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

; 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
define dso_local ptr @searchNode(ptr noundef %0, i32 noundef %1) #1 {
  %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 %4, align 8, !tbaa !5
  store i32 %1, ptr %5, align 4, !tbaa !9
  %8 = load ptr, ptr %4, align 8, !tbaa !5
  %9 = getelementptr inbounds %struct.LinkedList, ptr %8, i32 0, i32 0
  %10 = load ptr, ptr %9, align 8, !tbaa !11
  %11 = icmp ne ptr %10, null
  br i1 %11, label %13, label %12

12:                                               ; preds = %2
  store ptr null, ptr %3, align 8
  br label %42

13:                                               ; preds = %2
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  %15 = getelementptr inbounds %struct.LinkedList, ptr %14, i32 0, i32 0
  %16 = load ptr, ptr %15, align 8, !tbaa !11
  store ptr %16, ptr %6, align 8, !tbaa !5
  br label %17

17:                                               ; preds = %28, %13
  %18 = load ptr, ptr %6, align 8, !tbaa !5
  %19 = icmp ne ptr %18, null
  br i1 %19, label %20, label %26

20:                                               ; preds = %17
  %21 = load ptr, ptr %6, align 8, !tbaa !5
  %22 = getelementptr inbounds %struct.Node, ptr %21, i32 0, i32 0
  %23 = load i32, ptr %22, align 8, !tbaa !13
  %24 = load i32, ptr %5, align 4, !tbaa !9
  %25 = icmp ne i32 %23, %24
  br label %26

26:                                               ; preds = %20, %17
  %27 = phi i1 [ false, %17 ], [ %25, %20 ]
  br i1 %27, label %28, label %32

28:                                               ; preds = %26
  %29 = load ptr, ptr %6, align 8, !tbaa !5
  %30 = getelementptr inbounds %struct.Node, ptr %29, i32 0, i32 1
  %31 = load ptr, ptr %30, align 8, !tbaa !15
  store ptr %31, ptr %6, align 8, !tbaa !5
  br label %17, !llvm.loop !16

32:                                               ; preds = %26
  %33 = load ptr, ptr %6, align 8, !tbaa !5
  %34 = getelementptr inbounds %struct.Node, ptr %33, i32 0, i32 0
  %35 = load i32, ptr %34, align 8, !tbaa !13
  %36 = load i32, ptr %5, align 4, !tbaa !9
  %37 = icmp eq i32 %35, %36
  br i1 %37, label %38, label %40

38:                                               ; preds = %32
  %39 = load ptr, ptr %6, align 8, !tbaa !5
  store ptr %39, ptr %3, align 8
  store i32 1, ptr %7, align 4
  br label %41

40:                                               ; preds = %32
  store ptr null, ptr %3, align 8
  store i32 1, ptr %7, align 4
  br label %41

41:                                               ; preds = %40, %38
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  br label %42

42:                                               ; preds = %41, %12
  %43 = load ptr, ptr %3, align 8
  ret ptr %43
}

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, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!12, !6, i64 0}
!12 = !{!"LinkedList", !6, i64 0, !10, i64 8}
!13 = !{!14, !10, i64 0}
!14 = !{!"Node", !10, i64 0, !6, i64 8}
!15 = !{!14, !6, i64 8}
!16 = distinct !{!16, !17}
!17 = !{!"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 noundef ptr @searchNode(ptr nocapture noundef readonly %0, i32 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 %.critedge, label %.preheader

.preheader:                                       ; preds = %2, %5
  %.013 = phi ptr [ %7, %5 ], [ %3, %2 ]
  %4 = load i32, ptr %.013, align 8, !tbaa !11
  %.not12 = icmp eq i32 %4, %1
  br i1 %.not12, label %.critedge, label %5

5:                                                ; preds = %.preheader
  %6 = getelementptr inbounds i8, ptr %.013, i64 8
  %7 = load ptr, ptr %6, align 8, !tbaa !13
  %.not11 = icmp eq ptr %7, null
  br i1 %.not11, label %.critedge, label %.preheader, !llvm.loop !14

.critedge:                                        ; preds = %5, %.preheader, %2
  %.1 = phi ptr [ null, %2 ], [ %.013, %.preheader ], [ null, %5 ]
  ret ptr %.1
}

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, !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, !10, i64 0}
!12 = !{!"Node", !10, i64 0, !7, i64 8}
!13 = !{!12, !7, i64 8}
!14 = distinct !{!14, !15}
!15 = !{!"llvm.loop.mustprogress"}


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