; LLVM IR from codemistic/Data-Structures-and-Algorithms :: CPP/LINKED LIST/DOUBLY LINKED LIST/microsoftquestion.ll (Z17reverselinkedlistRP4node)

; 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"

%class.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: mustprogress uwtable
define dso_local noundef ptr @_Z17reverselinkedlistRP4node(ptr noundef nonnull align 8 dereferenceable(8) %0) #1 {
  %2 = alloca ptr, align 8
  %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 = load ptr, ptr %6, align 8, !tbaa !5
  %8 = getelementptr inbounds %class.node, ptr %7, i32 0, i32 1
  %9 = load ptr, ptr %8, align 8, !tbaa !9
  %10 = icmp eq ptr %9, null
  br i1 %10, label %15, label %11

11:                                               ; preds = %1
  %12 = load ptr, ptr %3, align 8, !tbaa !5
  %13 = load ptr, ptr %12, align 8, !tbaa !5
  %14 = icmp eq ptr %13, null
  br i1 %14, label %15, label %18

15:                                               ; preds = %11, %1
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  %17 = load ptr, ptr %16, align 8, !tbaa !5
  store ptr %17, ptr %2, align 8
  br label %33

18:                                               ; preds = %11
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %19 = load ptr, ptr %3, align 8, !tbaa !5
  %20 = load ptr, ptr %19, align 8, !tbaa !5
  store ptr %20, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %21 = load ptr, ptr %3, align 8, !tbaa !5
  %22 = load ptr, ptr %21, align 8, !tbaa !5
  %23 = getelementptr inbounds %class.node, ptr %22, i32 0, i32 1
  %24 = call noundef ptr @_Z17reverselinkedlistRP4node(ptr noundef nonnull align 8 dereferenceable(8) %23)
  store ptr %24, ptr %5, align 8, !tbaa !5
  %25 = load ptr, ptr %4, align 8, !tbaa !5
  %26 = load ptr, ptr %4, align 8, !tbaa !5
  %27 = getelementptr inbounds %class.node, ptr %26, i32 0, i32 1
  %28 = load ptr, ptr %27, align 8, !tbaa !9
  %29 = getelementptr inbounds %class.node, ptr %28, i32 0, i32 1
  store ptr %25, ptr %29, align 8, !tbaa !9
  %30 = load ptr, ptr %4, align 8, !tbaa !5
  %31 = getelementptr inbounds %class.node, ptr %30, i32 0, i32 1
  store ptr null, ptr %31, align 8, !tbaa !9
  %32 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %32, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  br label %33

33:                                               ; preds = %18, %15
  %34 = load ptr, ptr %2, align 8
  ret ptr %34
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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}


; 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 nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local noundef ptr @_Z17reverselinkedlistRP4node(ptr nocapture noundef nonnull readonly align 8 dereferenceable(8) %0) local_unnamed_addr #0 {
  %2 = load ptr, ptr %0, align 8, !tbaa !5
  %3 = getelementptr inbounds i8, ptr %2, i64 8
  %4 = load ptr, ptr %3, align 8, !tbaa !9
  %5 = icmp eq ptr %4, null
  %6 = icmp eq ptr %2, null
  %or.cond = or i1 %6, %5
  br i1 %or.cond, label %common.ret11, label %7

common.ret11:                                     ; preds = %1, %7
  %common.ret11.op = phi ptr [ %8, %7 ], [ %2, %1 ]
  ret ptr %common.ret11.op

7:                                                ; preds = %1
  %8 = tail call noundef ptr @_Z17reverselinkedlistRP4node(ptr noundef nonnull align 8 dereferenceable(8) %3)
  %9 = load ptr, ptr %3, align 8, !tbaa !9
  %10 = getelementptr inbounds i8, ptr %9, i64 8
  store ptr %2, ptr %10, align 8, !tbaa !9
  store ptr null, ptr %3, align 8, !tbaa !9
  br label %common.ret11
}

attributes #0 = { mustprogress nofree 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++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS4node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass