; LLVM IR from HarshCasper/NeoAlgo :: C-Plus-Plus/ds/MergeSortLL.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
  store ptr %0, ptr %3, align 8, !tbaa !5
  %6 = load ptr, ptr %3, align 8, !tbaa !5
  %7 = icmp eq ptr %6, null
  br i1 %7, label %13, label %8

8:                                                ; preds = %1
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = getelementptr inbounds %class.Node, ptr %9, i32 0, i32 1
  %11 = load ptr, ptr %10, align 8, !tbaa !9
  %12 = icmp eq ptr %11, null
  br i1 %12, label %13, label %15

13:                                               ; preds = %8, %1
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %14, ptr %2, align 8
  br label %41

15:                                               ; preds = %8
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %16, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %17 = load ptr, ptr %3, align 8, !tbaa !5
  %18 = getelementptr inbounds %class.Node, ptr %17, i32 0, i32 1
  %19 = load ptr, ptr %18, align 8, !tbaa !9
  store ptr %19, ptr %5, align 8, !tbaa !5
  br label %20

20:                                               ; preds = %30, %15
  %21 = load ptr, ptr %5, align 8, !tbaa !5
  %22 = icmp ne ptr %21, null
  br i1 %22, label %23, label %28

23:                                               ; preds = %20
  %24 = load ptr, ptr %5, align 8, !tbaa !5
  %25 = getelementptr inbounds %class.Node, ptr %24, i32 0, i32 1
  %26 = load ptr, ptr %25, align 8, !tbaa !9
  %27 = icmp ne ptr %26, null
  br label %28

28:                                               ; preds = %23, %20
  %29 = phi i1 [ false, %20 ], [ %27, %23 ]
  br i1 %29, label %30, label %39

30:                                               ; preds = %28
  %31 = load ptr, ptr %4, align 8, !tbaa !5
  %32 = getelementptr inbounds %class.Node, ptr %31, i32 0, i32 1
  %33 = load ptr, ptr %32, align 8, !tbaa !9
  store ptr %33, ptr %4, align 8, !tbaa !5
  %34 = load ptr, ptr %5, align 8, !tbaa !5
  %35 = getelementptr inbounds %class.Node, ptr %34, i32 0, i32 1
  %36 = load ptr, ptr %35, align 8, !tbaa !9
  %37 = getelementptr inbounds %class.Node, ptr %36, i32 0, i32 1
  %38 = load ptr, ptr %37, align 8, !tbaa !9
  store ptr %38, ptr %5, align 8, !tbaa !5
  br label %20, !llvm.loop !12

39:                                               ; preds = %28
  %40 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %40, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  br label %41

41:                                               ; preds = %39, %13
  %42 = load ptr, ptr %2, align 8
  ret ptr %42
}

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 %.preheader

.preheader:                                       ; preds = %3, %9
  %.018 = phi ptr [ %13, %9 ], [ %5, %3 ]
  %.01117 = phi ptr [ %11, %9 ], [ %0, %3 ]
  %7 = getelementptr inbounds i8, ptr %.018, i64 8
  %8 = load ptr, ptr %7, align 8, !tbaa !5
  %.not16 = icmp eq ptr %8, null
  br i1 %.not16, label %.critedge, label %9

9:                                                ; preds = %.preheader
  %10 = getelementptr inbounds i8, ptr %.01117, i64 8
  %11 = load ptr, ptr %10, align 8, !tbaa !5
  %12 = getelementptr inbounds i8, ptr %8, i64 8
  %13 = load ptr, ptr %12, align 8, !tbaa !5
  %.not = icmp eq ptr %13, null
  br i1 %.not, label %.critedge, label %.preheader, !llvm.loop !11

.critedge:                                        ; preds = %.preheader, %9, %1, %3
  %.012 = phi ptr [ %0, %3 ], [ null, %1 ], [ %11, %9 ], [ %.01117, %.preheader ]
  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,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass