; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 36. C Programs (single_linkedlist)

; 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.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 @delete_from_start(ptr noundef) #1

; Function Attrs: nounwind uwtable
define dso_local void @delete_from_position(ptr noundef %0, i32 noundef %1) #1 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca ptr, align 8
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  %9 = load ptr, ptr %8, align 8, !tbaa !5
  store ptr %9, ptr %5, align 8, !tbaa !5
  %10 = load i32, ptr %4, align 4, !tbaa !9
  %11 = icmp eq i32 %10, 1
  br i1 %11, label %12, label %14

12:                                               ; preds = %2
  %13 = load ptr, ptr %3, align 8, !tbaa !5
  call void @delete_from_start(ptr noundef %13)
  store i32 1, ptr %6, align 4
  br label %41

14:                                               ; preds = %2
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #2
  store i32 2, ptr %7, align 4, !tbaa !9
  br label %15

15:                                               ; preds = %30, %14
  %16 = load i32, ptr %7, align 4, !tbaa !9
  %17 = load i32, ptr %4, align 4, !tbaa !9
  %18 = icmp slt i32 %16, %17
  br i1 %18, label %20, label %19

19:                                               ; preds = %15
  store i32 2, ptr %6, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #2
  br label %33

20:                                               ; preds = %15
  %21 = load ptr, ptr %5, align 8, !tbaa !5
  %22 = getelementptr inbounds %struct.node, ptr %21, i32 0, i32 1
  %23 = load ptr, ptr %22, align 8, !tbaa !11
  %24 = icmp ne ptr %23, null
  br i1 %24, label %25, label %29

25:                                               ; preds = %20
  %26 = load ptr, ptr %5, align 8, !tbaa !5
  %27 = getelementptr inbounds %struct.node, ptr %26, i32 0, i32 1
  %28 = load ptr, ptr %27, align 8, !tbaa !11
  store ptr %28, ptr %5, align 8, !tbaa !5
  br label %29

29:                                               ; preds = %25, %20
  br label %30

30:                                               ; preds = %29
  %31 = load i32, ptr %7, align 4, !tbaa !9
  %32 = add nsw i32 %31, 1
  store i32 %32, ptr %7, align 4, !tbaa !9
  br label %15, !llvm.loop !13

33:                                               ; preds = %19
  %34 = load ptr, ptr %5, align 8, !tbaa !5
  %35 = getelementptr inbounds %struct.node, ptr %34, i32 0, i32 1
  %36 = load ptr, ptr %35, align 8, !tbaa !11
  %37 = getelementptr inbounds %struct.node, ptr %36, i32 0, i32 1
  %38 = load ptr, ptr %37, align 8, !tbaa !11
  %39 = load ptr, ptr %5, align 8, !tbaa !5
  %40 = getelementptr inbounds %struct.node, ptr %39, i32 0, i32 1
  store ptr %38, ptr %40, align 8, !tbaa !11
  store i32 0, ptr %6, align 4
  br label %41

41:                                               ; preds = %33, %12
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  %42 = load i32, ptr %6, align 4
  switch i32 %42, label %44 [
    i32 0, label %43
    i32 1, label %43
  ]

43:                                               ; preds = %41, %41
  ret void

44:                                               ; preds = %41
  unreachable
}

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 8}
!12 = !{!"node", !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: nounwind uwtable
declare dso_local void @delete_from_start(ptr noundef) local_unnamed_addr #0

; Function Attrs: nounwind uwtable
define dso_local void @delete_from_position(ptr noundef %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = icmp eq i32 %1, 1
  br i1 %3, label %4, label %5

4:                                                ; preds = %2
  tail call void @delete_from_start(ptr noundef %0)
  br label %25

5:                                                ; preds = %2
  %6 = load ptr, ptr %0, align 8, !tbaa !5
  %7 = icmp sgt i32 %1, 2
  br i1 %7, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %5
  %8 = add nsw i32 %1, -2
  %9 = add nsw i32 %1, -3
  %xtraiter = and i32 %8, 3
  %10 = icmp ult i32 %9, 3
  br i1 %10, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i32 %8, -4
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %spec.select.lcssa.ph = phi ptr [ poison, %.lr.ph.preheader ], [ %spec.select.3, %.lr.ph ]
  %.0912.unr = phi ptr [ %6, %.lr.ph.preheader ], [ %spec.select.3, %.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
  %.0912.epil = phi ptr [ %spec.select.epil, %.lr.ph.epil ], [ %.0912.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %11 = getelementptr inbounds i8, ptr %.0912.epil, i64 8
  %12 = load ptr, ptr %11, align 8, !tbaa !9
  %.not.epil = icmp eq ptr %12, null
  %spec.select.epil = select i1 %.not.epil, ptr %.0912.epil, ptr %12
  %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 !12

._crit_edge:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil, %5
  %.09.lcssa = phi ptr [ %6, %5 ], [ %spec.select.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %spec.select.epil, %.lr.ph.epil ]
  %13 = getelementptr inbounds i8, ptr %.09.lcssa, i64 8
  %14 = load ptr, ptr %13, align 8, !tbaa !9
  %15 = getelementptr inbounds i8, ptr %14, i64 8
  %16 = load ptr, ptr %15, align 8, !tbaa !9
  store ptr %16, ptr %13, align 8, !tbaa !9
  br label %25

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %.0912 = phi ptr [ %6, %.lr.ph.preheader.new ], [ %spec.select.3, %.lr.ph ]
  %niter = phi i32 [ 0, %.lr.ph.preheader.new ], [ %niter.next.3, %.lr.ph ]
  %17 = getelementptr inbounds i8, ptr %.0912, i64 8
  %18 = load ptr, ptr %17, align 8, !tbaa !9
  %.not = icmp eq ptr %18, null
  %spec.select = select i1 %.not, ptr %.0912, ptr %18
  %19 = getelementptr inbounds i8, ptr %spec.select, i64 8
  %20 = load ptr, ptr %19, align 8, !tbaa !9
  %.not.1 = icmp eq ptr %20, null
  %spec.select.1 = select i1 %.not.1, ptr %spec.select, ptr %20
  %21 = getelementptr inbounds i8, ptr %spec.select.1, i64 8
  %22 = load ptr, ptr %21, align 8, !tbaa !9
  %.not.2 = icmp eq ptr %22, null
  %spec.select.2 = select i1 %.not.2, ptr %spec.select.1, ptr %22
  %23 = getelementptr inbounds i8, ptr %spec.select.2, i64 8
  %24 = load ptr, ptr %23, align 8, !tbaa !9
  %.not.3 = icmp eq ptr %24, null
  %spec.select.3 = select i1 %.not.3, ptr %spec.select.2, ptr %24
  %niter.next.3 = add i32 %niter, 4
  %niter.ncmp.3 = icmp eq i32 %niter.next.3, %unroll_iter
  br i1 %niter.ncmp.3, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !14

25:                                               ; preds = %._crit_edge, %4
  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, !6, i64 0}
!6 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.unroll.disable"}
!14 = distinct !{!14, !15}
!15 = !{!"llvm.loop.mustprogress"}


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