; 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 @_Z28findMiddle_UsingOddIncrementPN10LinkedList10LinkedListIiEE(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 ptr, align 8
  %7 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  %9 = call noundef ptr @_ZN10LinkedList10LinkedListIiE7getHeadEv(ptr noundef nonnull align 8 dereferenceable(8) %8)
  store ptr %9, ptr %4, align 8, !tbaa !5
  %10 = load ptr, ptr %4, align 8, !tbaa !5
  %11 = icmp eq ptr %10, null
  br i1 %11, label %12, label %13

12:                                               ; preds = %1
  store i32 -1, ptr %2, align 4
  store i32 1, ptr %5, align 4
  br label %36

13:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #3
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %14, ptr %6, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #3
  store i32 0, ptr %7, align 4, !tbaa !9
  br label %15

15:                                               ; preds = %26, %13
  %16 = load ptr, ptr %4, align 8, !tbaa !5
  %17 = icmp ne ptr %16, null
  br i1 %17, label %18, label %32

18:                                               ; preds = %15
  %19 = load i32, ptr %7, align 4, !tbaa !9
  %20 = srem i32 %19, 2
  %21 = icmp ne i32 %20, 0
  br i1 %21, label %22, label %26

22:                                               ; preds = %18
  %23 = load ptr, ptr %6, align 8, !tbaa !5
  %24 = getelementptr inbounds %"struct.LinkedList::Node", ptr %23, i32 0, i32 1
  %25 = load ptr, ptr %24, align 8, !tbaa !11
  store ptr %25, ptr %6, align 8, !tbaa !5
  br label %26

26:                                               ; preds = %22, %18
  %27 = load ptr, ptr %4, align 8, !tbaa !5
  %28 = getelementptr inbounds %"struct.LinkedList::Node", ptr %27, i32 0, i32 1
  %29 = load ptr, ptr %28, align 8, !tbaa !11
  store ptr %29, ptr %4, align 8, !tbaa !5
  %30 = load i32, ptr %7, align 4, !tbaa !9
  %31 = add nsw i32 %30, 1
  store i32 %31, ptr %7, align 4, !tbaa !9
  br label %15, !llvm.loop !13

32:                                               ; preds = %15
  %33 = load ptr, ptr %6, align 8, !tbaa !5
  %34 = getelementptr inbounds %"struct.LinkedList::Node", ptr %33, i32 0, i32 0
  %35 = load i32, ptr %34, align 8, !tbaa !15
  store i32 %35, ptr %2, align 4
  store i32 1, ptr %5, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #3
  br label %36

36:                                               ; preds = %32, %12
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  %37 = load i32, ptr %2, align 4
  ret i32 %37
}

; 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

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 @_Z28findMiddle_UsingOddIncrementPN10LinkedList10LinkedListIiEE(ptr noundef nonnull %0) local_unnamed_addr #0 {
  %2 = tail call noundef ptr @_ZN10LinkedList10LinkedListIiE7getHeadEv(ptr noundef nonnull align 8 dereferenceable(8) %0)
  %3 = icmp eq ptr %2, null
  br i1 %3, label %14, label %.preheader

.preheader:                                       ; preds = %1, %8
  %.016 = phi i32 [ %11, %8 ], [ 0, %1 ]
  %.0915 = phi ptr [ %.1, %8 ], [ %2, %1 ]
  %.01014 = phi ptr [ %10, %8 ], [ %2, %1 ]
  %4 = and i32 %.016, 1
  %.not13 = icmp eq i32 %4, 0
  br i1 %.not13, label %8, label %5

5:                                                ; preds = %.preheader
  %6 = getelementptr inbounds i8, ptr %.0915, i64 8
  %7 = load ptr, ptr %6, align 8, !tbaa !5
  br label %8

8:                                                ; preds = %5, %.preheader
  %.1 = phi ptr [ %7, %5 ], [ %.0915, %.preheader ]
  %9 = getelementptr inbounds i8, ptr %.01014, i64 8
  %10 = load ptr, ptr %9, align 8, !tbaa !5
  %11 = add nuw nsw i32 %.016, 1
  %.not = icmp eq ptr %10, null
  br i1 %.not, label %12, label %.preheader, !llvm.loop !11

12:                                               ; preds = %8
  %13 = load i32, ptr %.1, align 8, !tbaa !13
  br label %14

14:                                               ; preds = %1, %12
  %.011 = phi i32 [ %13, %12 ], [ -1, %1 ]
  ret i32 %.011
}

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef ptr @_ZN10LinkedList10LinkedListIiE7getHeadEv(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.mustprogress"}
!13 = !{!6, !7, i64 0}


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