; LLVM IR from AnneLivia/Competitive-Programming :: Data Structures/Linked List/Doubly Linked List (Implemented With Struct)/doublylin_e54ec8b3 (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, 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 i32 @_Z8get_backPP4Node(ptr noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %5 = load ptr, ptr %3, align 8, !tbaa !5
  %6 = icmp eq ptr %5, null
  br i1 %6, label %11, label %7

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

11:                                               ; preds = %7, %1
  store i32 1061109567, ptr %2, align 4
  br label %28

12:                                               ; preds = %7
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %13 = load ptr, ptr %3, align 8, !tbaa !5
  %14 = load ptr, ptr %13, align 8, !tbaa !5
  store ptr %14, ptr %4, align 8, !tbaa !5
  br label %15

15:                                               ; preds = %20, %12
  %16 = load ptr, ptr %4, align 8, !tbaa !5
  %17 = getelementptr inbounds %struct.Node, ptr %16, i32 0, i32 1
  %18 = load ptr, ptr %17, align 8, !tbaa !9
  %19 = icmp ne ptr %18, null
  br i1 %19, label %20, label %24

20:                                               ; preds = %15
  %21 = load ptr, ptr %4, align 8, !tbaa !5
  %22 = getelementptr inbounds %struct.Node, ptr %21, i32 0, i32 1
  %23 = load ptr, ptr %22, align 8, !tbaa !9
  store ptr %23, ptr %4, align 8, !tbaa !5
  br label %15, !llvm.loop !12

24:                                               ; preds = %15
  %25 = load ptr, ptr %4, align 8, !tbaa !5
  %26 = getelementptr inbounds %struct.Node, ptr %25, i32 0, i32 0
  %27 = load i32, ptr %26, align 8, !tbaa !14
  store i32 %27, ptr %2, align 4
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  br label %28

28:                                               ; preds = %24, %11
  %29 = load i32, ptr %2, align 4
  ret i32 %29
}

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, !6, i64 8}
!10 = !{!"_ZTS4Node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}
!14 = !{!10, !11, i64 0}


; 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 i32 @_Z8get_backPP4Node(ptr noundef readonly %0) local_unnamed_addr #0 {
  %2 = icmp eq ptr %0, null
  br i1 %2, label %10, label %3

3:                                                ; preds = %1
  %4 = load ptr, ptr %0, align 8, !tbaa !5
  %5 = icmp eq ptr %4, null
  br i1 %5, label %10, label %.preheader

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

8:                                                ; preds = %.preheader
  %9 = load i32, ptr %.0, align 8, !tbaa !14
  br label %10

10:                                               ; preds = %1, %3, %8
  %.06 = phi i32 [ %9, %8 ], [ 1061109567, %3 ], [ 1061109567, %1 ]
  ret i32 %.06
}

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, !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, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}
!14 = !{!10, !11, i64 0}


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