; LLVM IR from KishanBGajera/2024-366-Days-Of-DSA :: Algorithms/Two Pointers - Hare and Tortoise Algorithm/Cycle or Loop Detection (addToLinkedList)

; 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 = type { ptr, i32 }
%struct.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: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind uwtable
declare dso_local void @addedToSLL(ptr noundef) #1

; Function Attrs: nounwind uwtable
define dso_local void @addToLinkedList(ptr noundef %0, ptr noundef %1) #1 {
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  store ptr %1, ptr %4, align 8, !tbaa !5
  %6 = load ptr, ptr %3, align 8, !tbaa !5
  %7 = getelementptr inbounds %struct.LinkedList, ptr %6, i32 0, i32 0
  %8 = load ptr, ptr %7, align 8, !tbaa !9
  %9 = icmp ne ptr %8, null
  br i1 %9, label %14, label %10

10:                                               ; preds = %2
  %11 = load ptr, ptr %4, align 8, !tbaa !5
  %12 = load ptr, ptr %3, align 8, !tbaa !5
  %13 = getelementptr inbounds %struct.LinkedList, ptr %12, i32 0, i32 0
  store ptr %11, ptr %13, align 8, !tbaa !9
  br label %31

14:                                               ; preds = %2
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %15 = load ptr, ptr %3, align 8, !tbaa !5
  %16 = getelementptr inbounds %struct.LinkedList, ptr %15, i32 0, i32 0
  %17 = load ptr, ptr %16, align 8, !tbaa !9
  store ptr %17, ptr %5, align 8, !tbaa !5
  br label %18

18:                                               ; preds = %23, %14
  %19 = load ptr, ptr %5, align 8, !tbaa !5
  %20 = getelementptr inbounds %struct.Node, ptr %19, i32 0, i32 1
  %21 = load ptr, ptr %20, align 8, !tbaa !12
  %22 = icmp ne ptr %21, null
  br i1 %22, label %23, label %27

23:                                               ; preds = %18
  %24 = load ptr, ptr %5, align 8, !tbaa !5
  %25 = getelementptr inbounds %struct.Node, ptr %24, i32 0, i32 1
  %26 = load ptr, ptr %25, align 8, !tbaa !12
  store ptr %26, ptr %5, align 8, !tbaa !5
  br label %18, !llvm.loop !14

27:                                               ; preds = %18
  %28 = load ptr, ptr %4, align 8, !tbaa !5
  %29 = load ptr, ptr %5, align 8, !tbaa !5
  %30 = getelementptr inbounds %struct.Node, ptr %29, i32 0, i32 1
  store ptr %28, ptr %30, align 8, !tbaa !12
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  br label %31

31:                                               ; preds = %27, %10
  %32 = load ptr, ptr %3, align 8, !tbaa !5
  call void @addedToSLL(ptr noundef %32)
  ret void
}

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 0}
!10 = !{!"LinkedList", !6, i64 0, !11, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = !{!13, !6, i64 8}
!13 = !{!"Node", !11, i64 0, !6, i64 8}
!14 = distinct !{!14, !15}
!15 = !{!"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: nounwind uwtable
declare dso_local void @addedToSLL(ptr noundef) local_unnamed_addr #0

; Function Attrs: nounwind uwtable
define dso_local void @addToLinkedList(ptr noundef %0, ptr noundef %1) local_unnamed_addr #0 {
  %3 = load ptr, ptr %0, align 8, !tbaa !5
  %.not = icmp eq ptr %3, null
  br i1 %.not, label %8, label %.preheader

.preheader:                                       ; preds = %2, %.preheader
  %.0 = phi ptr [ %5, %.preheader ], [ %3, %2 ]
  %4 = getelementptr inbounds i8, ptr %.0, i64 8
  %5 = load ptr, ptr %4, align 8, !tbaa !11
  %.not11 = icmp eq ptr %5, null
  br i1 %.not11, label %6, label %.preheader, !llvm.loop !13

6:                                                ; preds = %.preheader
  %7 = getelementptr inbounds i8, ptr %.0, i64 8
  br label %8

8:                                                ; preds = %2, %6
  %.sink = phi ptr [ %7, %6 ], [ %0, %2 ]
  store ptr %1, ptr %.sink, align 8, !tbaa !15
  tail call void @addedToSLL(ptr noundef nonnull %0)
  ret void
}

attributes #0 = { 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, !7, i64 0}
!6 = !{!"LinkedList", !7, i64 0, !10, i64 8}
!7 = !{!"any pointer", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = !{!"int", !8, i64 0}
!11 = !{!12, !7, i64 8}
!12 = !{!"Node", !10, i64 0, !7, i64 8}
!13 = distinct !{!13, !14}
!14 = !{!"llvm.loop.mustprogress"}
!15 = !{!7, !7, i64 0}


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