; LLVM IR from div-bargali/Data-Structures-and-Algorithms :: C++/Data-Structures/LinkedList/MergeSort in Linked List.ll (Z9mergeSortP4node)

; 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: mustprogress nounwind uwtable
declare dso_local noundef ptr @_Z5splitP4node(ptr noundef) #1

; Function Attrs: mustprogress uwtable
declare dso_local noundef ptr @_Z8convergeP4nodeS0_(ptr noundef, ptr noundef) #2

; Function Attrs: mustprogress uwtable
define dso_local noundef ptr @_Z9mergeSortP4node(ptr noundef %0) #2 {
  %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 = icmp ne ptr %6, null
  br i1 %7, label %8, label %13

8:                                                ; preds = %1
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = getelementptr inbounds %struct.node, ptr %9, i32 0, i32 1
  %11 = load ptr, ptr %10, align 8, !tbaa !9
  %12 = icmp eq ptr %11, null
  br i1 %12, label %13, label %15

13:                                               ; preds = %8, %1
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %14, ptr %2, align 8
  br label %24

15:                                               ; preds = %8
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %16, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #3
  %17 = load ptr, ptr %3, align 8, !tbaa !5
  %18 = call noundef ptr @_Z5splitP4node(ptr noundef %17)
  store ptr %18, ptr %5, align 8, !tbaa !5
  %19 = load ptr, ptr %4, align 8, !tbaa !5
  %20 = call noundef ptr @_Z9mergeSortP4node(ptr noundef %19)
  %21 = load ptr, ptr %5, align 8, !tbaa !5
  %22 = call noundef ptr @_Z9mergeSortP4node(ptr noundef %21)
  %23 = call noundef ptr @_Z8convergeP4nodeS0_(ptr noundef %20, ptr noundef %22)
  store ptr %23, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  br label %24

24:                                               ; preds = %15, %13
  %25 = load ptr, ptr %2, align 8
  ret ptr %25
}

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 = { 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 #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}


; 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 uwtable
declare dso_local noundef ptr @_Z5splitP4node(ptr noundef) local_unnamed_addr #0

; Function Attrs: mustprogress uwtable
declare dso_local noundef ptr @_Z8convergeP4nodeS0_(ptr noundef, ptr noundef) local_unnamed_addr #1

; Function Attrs: mustprogress uwtable
define dso_local noundef ptr @_Z9mergeSortP4node(ptr noundef %0) local_unnamed_addr #1 {
  %.not = icmp eq ptr %0, null
  br i1 %.not, label %common.ret9, label %2

2:                                                ; preds = %1
  %3 = getelementptr inbounds i8, ptr %0, i64 8
  %4 = load ptr, ptr %3, align 8, !tbaa !5
  %5 = icmp eq ptr %4, null
  br i1 %5, label %common.ret9, label %6

common.ret9:                                      ; preds = %1, %2, %6
  %common.ret9.op = phi ptr [ %10, %6 ], [ %0, %2 ], [ null, %1 ]
  ret ptr %common.ret9.op

6:                                                ; preds = %2
  %7 = tail call noundef ptr @_Z5splitP4node(ptr noundef nonnull %0)
  %8 = tail call noundef ptr @_Z9mergeSortP4node(ptr noundef nonnull %0)
  %9 = tail call noundef ptr @_Z9mergeSortP4node(ptr noundef %7)
  %10 = tail call noundef ptr @_Z8convergeP4nodeS0_(ptr noundef %8, ptr noundef %9)
  br label %common.ret9
}

attributes #0 = { 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 #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" }

!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 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}


; Effective O3 passes: CorrelatedValuePropagationPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,SROAPass,SimplifyCFGPass,TailCallElimPass