; LLVM IR from kaynewbie/algorithm :: algorithm/CodingInterviews (binary-linked-list)

; 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.BinaryListNode = 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: nounwind uwtable
define dso_local void @reverseBinaryLinkedList(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  %5 = load ptr, ptr %2, align 8, !tbaa !5
  %6 = icmp eq ptr %5, null
  br i1 %6, label %7, label %8

7:                                                ; preds = %1
  br label %33

8:                                                ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #2
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %9 = load ptr, ptr %2, align 8, !tbaa !5
  %10 = load ptr, ptr %9, align 8, !tbaa !5
  store ptr %10, ptr %3, align 8, !tbaa !5
  store ptr null, ptr %4, align 8, !tbaa !5
  br label %11

11:                                               ; preds = %14, %8
  %12 = load ptr, ptr %3, align 8, !tbaa !5
  %13 = icmp ne ptr %12, null
  br i1 %13, label %14, label %30

14:                                               ; preds = %11
  %15 = load ptr, ptr %3, align 8, !tbaa !5
  %16 = getelementptr inbounds %struct.BinaryListNode, ptr %15, i32 0, i32 2
  %17 = load ptr, ptr %16, align 8, !tbaa !9
  store ptr %17, ptr %4, align 8, !tbaa !5
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  %19 = getelementptr inbounds %struct.BinaryListNode, ptr %18, i32 0, i32 1
  %20 = load ptr, ptr %19, align 8, !tbaa !12
  %21 = load ptr, ptr %3, align 8, !tbaa !5
  %22 = getelementptr inbounds %struct.BinaryListNode, ptr %21, i32 0, i32 2
  store ptr %20, ptr %22, align 8, !tbaa !9
  %23 = load ptr, ptr %4, align 8, !tbaa !5
  %24 = load ptr, ptr %3, align 8, !tbaa !5
  %25 = getelementptr inbounds %struct.BinaryListNode, ptr %24, i32 0, i32 1
  store ptr %23, ptr %25, align 8, !tbaa !12
  %26 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %26, ptr %4, align 8, !tbaa !5
  %27 = load ptr, ptr %3, align 8, !tbaa !5
  %28 = getelementptr inbounds %struct.BinaryListNode, ptr %27, i32 0, i32 1
  %29 = load ptr, ptr %28, align 8, !tbaa !12
  store ptr %29, ptr %3, align 8, !tbaa !5
  br label %11, !llvm.loop !13

30:                                               ; preds = %11
  %31 = load ptr, ptr %4, align 8, !tbaa !5
  %32 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %31, ptr %32, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #2
  br label %33

33:                                               ; preds = %30, %7
  ret void
}

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, !6, i64 16}
!10 = !{!"BinaryListNode", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !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: nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local void @reverseBinaryLinkedList(ptr noundef %0) local_unnamed_addr #0 {
  %2 = icmp eq ptr %0, null
  br i1 %2, label %9, label %3

3:                                                ; preds = %1
  %4 = load ptr, ptr %0, align 8, !tbaa !5
  %.not14 = icmp eq ptr %4, null
  br i1 %.not14, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %3, %.lr.ph
  %.01215 = phi ptr [ %6, %.lr.ph ], [ %4, %3 ]
  %5 = getelementptr inbounds i8, ptr %.01215, i64 16
  %6 = load ptr, ptr %5, align 8, !tbaa !9
  %7 = getelementptr inbounds i8, ptr %.01215, i64 8
  %8 = load ptr, ptr %7, align 8, !tbaa !12
  store ptr %8, ptr %5, align 8, !tbaa !9
  store ptr %6, ptr %7, align 8, !tbaa !12
  %.not = icmp eq ptr %6, null
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !13

._crit_edge:                                      ; preds = %.lr.ph, %3
  %.0.lcssa = phi ptr [ null, %3 ], [ %.01215, %.lr.ph ]
  store ptr %.0.lcssa, ptr %0, align 8, !tbaa !5
  br label %9

9:                                                ; preds = %1, %._crit_edge
  ret void
}

attributes #0 = { 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, !6, i64 0}
!6 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !6, i64 16}
!10 = !{!"BinaryListNode", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 8}
!13 = distinct !{!13, !14}
!14 = !{!"llvm.loop.mustprogress"}


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