; LLVM IR from afrozchakure/Competitive-Programming-Solutions :: HackerRank/Problem-Solving (MergeTwoSortedLinkedLists)

; 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.SinglyLinkedListNode = 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: mustprogress uwtable
define dso_local noundef ptr @_Z10mergeListsP20SinglyLinkedListNodeS0_(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 ptr, align 8
  %9 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  call void @llvm.lifetime.start.p0(i64 8, ptr %7) #2
  call void @llvm.lifetime.start.p0(i64 8, ptr %8) #2
  %10 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %10, ptr %6, align 8, !tbaa !5
  %11 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %11, ptr %7, align 8, !tbaa !5
  %12 = load ptr, ptr %6, align 8, !tbaa !5
  %13 = icmp eq ptr %12, null
  br i1 %13, label %14, label %16

14:                                               ; preds = %2
  %15 = load ptr, ptr %7, align 8, !tbaa !5
  store ptr %15, ptr %3, align 8
  store i32 1, ptr %9, align 4
  br label %50

16:                                               ; preds = %2
  %17 = load ptr, ptr %7, align 8, !tbaa !5
  %18 = icmp eq ptr %17, null
  br i1 %18, label %19, label %21

19:                                               ; preds = %16
  %20 = load ptr, ptr %6, align 8, !tbaa !5
  store ptr %20, ptr %3, align 8
  store i32 1, ptr %9, align 4
  br label %50

21:                                               ; preds = %16
  br label %22

22:                                               ; preds = %21
  %23 = load ptr, ptr %6, align 8, !tbaa !5
  %24 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %23, i32 0, i32 0
  %25 = load i32, ptr %24, align 8, !tbaa !9
  %26 = load ptr, ptr %7, align 8, !tbaa !5
  %27 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %26, i32 0, i32 0
  %28 = load i32, ptr %27, align 8, !tbaa !9
  %29 = icmp sle i32 %25, %28
  br i1 %29, label %30, label %39

30:                                               ; preds = %22
  %31 = load ptr, ptr %6, align 8, !tbaa !5
  store ptr %31, ptr %8, align 8, !tbaa !5
  %32 = load ptr, ptr %6, align 8, !tbaa !5
  %33 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %32, i32 0, i32 1
  %34 = load ptr, ptr %33, align 8, !tbaa !12
  %35 = load ptr, ptr %7, align 8, !tbaa !5
  %36 = call noundef ptr @_Z10mergeListsP20SinglyLinkedListNodeS0_(ptr noundef %34, ptr noundef %35)
  %37 = load ptr, ptr %8, align 8, !tbaa !5
  %38 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %37, i32 0, i32 1
  store ptr %36, ptr %38, align 8, !tbaa !12
  br label %48

39:                                               ; preds = %22
  %40 = load ptr, ptr %7, align 8, !tbaa !5
  store ptr %40, ptr %8, align 8, !tbaa !5
  %41 = load ptr, ptr %6, align 8, !tbaa !5
  %42 = load ptr, ptr %7, align 8, !tbaa !5
  %43 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %42, i32 0, i32 1
  %44 = load ptr, ptr %43, align 8, !tbaa !12
  %45 = call noundef ptr @_Z10mergeListsP20SinglyLinkedListNodeS0_(ptr noundef %41, ptr noundef %44)
  %46 = load ptr, ptr %8, align 8, !tbaa !5
  %47 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %46, i32 0, i32 1
  store ptr %45, ptr %47, align 8, !tbaa !12
  br label %48

48:                                               ; preds = %39, %30
  %49 = load ptr, ptr %8, align 8, !tbaa !5
  store ptr %49, ptr %3, align 8
  store i32 1, ptr %9, align 4
  br label %50

50:                                               ; preds = %48, %19, %14
  call void @llvm.lifetime.end.p0(i64 8, ptr %8) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %7) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  %51 = load ptr, ptr %3, align 8
  ret ptr %51
}

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, !11, i64 0}
!10 = !{!"_ZTS20SinglyLinkedListNode", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 8}


; 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 @_Z10mergeListsP20SinglyLinkedListNodeS0_(ptr noundef %0, ptr noundef %1) local_unnamed_addr #0 {
  %3 = icmp eq ptr %0, null
  br i1 %3, label %common.ret21, label %4

4:                                                ; preds = %2
  %5 = icmp eq ptr %1, null
  br i1 %5, label %common.ret21, label %6

6:                                                ; preds = %4
  %7 = load i32, ptr %0, align 8, !tbaa !5
  %8 = load i32, ptr %1, align 8, !tbaa !5
  %.not = icmp sgt i32 %7, %8
  br i1 %.not, label %13, label %9

common.ret21:                                     ; preds = %4, %2, %13, %9
  %common.ret21.op = phi ptr [ %0, %9 ], [ %1, %13 ], [ %1, %2 ], [ %0, %4 ]
  ret ptr %common.ret21.op

9:                                                ; preds = %6
  %10 = getelementptr inbounds i8, ptr %0, i64 8
  %11 = load ptr, ptr %10, align 8, !tbaa !11
  %12 = tail call noundef ptr @_Z10mergeListsP20SinglyLinkedListNodeS0_(ptr noundef %11, ptr noundef nonnull %1)
  store ptr %12, ptr %10, align 8, !tbaa !11
  br label %common.ret21

13:                                               ; preds = %6
  %14 = getelementptr inbounds i8, ptr %1, i64 8
  %15 = load ptr, ptr %14, align 8, !tbaa !11
  %16 = tail call noundef ptr @_Z10mergeListsP20SinglyLinkedListNodeS0_(ptr noundef nonnull %0, ptr noundef %15)
  store ptr %16, ptr %14, align 8, !tbaa !11
  br label %common.ret21
}

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 0}
!6 = !{!"_ZTS20SinglyLinkedListNode", !7, i64 0, !10, i64 8}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}
!11 = !{!6, !10, i64 8}


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