; LLVM IR from afrozchakure/Competitive-Programming-Solutions :: HackerRank/Problem-Solving/DeleteANode.ll (Z10deleteNodeP20SinglyLinkedListNodei)

; 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"

%class.SinglyLinkedListNode = 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: mustprogress nounwind uwtable
define dso_local noundef ptr @_Z10deleteNodeP20SinglyLinkedListNodei(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
  %8 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store i32 %1, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  %9 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %9, ptr %6, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #2
  store i32 0, ptr %7, align 4, !tbaa !9
  %10 = load ptr, ptr %4, align 8, !tbaa !5
  %11 = icmp eq ptr %10, null
  br i1 %11, label %12, label %13

12:                                               ; preds = %2
  store ptr null, ptr %3, align 8
  store i32 1, ptr %8, align 4
  br label %42

13:                                               ; preds = %2
  %14 = load i32, ptr %5, align 4, !tbaa !9
  %15 = icmp eq i32 %14, 0
  br i1 %15, label %16, label %20

16:                                               ; preds = %13
  %17 = load ptr, ptr %4, align 8, !tbaa !5
  %18 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %17, i32 0, i32 1
  %19 = load ptr, ptr %18, align 8, !tbaa !11
  store ptr %19, ptr %4, align 8, !tbaa !5
  br label %40

20:                                               ; preds = %13
  br label %21

21:                                               ; preds = %26, %20
  %22 = load i32, ptr %7, align 4, !tbaa !9
  %23 = load i32, ptr %5, align 4, !tbaa !9
  %24 = sub nsw i32 %23, 1
  %25 = icmp slt i32 %22, %24
  br i1 %25, label %26, label %32

26:                                               ; preds = %21
  %27 = load ptr, ptr %6, align 8, !tbaa !5
  %28 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %27, i32 0, i32 1
  %29 = load ptr, ptr %28, align 8, !tbaa !11
  store ptr %29, ptr %6, 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 %21, !llvm.loop !13

32:                                               ; preds = %21
  %33 = load ptr, ptr %6, align 8, !tbaa !5
  %34 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %33, i32 0, i32 1
  %35 = load ptr, ptr %34, align 8, !tbaa !11
  %36 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %35, i32 0, i32 1
  %37 = load ptr, ptr %36, align 8, !tbaa !11
  %38 = load ptr, ptr %6, align 8, !tbaa !5
  %39 = getelementptr inbounds %class.SinglyLinkedListNode, ptr %38, i32 0, i32 1
  store ptr %37, ptr %39, align 8, !tbaa !11
  br label %40

40:                                               ; preds = %32, %16
  %41 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %41, ptr %3, align 8
  store i32 1, ptr %8, align 4
  br label %42

42:                                               ; preds = %40, %12
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  %43 = load ptr, ptr %3, align 8
  ret ptr %43
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!12, !6, i64 8}
!12 = !{!"_ZTS20SinglyLinkedListNode", !10, i64 0, !6, i64 8}
!13 = distinct !{!13, !14}
!14 = !{!"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: mustprogress nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local noundef ptr @_Z10deleteNodeP20SinglyLinkedListNodei(ptr noundef %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = icmp eq ptr %0, null
  br i1 %3, label %35, label %4

4:                                                ; preds = %2
  %5 = icmp eq i32 %1, 0
  br i1 %5, label %10, label %.preheader

.preheader:                                       ; preds = %4
  %6 = icmp sgt i32 %1, 1
  br i1 %6, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %.preheader
  %7 = add nsw i32 %1, -2
  %8 = add nsw i32 %1, -1
  %xtraiter = and i32 %8, 7
  %9 = icmp ult i32 %7, 7
  br i1 %9, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i32 %8, -8
  br label %.lr.ph

10:                                               ; preds = %4
  %11 = getelementptr inbounds i8, ptr %0, i64 8
  %12 = load ptr, ptr %11, align 8, !tbaa !5
  br label %35

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %.01115 = phi ptr [ %0, %.lr.ph.preheader.new ], [ %28, %.lr.ph ]
  %niter = phi i32 [ 0, %.lr.ph.preheader.new ], [ %niter.next.7, %.lr.ph ]
  %13 = getelementptr inbounds i8, ptr %.01115, i64 8
  %14 = load ptr, ptr %13, align 8, !tbaa !5
  %15 = getelementptr inbounds i8, ptr %14, i64 8
  %16 = load ptr, ptr %15, align 8, !tbaa !5
  %17 = getelementptr inbounds i8, ptr %16, i64 8
  %18 = load ptr, ptr %17, align 8, !tbaa !5
  %19 = getelementptr inbounds i8, ptr %18, i64 8
  %20 = load ptr, ptr %19, align 8, !tbaa !5
  %21 = getelementptr inbounds i8, ptr %20, i64 8
  %22 = load ptr, ptr %21, align 8, !tbaa !5
  %23 = getelementptr inbounds i8, ptr %22, i64 8
  %24 = load ptr, ptr %23, align 8, !tbaa !5
  %25 = getelementptr inbounds i8, ptr %24, i64 8
  %26 = load ptr, ptr %25, align 8, !tbaa !5
  %27 = getelementptr inbounds i8, ptr %26, i64 8
  %28 = load ptr, ptr %27, 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 !11

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %.lcssa.ph = phi ptr [ poison, %.lr.ph.preheader ], [ %28, %.lr.ph ]
  %.01115.unr = phi ptr [ %0, %.lr.ph.preheader ], [ %28, %.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
  %.01115.epil = phi ptr [ %30, %.lr.ph.epil ], [ %.01115.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %29 = getelementptr inbounds i8, ptr %.01115.epil, i64 8
  %30 = load ptr, ptr %29, 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 !13

._crit_edge:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil, %.preheader
  %.011.lcssa = phi ptr [ %0, %.preheader ], [ %.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %30, %.lr.ph.epil ]
  %31 = getelementptr inbounds i8, ptr %.011.lcssa, i64 8
  %32 = load ptr, ptr %31, align 8, !tbaa !5
  %33 = getelementptr inbounds i8, ptr %32, i64 8
  %34 = load ptr, ptr %33, align 8, !tbaa !5
  store ptr %34, ptr %31, align 8, !tbaa !5
  br label %35

35:                                               ; preds = %10, %._crit_edge, %2
  %.012 = phi ptr [ null, %2 ], [ %12, %10 ], [ %0, %._crit_edge ]
  ret ptr %.012
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind memory(readwrite, 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 = !{!"_ZTS20SinglyLinkedListNode", !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 = distinct !{!13, !14}
!14 = !{!"llvm.loop.unroll.disable"}


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