; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 10. Linked List/MergeSortLinkedList.ll (Z8midPointP4Node)

; 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.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 @_Z8midPointP4Node(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 i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %7, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %8, ptr %5, align 8, !tbaa !5
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = icmp eq ptr %9, null
  br i1 %10, label %16, label %11

11:                                               ; preds = %1
  %12 = load ptr, ptr %3, align 8, !tbaa !5
  %13 = getelementptr inbounds %class.Node, ptr %12, i32 0, i32 1
  %14 = load ptr, ptr %13, align 8, !tbaa !9
  %15 = icmp eq ptr %14, null
  br i1 %15, label %16, label %18

16:                                               ; preds = %11, %1
  %17 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %17, ptr %2, align 8
  store i32 1, ptr %6, align 4
  br label %44

18:                                               ; preds = %11
  br label %19

19:                                               ; preds = %33, %18
  %20 = load ptr, ptr %5, align 8, !tbaa !5
  %21 = getelementptr inbounds %class.Node, ptr %20, i32 0, i32 1
  %22 = load ptr, ptr %21, align 8, !tbaa !9
  %23 = icmp ne ptr %22, null
  br i1 %23, label %24, label %31

24:                                               ; preds = %19
  %25 = load ptr, ptr %5, align 8, !tbaa !5
  %26 = getelementptr inbounds %class.Node, ptr %25, i32 0, i32 1
  %27 = load ptr, ptr %26, align 8, !tbaa !9
  %28 = getelementptr inbounds %class.Node, ptr %27, i32 0, i32 1
  %29 = load ptr, ptr %28, align 8, !tbaa !9
  %30 = icmp ne ptr %29, null
  br label %31

31:                                               ; preds = %24, %19
  %32 = phi i1 [ false, %19 ], [ %30, %24 ]
  br i1 %32, label %33, label %42

33:                                               ; preds = %31
  %34 = load ptr, ptr %4, align 8, !tbaa !5
  %35 = getelementptr inbounds %class.Node, ptr %34, i32 0, i32 1
  %36 = load ptr, ptr %35, align 8, !tbaa !9
  store ptr %36, ptr %4, align 8, !tbaa !5
  %37 = load ptr, ptr %5, align 8, !tbaa !5
  %38 = getelementptr inbounds %class.Node, ptr %37, i32 0, i32 1
  %39 = load ptr, ptr %38, align 8, !tbaa !9
  %40 = getelementptr inbounds %class.Node, ptr %39, i32 0, i32 1
  %41 = load ptr, ptr %40, align 8, !tbaa !9
  store ptr %41, ptr %5, align 8, !tbaa !5
  br label %19, !llvm.loop !12

42:                                               ; preds = %31
  %43 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %43, ptr %2, align 8
  store i32 1, ptr %6, align 4
  br label %44

44:                                               ; preds = %42, %16
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  %45 = load ptr, ptr %2, align 8
  ret ptr %45
}

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 willreturn memory(read, inaccessiblemem: none) uwtable
define dso_local noundef ptr @_Z8midPointP4Node(ptr noundef readonly %0) local_unnamed_addr #0 {
  %2 = icmp eq ptr %0, null
  br i1 %2, label %.critedge, 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 %.critedge, label %.lr.ph

.lr.ph:                                           ; preds = %3, %10
  %7 = phi ptr [ %14, %10 ], [ %5, %3 ]
  %.01118 = phi ptr [ %12, %10 ], [ %0, %3 ]
  %8 = getelementptr inbounds i8, ptr %7, i64 8
  %9 = load ptr, ptr %8, align 8, !tbaa !5
  %.not16 = icmp eq ptr %9, null
  br i1 %.not16, label %.critedge, label %10

10:                                               ; preds = %.lr.ph
  %11 = getelementptr inbounds i8, ptr %.01118, i64 8
  %12 = load ptr, ptr %11, align 8, !tbaa !5
  %13 = getelementptr inbounds i8, ptr %9, i64 8
  %14 = load ptr, ptr %13, align 8, !tbaa !5
  %.not = icmp eq ptr %14, null
  br i1 %.not, label %.critedge, label %.lr.ph, !llvm.loop !11

.critedge:                                        ; preds = %10, %.lr.ph, %1, %3
  %.012 = phi ptr [ %0, %3 ], [ null, %1 ], [ %12, %10 ], [ %.01118, %.lr.ph ]
  ret ptr %.012
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(read, 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: CorrelatedValuePropagationPass,EarlyCSEPass,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SCCPPass,SROAPass,SimplifyCFGPass