; LLVM IR from JessonYue/LeetCodeLearning :: Array/zhangjunwei/linked_list (isPalindrome_6_12)

; 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 @endOfFirstHalf(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #2
  %5 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %5, 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
  br label %7

7:                                                ; preds = %21, %1
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  %9 = getelementptr inbounds %struct.ListNode_, ptr %8, i32 0, i32 1
  %10 = load ptr, ptr %9, align 8, !tbaa !9
  %11 = icmp ne ptr %10, null
  br i1 %11, label %12, label %19

12:                                               ; preds = %7
  %13 = load ptr, ptr %3, align 8, !tbaa !5
  %14 = getelementptr inbounds %struct.ListNode_, ptr %13, i32 0, i32 1
  %15 = load ptr, ptr %14, align 8, !tbaa !9
  %16 = getelementptr inbounds %struct.ListNode_, ptr %15, i32 0, i32 1
  %17 = load ptr, ptr %16, align 8, !tbaa !9
  %18 = icmp ne ptr %17, null
  br label %19

19:                                               ; preds = %12, %7
  %20 = phi i1 [ false, %7 ], [ %18, %12 ]
  br i1 %20, label %21, label %30

21:                                               ; preds = %19
  %22 = load ptr, ptr %3, align 8, !tbaa !5
  %23 = getelementptr inbounds %struct.ListNode_, ptr %22, i32 0, i32 1
  %24 = load ptr, ptr %23, align 8, !tbaa !9
  %25 = getelementptr inbounds %struct.ListNode_, ptr %24, i32 0, i32 1
  %26 = load ptr, ptr %25, align 8, !tbaa !9
  store ptr %26, ptr %3, align 8, !tbaa !5
  %27 = load ptr, ptr %4, align 8, !tbaa !5
  %28 = getelementptr inbounds %struct.ListNode_, ptr %27, i32 0, i32 1
  %29 = load ptr, ptr %28, align 8, !tbaa !9
  store ptr %29, ptr %4, align 8, !tbaa !5
  br label %7, !llvm.loop !12

30:                                               ; preds = %19
  %31 = load ptr, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #2
  ret ptr %31
}

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(read, inaccessiblemem: none) uwtable
define dso_local ptr @endOfFirstHalf(ptr noundef readonly %0) local_unnamed_addr #0 {
  %2 = getelementptr inbounds i8, ptr %0, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !5
  %.not11 = icmp eq ptr %3, null
  br i1 %.not11, label %.critedge, label %.lr.ph

.lr.ph:                                           ; preds = %1, %7
  %4 = phi ptr [ %11, %7 ], [ %3, %1 ]
  %.012 = phi ptr [ %9, %7 ], [ %0, %1 ]
  %5 = getelementptr inbounds i8, ptr %4, i64 8
  %6 = load ptr, ptr %5, align 8, !tbaa !5
  %.not10 = icmp eq ptr %6, null
  br i1 %.not10, label %.critedge, label %7

7:                                                ; preds = %.lr.ph
  %8 = getelementptr inbounds i8, ptr %.012, i64 8
  %9 = load ptr, ptr %8, align 8, !tbaa !5
  %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 %.critedge, label %.lr.ph, !llvm.loop !11

.critedge:                                        ; preds = %.lr.ph, %7, %1
  %.0.lcssa = phi ptr [ %0, %1 ], [ %9, %7 ], [ %.012, %.lr.ph ]
  ret ptr %.0.lcssa
}

attributes #0 = { nofree norecurse nosync nounwind 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 = !{!"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: EarlyCSEPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass