; LLVM IR from ahampriyanshu/algo-ds-101 :: Data-Structures/LinkedList/Singly_Linked_List/Delete_Kth_Node_From_End/Delete_Kth_eb8d8d8a (Z10countNodesP4node)

; 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 { i64, 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 i64 @_Z10countNodesP4node(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca i64, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #2
  %5 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %5, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  store i64 1, ptr %4, align 8, !tbaa !9
  %6 = load ptr, ptr %2, align 8, !tbaa !5
  %7 = icmp ne ptr %6, null
  br i1 %7, label %8, label %21

8:                                                ; preds = %1
  br label %9

9:                                                ; preds = %14, %8
  %10 = load ptr, ptr %3, align 8, !tbaa !5
  %11 = getelementptr inbounds %struct.node, ptr %10, i32 0, i32 1
  %12 = load ptr, ptr %11, align 8, !tbaa !11
  %13 = icmp ne ptr %12, null
  br i1 %13, label %14, label %20

14:                                               ; preds = %9
  %15 = load ptr, ptr %3, align 8, !tbaa !5
  %16 = getelementptr inbounds %struct.node, ptr %15, i32 0, i32 1
  %17 = load ptr, ptr %16, align 8, !tbaa !11
  store ptr %17, ptr %3, align 8, !tbaa !5
  %18 = load i64, ptr %4, align 8, !tbaa !9
  %19 = add nsw i64 %18, 1
  store i64 %19, ptr %4, align 8, !tbaa !9
  br label %9, !llvm.loop !13

20:                                               ; preds = %9
  br label %21

21:                                               ; preds = %20, %1
  %22 = load i64, ptr %4, align 8, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #2
  ret i64 %22
}

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 = !{!"long long", !7, i64 0}
!11 = !{!12, !6, i64 8}
!12 = !{!"_ZTS4node", !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 willreturn memory(read, inaccessiblemem: none) uwtable
define dso_local noundef i64 @_Z10countNodesP4node(ptr noundef readonly %0) local_unnamed_addr #0 {
  %.not = icmp eq ptr %0, null
  br i1 %.not, label %.loopexit, label %.preheader

.preheader:                                       ; preds = %1, %.preheader
  %.05 = phi ptr [ %3, %.preheader ], [ %0, %1 ]
  %.0 = phi i64 [ %4, %.preheader ], [ 1, %1 ]
  %2 = getelementptr inbounds i8, ptr %.05, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !5
  %.not8 = icmp eq ptr %3, null
  %4 = add nuw nsw i64 %.0, 1
  br i1 %.not8, label %.loopexit, label %.preheader, !llvm.loop !11

.loopexit:                                        ; preds = %.preheader, %1
  %.1 = phi i64 [ 1, %1 ], [ %.0, %.preheader ]
  ret i64 %.1
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn 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, !10, i64 8}
!6 = !{!"_ZTS4node", !7, i64 0, !10, i64 8}
!7 = !{!"long long", !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"}


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