind uwtable
define dso_local ptr @findPreviousNodeOfTarget(ptr noundef %0, ptr noundef readnone %1) local_unnamed_addr #0 {
  %3 = icmp eq ptr %0, null
  br i1 %3, label %.loopexit, label %4

4:                                                ; preds = %2
  %5 = icmp eq ptr %1, null
  br i1 %5, label %6, label %.preheader

6:                                                ; preds = %4
  %7 = tail call ptr @findLast(ptr noundef nonnull %0)
  br label %.loopexit

.preheader:                                       ; preds = %4, %.preheader
  %.011 = phi ptr [ %.0, %.preheader ], [ null, %4 ]
  %.0 = phi ptr [ %9, %.preheader ], [ %0, %4 ]
  %8 = getelementptr inbounds i8, ptr %.0, i64 8
  %9 = load ptr, ptr %8, align 8, !tbaa !5
  %10 = icmp ne ptr %9, null
  %11 = icmp ne ptr %.0, %1
  %12 = and i1 %11, %10
  br i1 %12, label %.preheader, label %.loopexit, !llvm.loop !11

.loopexit:                                        ; preds = %.preheader, %6, %2
  %.1 = phi ptr [ null, %2 ], [ %7, %6 ], [ %.011, %.preheader ]
  ret ptr %.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" }

!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,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass