; LLVM IR from TheAlgorithms/C-Plus-Plus :: search/median_search2.ll (ZN6search14median_search210middleNodeEP8ListNode)

; 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: mustprogress nounwind uwtable
define dso_local noundef ptr @_ZN6search14median_search210middleNodeEP8ListNode(ptr noundef %0) #0 {
  %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 ne ptr %6, null
  br i1 %7, label %9, label %8

8:                                                ; preds = %1
  store ptr null, ptr %2, align 8
  br label %47

9:                                                ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  store ptr null, 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 %4, align 8, !tbaa !5
  store ptr %10, ptr %5, align 8, !tbaa !5
  br label %11

11:                                               ; preds = %25, %9
  %12 = load ptr, ptr %4, align 8, !tbaa !5
  %13 = getelementptr inbounds %struct.ListNode, 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.ListNode, ptr %17, i32 0, i32 1
  %19 = load ptr, ptr %18, align 8, !tbaa !9
  %20 = getelementptr inbounds %struct.ListNode, 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 %5, align 8, !tbaa !5
  %27 = getelementptr inbounds %struct.ListNode, ptr %26, i32 0, i32 1
  %28 = load ptr, ptr %27, align 8, !tbaa !9
  store ptr %28, ptr %5, align 8, !tbaa !5
  %29 = load ptr, ptr %4, align 8, !tbaa !5
  %30 = getelementptr inbounds %struct.ListNode, ptr %29, i32 0, i32 1
  %31 = load ptr, ptr %30, align 8, !tbaa !9
  %32 = getelementptr inbounds %struct.ListNode, ptr %31, i32 0, i32 1
  %33 = load ptr, ptr %32, align 8, !tbaa !9
  store ptr %33, ptr %4, 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.ListNode, ptr %35, i32 0, i32 1
  %37 = load ptr, ptr %36, align 8, !tbaa !9
  %38 = icmp ne ptr %37, null
  br i1 %38, label %39, label %43

39:                                               ; preds = %34
  %40 = load ptr, ptr %5, align 8, !tbaa !5
  %41 = getelementptr inbounds %struct.ListNode, ptr %40, i32 0, i32 1
  %42 = load ptr, ptr %41, align 8, !tbaa !9
  br label %45

43:                                               ; preds = %34
  %44 = load ptr, ptr %5, align 8, !tbaa !5
  br label %45

45:                                               ; preds = %43, %39
  %46 = phi ptr [ %42, %39 ], [ %44, %43 ]
  store ptr %46, 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 %47

47:                                               ; preds = %45, %8
  %48 = load ptr, ptr %2, align 8
  ret ptr %48
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

attributes #0 = { 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 #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 = !{!"_ZTS8ListNode", !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 @_ZN6search14median_search210middleNodeEP8ListNode(ptr noundef readonly %0) local_unnamed_addr #0 {
  %.not = icmp eq ptr %0, null
  br i1 %.not, label %.critedge.thread, label %.preheader

.preheader:                                       ; preds = %1
  %2 = getelementptr inbounds i8, ptr %0, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !5
  %.not1519 = icmp eq ptr %3, null
  br i1 %.not1519, label %.critedge.thread, label %.lr.ph

.lr.ph:                                           ; preds = %.preheader, %9
  %4 = phi ptr [ %11, %9 ], [ %3, %.preheader ]
  %.020 = phi ptr [ %8, %9 ], [ %0, %.preheader ]
  %5 = getelementptr inbounds i8, ptr %4, i64 8
  %6 = load ptr, ptr %5, align 8, !tbaa !5
  %.not16 = icmp eq ptr %6, null
  %7 = getelementptr inbounds i8, ptr %.020, i64 8
  %8 = load ptr, ptr %7, align 8, !tbaa !5
  br i1 %.not16, label %.critedge.thread, label %9

9:                                                ; preds = %.lr.ph
  %10 = getelementptr inbounds i8, ptr %6, i64 8
  %11 = load ptr, ptr %10, align 8, !tbaa !5
  %.not15 = icmp eq ptr %11, null
  br i1 %.not15, label %.critedge.thread, label %.lr.ph, !llvm.loop !11

.critedge.thread:                                 ; preds = %9, %.lr.ph, %.preheader, %1
  %.011 = phi ptr [ null, %1 ], [ %0, %.preheader ], [ %8, %.lr.ph ], [ %8, %9 ]
  ret ptr %.011
}

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 = !{!"_ZTS8ListNode", !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,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass