; LLVM IR from AnneLivia/Competitive-Programming :: Data Structures/Linked List/Circular Linked List (Implemented With Struct)/circula_20172543 (backPP4Node)

; 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
declare void @free(ptr noundef) #1

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef zeroext i1 @_Z11remove_backPP4Node(ptr noundef %0) #2 {
  %2 = alloca i1, align 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
  %6 = load ptr, ptr %3, align 8, !tbaa !5
  %7 = icmp eq ptr %6, null
  br i1 %7, label %12, label %8

8:                                                ; preds = %1
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = load ptr, ptr %9, align 8, !tbaa !5
  %11 = icmp eq ptr %10, null
  br i1 %11, label %12, label %13

12:                                               ; preds = %8, %1
  store i1 false, ptr %2, align 1
  br label %43

13:                                               ; preds = %8
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  %15 = load ptr, ptr %14, align 8, !tbaa !5
  store ptr %15, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #3
  br label %16

16:                                               ; preds = %23, %13
  %17 = load ptr, ptr %4, align 8, !tbaa !5
  %18 = getelementptr inbounds %struct.Node, ptr %17, i32 0, i32 1
  %19 = load ptr, ptr %18, align 8, !tbaa !9
  %20 = load ptr, ptr %3, align 8, !tbaa !5
  %21 = load ptr, ptr %20, align 8, !tbaa !5
  %22 = icmp ne ptr %19, %21
  br i1 %22, label %23, label %28

23:                                               ; preds = %16
  %24 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %24, ptr %5, align 8, !tbaa !5
  %25 = load ptr, ptr %4, align 8, !tbaa !5
  %26 = getelementptr inbounds %struct.Node, ptr %25, i32 0, i32 1
  %27 = load ptr, ptr %26, align 8, !tbaa !9
  store ptr %27, ptr %4, align 8, !tbaa !5
  br label %16, !llvm.loop !12

28:                                               ; preds = %16
  %29 = load ptr, ptr %4, align 8, !tbaa !5
  %30 = load ptr, ptr %3, align 8, !tbaa !5
  %31 = load ptr, ptr %30, align 8, !tbaa !5
  %32 = icmp eq ptr %29, %31
  br i1 %32, label %33, label %35

33:                                               ; preds = %28
  %34 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr null, ptr %34, align 8, !tbaa !5
  br label %41

35:                                               ; preds = %28
  %36 = load ptr, ptr %4, align 8, !tbaa !5
  %37 = getelementptr inbounds %struct.Node, ptr %36, i32 0, i32 1
  %38 = load ptr, ptr %37, align 8, !tbaa !9
  %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 !9
  br label %41

41:                                               ; preds = %35, %33
  %42 = load ptr, ptr %4, align 8, !tbaa !5
  call void @free(ptr noundef %42) #3
  store ptr null, ptr %4, align 8, !tbaa !5
  store i1 true, ptr %2, align 1
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  br label %43

43:                                               ; preds = %41, %12
  %44 = load i1, ptr %2, align 1
  ret i1 %44
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { nounwind "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 = { 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 #3 = { 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, !6, i64 8}
!10 = !{!"_ZTS4Node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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 nounwind willreturn allockind("free") memory(argmem: readwrite, inaccessiblemem: readwrite)
declare void @free(ptr allocptr nocapture noundef) local_unnamed_addr #0

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef zeroext i1 @_Z11remove_backPP4Node(ptr noundef %0) local_unnamed_addr #1 {
  %2 = icmp eq ptr %0, null
  br i1 %2, label %14, label %3

3:                                                ; preds = %1
  %4 = load ptr, ptr %0, align 8, !tbaa !5
  %5 = icmp eq ptr %4, null
  br i1 %5, label %14, label %.preheader

.preheader:                                       ; preds = %3, %.preheader
  %.014 = phi ptr [ %7, %.preheader ], [ %4, %3 ]
  %.0 = phi ptr [ %.014, %.preheader ], [ undef, %3 ]
  %6 = getelementptr inbounds i8, ptr %.014, i64 8
  %7 = load ptr, ptr %6, align 8, !tbaa !9
  %.not = icmp eq ptr %7, %4
  br i1 %.not, label %8, label %.preheader, !llvm.loop !12

8:                                                ; preds = %.preheader
  %9 = icmp eq ptr %.014, %4
  br i1 %9, label %10, label %11

10:                                               ; preds = %8
  store ptr null, ptr %0, align 8, !tbaa !5
  br label %13

11:                                               ; preds = %8
  %12 = getelementptr inbounds i8, ptr %.0, i64 8
  store ptr %7, ptr %12, align 8, !tbaa !9
  br label %13

13:                                               ; preds = %11, %10
  tail call void @free(ptr noundef nonnull %.014) #2
  br label %14

14:                                               ; preds = %1, %3, %13
  %.015 = phi i1 [ true, %13 ], [ false, %3 ], [ false, %1 ]
  ret i1 %.015
}

attributes #0 = { mustprogress nounwind willreturn allockind("free") memory(argmem: readwrite, inaccessiblemem: readwrite) "alloc-family"="malloc" "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 #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, !6, i64 8}
!10 = !{!"_ZTS4Node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


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