; LLVM IR from priyankchheda/algorithms :: _other_languages/cpp/LinkedList (findMiddle)

; 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.LinkedList::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: mustprogress uwtable
define dso_local noundef i32 @_Z22findMiddle_UsingLengthPN10LinkedList10LinkedListIiEE(ptr noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = call noundef ptr @_ZN10LinkedList10LinkedListIiE7getHeadEv(ptr noundef nonnull align 8 dereferenceable(8) %9)
  store ptr %10, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  %11 = load ptr, ptr %3, align 8, !tbaa !5
  %12 = call noundef i32 @_ZN10LinkedList10LinkedListIiE9getLengthEv(ptr noundef nonnull align 8 dereferenceable(8) %11)
  store i32 %12, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #3
  %13 = load i32, ptr %5, align 4, !tbaa !9
  %14 = sdiv i32 %13, 2
  store i32 %14, ptr %6, align 4, !tbaa !9
  %15 = load ptr, ptr %4, align 8, !tbaa !5
  %16 = icmp eq ptr %15, null
  br i1 %16, label %17, label %18

17:                                               ; preds = %1
  store i32 -1, ptr %2, align 4
  store i32 1, ptr %7, align 4
  br label %35

18:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #3
  store i32 0, ptr %8, align 4, !tbaa !9
  br label %19

19:                                               ; preds = %28, %18
  %20 = load i32, ptr %8, align 4, !tbaa !9
  %21 = load i32, ptr %6, align 4, !tbaa !9
  %22 = icmp slt i32 %20, %21
  br i1 %22, label %24, label %23

23:                                               ; preds = %19
  store i32 2, ptr %7, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #3
  br label %31

24:                                               ; preds = %19
  %25 = load ptr, ptr %4, align 8, !tbaa !5
  %26 = getelementptr inbounds %"struct.LinkedList::Node", ptr %25, i32 0, i32 1
  %27 = load ptr, ptr %26, align 8, !tbaa !11
  store ptr %27, ptr %4, align 8, !tbaa !5
  br label %28

28:                                               ; preds = %24
  %29 = load i32, ptr %8, align 4, !tbaa !9
  %30 = add nsw i32 %29, 1
  store i32 %30, ptr %8, align 4, !tbaa !9
  br label %19, !llvm.loop !13

31:                                               ; preds = %23
  %32 = load ptr, ptr %4, align 8, !tbaa !5
  %33 = getelementptr inbounds %"struct.LinkedList::Node", ptr %32, i32 0, i32 0
  %34 = load i32, ptr %33, align 8, !tbaa !15
  store i32 %34, ptr %2, align 4
  store i32 1, ptr %7, align 4
  br label %35

35:                                               ; preds = %31, %17
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  %36 = load i32, ptr %2, align 4
  ret i32 %36
}

; 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
declare dso_local noundef ptr @_ZN10LinkedList10LinkedListIiE7getHeadEv(ptr noundef nonnull align 8 dereferenceable(8)) #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef i32 @_ZN10LinkedList10LinkedListIiE9getLengthEv(ptr noundef nonnull align 8 dereferenceable(8)) #2 align 2

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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 = { 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 #3 = { 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, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!12, !6, i64 8}
!12 = !{!"_ZTSN10LinkedList4NodeIiEE", !10, i64 0, !6, i64 8}
!13 = distinct !{!13, !14}
!14 = !{!"llvm.loop.mustprogress"}
!15 = !{!12, !10, i64 0}


; 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 nounwind uwtable
define dso_local noundef i32 @_Z22findMiddle_UsingLengthPN10LinkedList10LinkedListIiEE(ptr noundef nonnull %0) local_unnamed_addr #0 {
  %2 = tail call noundef ptr @_ZN10LinkedList10LinkedListIiE7getHeadEv(ptr noundef nonnull align 8 dereferenceable(8) %0)
  %3 = tail call noundef i32 @_ZN10LinkedList10LinkedListIiE9getLengthEv(ptr noundef nonnull align 8 dereferenceable(8) %0)
  %4 = sdiv i32 %3, 2
  %5 = icmp eq ptr %2, null
  br i1 %5, label %28, label %.preheader

.preheader:                                       ; preds = %1
  %6 = icmp sgt i32 %3, 1
  br i1 %6, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %.preheader
  %7 = add nsw i32 %4, -1
  %xtraiter = and i32 %4, 7
  %8 = icmp ult i32 %7, 7
  br i1 %8, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i32 %4, 1073741816
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %.lcssa.ph = phi ptr [ poison, %.lr.ph.preheader ], [ %27, %.lr.ph ]
  %.01012.unr = phi ptr [ %2, %.lr.ph.preheader ], [ %27, %.lr.ph ]
  %lcmp.mod.not = icmp eq i32 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil
  %.01012.epil = phi ptr [ %10, %.lr.ph.epil ], [ %.01012.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %9 = getelementptr inbounds i8, ptr %.01012.epil, i64 8
  %10 = load ptr, ptr %9, align 8, !tbaa !5
  %epil.iter.next = add i32 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i32 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge, label %.lr.ph.epil, !llvm.loop !11

._crit_edge:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil, %.preheader
  %.010.lcssa = phi ptr [ %2, %.preheader ], [ %.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %10, %.lr.ph.epil ]
  %11 = load i32, ptr %.010.lcssa, align 8, !tbaa !13
  br label %28

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %.01012 = phi ptr [ %2, %.lr.ph.preheader.new ], [ %27, %.lr.ph ]
  %niter = phi i32 [ 0, %.lr.ph.preheader.new ], [ %niter.next.7, %.lr.ph ]
  %12 = getelementptr inbounds i8, ptr %.01012, i64 8
  %13 = load ptr, ptr %12, align 8, !tbaa !5
  %14 = getelementptr inbounds i8, ptr %13, i64 8
  %15 = load ptr, ptr %14, align 8, !tbaa !5
  %16 = getelementptr inbounds i8, ptr %15, i64 8
  %17 = load ptr, ptr %16, align 8, !tbaa !5
  %18 = getelementptr inbounds i8, ptr %17, i64 8
  %19 = load ptr, ptr %18, align 8, !tbaa !5
  %20 = getelementptr inbounds i8, ptr %19, i64 8
  %21 = load ptr, ptr %20, align 8, !tbaa !5
  %22 = getelementptr inbounds i8, ptr %21, i64 8
  %23 = load ptr, ptr %22, align 8, !tbaa !5
  %24 = getelementptr inbounds i8, ptr %23, i64 8
  %25 = load ptr, ptr %24, align 8, !tbaa !5
  %26 = getelementptr inbounds i8, ptr %25, i64 8
  %27 = load ptr, ptr %26, align 8, !tbaa !5
  %niter.next.7 = add i32 %niter, 8
  %niter.ncmp.7 = icmp eq i32 %niter.next.7, %unroll_iter
  br i1 %niter.ncmp.7, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !14

28:                                               ; preds = %1, %._crit_edge
  %.09 = phi i32 [ %11, %._crit_edge ], [ -1, %1 ]
  ret i32 %.09
}

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef ptr @_ZN10LinkedList10LinkedListIiE7getHeadEv(ptr noundef nonnull align 8 dereferenceable(8)) local_unnamed_addr #0 align 2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef i32 @_ZN10LinkedList10LinkedListIiE9getLengthEv(ptr noundef nonnull align 8 dereferenceable(8)) local_unnamed_addr #0 align 2

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" }

!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 = !{!"_ZTSN10LinkedList4NodeIiEE", !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.unroll.disable"}
!13 = !{!6, !7, i64 0}
!14 = distinct !{!14, !15}
!15 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass