; LLVM IR from div-bargali/Data-Structures-and-Algorithms :: C++/Data-Structures/LinkedList/MergeSort in Linked List.ll (Z5splitP4node)

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

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef ptr @_Z5splitP4node(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
  %7 = alloca i32, align 4
  %8 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %9, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %10 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %10, ptr %5, align 8, !tbaa !5
  br label %11

11:                                               ; preds = %25, %1
  %12 = load ptr, ptr %4, align 8, !tbaa !5
  %13 = getelementptr inbounds %struct.node, ptr %12, i32 0, i32 1
  %14 = load ptr, ptr %13, align 8, !tbaa !9
  %15 = icmp ne ptr %14, null
  br i1 %15, label %16, label %23

16:                                               ; preds = %11
  %17 = load ptr, ptr %4, align 8, !tbaa !5
  %18 = getelementptr inbounds %struct.node, ptr %17, i32 0, i32 1
  %19 = load ptr, ptr %18, align 8, !tbaa !9
  %20 = getelementptr inbounds %struct.node, ptr %19, i32 0, i32 1
  %21 = load ptr, ptr %20, align 8, !tbaa !9
  %22 = icmp ne ptr %21, null
  br label %23

23:                                               ; preds = %16, %11
  %24 = phi i1 [ false, %11 ], [ %22, %16 ]
  br i1 %24, label %25, label %34

25:                                               ; preds = %23
  %26 = load ptr, ptr %4, align 8, !tbaa !5
  %27 = getelementptr inbounds %struct.node, ptr %26, i32 0, i32 1
  %28 = load ptr, ptr %27, align 8, !tbaa !9
  %29 = getelementptr inbounds %struct.node, ptr %28, i32 0, i32 1
  %30 = load ptr, ptr %29, align 8, !tbaa !9
  store ptr %30, ptr %4, align 8, !tbaa !5
  %31 = load ptr, ptr %5, align 8, !tbaa !5
  %32 = getelementptr inbounds %struct.node, ptr %31, i32 0, i32 1
  %33 = load ptr, ptr %32, align 8, !tbaa !9
  store ptr %33, ptr %5, align 8, !tbaa !5
  br label %11, !llvm.loop !12

34:                                               ; preds = %23
  %35 = load ptr, ptr %4, align 8, !tbaa !5
  %36 = getelementptr inbounds %struct.node, ptr %35, i32 0, i32 1
  %37 = load ptr, ptr %36, align 8, !tbaa !9
  %38 = icmp eq ptr %37, null
  br i1 %38, label %39, label %46

39:                                               ; preds = %34
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  %40 = load ptr, ptr %5, align 8, !tbaa !5
  %41 = getelementptr inbounds %struct.node, ptr %40, i32 0, i32 1
  %42 = load ptr, ptr %41, align 8, !tbaa !9
  store ptr %42, ptr %6, align 8, !tbaa !5
  %43 = load ptr, ptr %5, align 8, !tbaa !5
  %44 = getelementptr inbounds %struct.node, ptr %43, i32 0, i32 1
  store ptr null, ptr %44, align 8, !tbaa !9
  %45 = load ptr, ptr %6, align 8, !tbaa !5
  store ptr %45, ptr %2, align 8
  store i32 1, ptr %7, align 4
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  br label %53

46:                                               ; preds = %34
  call void @llvm.lifetime.start.p0(i64 8, ptr %8) #2
  %47 = load ptr, ptr %5, align 8, !tbaa !5
  %48 = getelementptr inbounds %struct.node, ptr %47, i32 0, i32 1
  %49 = load ptr, ptr %48, align 8, !tbaa !9
  store ptr %49, ptr %8, align 8, !tbaa !5
  %50 = load ptr, ptr %5, align 8, !tbaa !5
  %51 = getelementptr inbounds %struct.node, ptr %50, i32 0, i32 1
  store ptr null, ptr %51, align 8, !tbaa !9
  %52 = load ptr, ptr %8, align 8, !tbaa !5
  store ptr %52, ptr %2, align 8
  store i32 1, ptr %7, align 4
  call void @llvm.lifetime.end.p0(i64 8, ptr %8) #2
  br label %53

53:                                               ; preds = %46, %39
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  %54 = load ptr, ptr %2, align 8
  ret ptr %54
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS4node", !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: mustprogress nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local noundef ptr @_Z5splitP4node(ptr nocapture noundef %0) local_unnamed_addr #0 {
  %2 = getelementptr inbounds i8, ptr %0, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !5
  %.not20 = icmp eq ptr %3, null
  br i1 %.not20, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %1, %9
  %4 = phi ptr [ %11, %9 ], [ %3, %1 ]
  %.01521 = phi ptr [ %8, %9 ], [ %0, %1 ]
  %5 = getelementptr inbounds i8, ptr %4, i64 8
  %6 = load ptr, ptr %5, align 8, !tbaa !5
  %.not18 = icmp eq ptr %6, null
  %7 = getelementptr inbounds i8, ptr %.01521, i64 8
  %8 = load ptr, ptr %7, align 8, !tbaa !5
  br i1 %.not18, label %.critedge.loopexit, label %9

9:                                                ; preds = %.lr.ph
  %10 = getelementptr inbounds i8, ptr %6, i64 8
  %11 = load ptr, ptr %10, align 8, !tbaa !5
  %.not = icmp eq ptr %11, null
  br i1 %.not, label %._crit_edge.loopexit, label %.lr.ph, !llvm.loop !11

._crit_edge.loopexit:                             ; preds = %9
  %.phi.trans.insert = getelementptr inbounds i8, ptr %8, i64 8
  %.pre = load ptr, ptr %.phi.trans.insert, align 8, !tbaa !5
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %1
  %12 = phi ptr [ null, %1 ], [ %.pre, %._crit_edge.loopexit ]
  %.015.lcssa = phi ptr [ %0, %1 ], [ %8, %._crit_edge.loopexit ]
  %13 = getelementptr inbounds i8, ptr %.015.lcssa, i64 8
  br label %.critedge

.critedge.loopexit:                               ; preds = %.lr.ph
  %14 = getelementptr inbounds i8, ptr %.01521, i64 8
  br label %.critedge

.critedge:                                        ; preds = %.critedge.loopexit, %._crit_edge
  %.sink = phi ptr [ %13, %._crit_edge ], [ %14, %.critedge.loopexit ]
  %.0 = phi ptr [ %12, %._crit_edge ], [ %8, %.critedge.loopexit ]
  store ptr null, ptr %.sink, align 8, !tbaa !5
  ret ptr %.0
}

attributes #0 = { mustprogress 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 = !{!"_ZTS4node", !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 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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