; LLVM IR from JessonYue/LeetCodeLearning :: Array/caiweixiong/c (homework_024)

; 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: 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: nounwind uwtable
define dso_local ptr @findMiddleElement(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 %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #2
  store ptr null, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %6 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %6, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %7 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %7, ptr %5, align 8, !tbaa !5
  br label %8

8:                                                ; preds = %18, %1
  %9 = load ptr, ptr %5, align 8, !tbaa !5
  %10 = icmp ne ptr %9, null
  br i1 %10, label %11, label %16

11:                                               ; preds = %8
  %12 = load ptr, ptr %5, 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 label %16

16:                                               ; preds = %11, %8
  %17 = phi i1 [ false, %8 ], [ %15, %11 ]
  br i1 %17, label %18, label %28

18:                                               ; preds = %16
  %19 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %19, ptr %3, align 8, !tbaa !5
  %20 = load ptr, ptr %4, align 8, !tbaa !5
  %21 = getelementptr inbounds %struct.ListNode, ptr %20, i32 0, i32 1
  %22 = load ptr, ptr %21, align 8, !tbaa !9
  store ptr %22, ptr %4, align 8, !tbaa !5
  %23 = load ptr, ptr %5, align 8, !tbaa !5
  %24 = getelementptr inbounds %struct.ListNode, ptr %23, i32 0, i32 1
  %25 = load ptr, ptr %24, align 8, !tbaa !9
  %26 = getelementptr inbounds %struct.ListNode, ptr %25, i32 0, i32 1
  %27 = load ptr, ptr %26, align 8, !tbaa !9
  store ptr %27, ptr %5, align 8, !tbaa !5
  br label %8, !llvm.loop !12

28:                                               ; preds = %16
  %29 = load ptr, ptr %3, align 8, !tbaa !5
  %30 = icmp ne ptr %29, null
  br i1 %30, label %31, label %34

31:                                               ; preds = %28
  %32 = load ptr, ptr %3, align 8, !tbaa !5
  %33 = getelementptr inbounds %struct.ListNode, ptr %32, i32 0, i32 1
  store ptr null, ptr %33, align 8, !tbaa !9
  br label %34

34:                                               ; preds = %31, %28
  %35 = load ptr, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #2
  ret ptr %35
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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/C++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"ListNode", !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: nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local ptr @findMiddleElement(ptr noundef %0) local_unnamed_addr #0 {
  %.not15 = icmp eq ptr %0, null
  br i1 %.not15, label %.critedge.thread, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %1
  %2 = getelementptr inbounds i8, ptr %0, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !5
  %.not1337 = icmp eq ptr %3, null
  br i1 %.not1337, label %.critedge, label %.lr.ph39

.lr.ph:                                           ; preds = %.lr.ph39
  %4 = getelementptr inbounds i8, ptr %10, i64 8
  %5 = load ptr, ptr %4, align 8, !tbaa !5
  %.not13 = icmp eq ptr %5, null
  br i1 %.not13, label %.critedge, label %.lr.ph39, !llvm.loop !11

.lr.ph39:                                         ; preds = %.lr.ph.preheader, %.lr.ph
  %6 = phi ptr [ %5, %.lr.ph ], [ %3, %.lr.ph.preheader ]
  %.0101738 = phi ptr [ %8, %.lr.ph ], [ %0, %.lr.ph.preheader ]
  %7 = getelementptr inbounds i8, ptr %.0101738, i64 8
  %8 = load ptr, ptr %7, align 8, !tbaa !5
  %9 = getelementptr inbounds i8, ptr %6, i64 8
  %10 = load ptr, ptr %9, align 8, !tbaa !5
  %.not = icmp eq ptr %10, null
  br i1 %.not, label %.critedge.thread27, label %.lr.ph, !llvm.loop !11

.critedge:                                        ; preds = %.lr.ph, %.lr.ph.preheader
  %.01017.lcssa = phi ptr [ %0, %.lr.ph.preheader ], [ %8, %.lr.ph ]
  %.01116.lcssa = phi ptr [ null, %.lr.ph.preheader ], [ %.0101738, %.lr.ph ]
  %.not14 = icmp eq ptr %.01116.lcssa, null
  br i1 %.not14, label %.critedge.thread, label %.critedge.thread27

.critedge.thread27:                               ; preds = %.lr.ph39, %.critedge
  %.010.lcssa32 = phi ptr [ %.01017.lcssa, %.critedge ], [ %8, %.lr.ph39 ]
  %.011.lcssa31 = phi ptr [ %.01116.lcssa, %.critedge ], [ %.0101738, %.lr.ph39 ]
  %11 = getelementptr inbounds i8, ptr %.011.lcssa31, i64 8
  store ptr null, ptr %11, align 8, !tbaa !5
  br label %.critedge.thread

.critedge.thread:                                 ; preds = %1, %.critedge.thread27, %.critedge
  %.010.lcssa26 = phi ptr [ %.010.lcssa32, %.critedge.thread27 ], [ %.01017.lcssa, %.critedge ], [ null, %1 ]
  ret ptr %.010.lcssa26
}

attributes #0 = { 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 = !{!"ListNode", !7, i64 0, !10, i64 8}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/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,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass