; LLVM IR from ahampriyanshu/algo-ds-101 :: Algorithms/Sorting/Merge_Sort_on_Doubly_Linked_List (Mergesort_doubly)

; 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: nounwind uwtable
define dso_local ptr @merge(ptr noundef %0, ptr noundef %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  store ptr %0, ptr %4, align 8, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !5
  %6 = load ptr, ptr %4, align 8, !tbaa !5
  %7 = icmp ne ptr %6, null
  br i1 %7, label %10, label %8

8:                                                ; preds = %2
  %9 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %9, ptr %3, align 8
  br label %55

10:                                               ; preds = %2
  %11 = load ptr, ptr %5, align 8, !tbaa !5
  %12 = icmp ne ptr %11, null
  br i1 %12, label %15, label %13

13:                                               ; preds = %10
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %14, ptr %3, align 8
  br label %55

15:                                               ; preds = %10
  %16 = load ptr, ptr %4, align 8, !tbaa !5
  %17 = getelementptr inbounds %struct.Node, ptr %16, i32 0, i32 0
  %18 = load i32, ptr %17, align 8, !tbaa !9
  %19 = load ptr, ptr %5, align 8, !tbaa !5
  %20 = getelementptr inbounds %struct.Node, ptr %19, i32 0, i32 0
  %21 = load i32, ptr %20, align 8, !tbaa !9
  %22 = icmp slt i32 %18, %21
  br i1 %22, label %23, label %39

23:                                               ; preds = %15
  %24 = load ptr, ptr %4, align 8, !tbaa !5
  %25 = getelementptr inbounds %struct.Node, ptr %24, i32 0, i32 1
  %26 = load ptr, ptr %25, align 8, !tbaa !12
  %27 = load ptr, ptr %5, align 8, !tbaa !5
  %28 = call ptr @merge(ptr noundef %26, ptr noundef %27)
  %29 = load ptr, ptr %4, align 8, !tbaa !5
  %30 = getelementptr inbounds %struct.Node, ptr %29, i32 0, i32 1
  store ptr %28, ptr %30, align 8, !tbaa !12
  %31 = load ptr, ptr %4, align 8, !tbaa !5
  %32 = load ptr, ptr %4, align 8, !tbaa !5
  %33 = getelementptr inbounds %struct.Node, ptr %32, i32 0, i32 1
  %34 = load ptr, ptr %33, align 8, !tbaa !12
  %35 = getelementptr inbounds %struct.Node, ptr %34, i32 0, i32 2
  store ptr %31, ptr %35, align 8, !tbaa !13
  %36 = load ptr, ptr %4, align 8, !tbaa !5
  %37 = getelementptr inbounds %struct.Node, ptr %36, i32 0, i32 2
  store ptr null, ptr %37, align 8, !tbaa !13
  %38 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %38, ptr %3, align 8
  br label %55

39:                                               ; preds = %15
  %40 = load ptr, ptr %4, align 8, !tbaa !5
  %41 = load ptr, ptr %5, align 8, !tbaa !5
  %42 = getelementptr inbounds %struct.Node, ptr %41, i32 0, i32 1
  %43 = load ptr, ptr %42, align 8, !tbaa !12
  %44 = call ptr @merge(ptr noundef %40, ptr noundef %43)
  %45 = load ptr, ptr %5, align 8, !tbaa !5
  %46 = getelementptr inbounds %struct.Node, ptr %45, i32 0, i32 1
  store ptr %44, ptr %46, align 8, !tbaa !12
  %47 = load ptr, ptr %5, align 8, !tbaa !5
  %48 = load ptr, ptr %5, align 8, !tbaa !5
  %49 = getelementptr inbounds %struct.Node, ptr %48, i32 0, i32 1
  %50 = load ptr, ptr %49, align 8, !tbaa !12
  %51 = getelementptr inbounds %struct.Node, ptr %50, i32 0, i32 2
  store ptr %47, ptr %51, align 8, !tbaa !13
  %52 = load ptr, ptr %5, align 8, !tbaa !5
  %53 = getelementptr inbounds %struct.Node, ptr %52, i32 0, i32 2
  store ptr null, ptr %53, align 8, !tbaa !13
  %54 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %54, ptr %3, align 8
  br label %55

55:                                               ; preds = %39, %23, %13, %8
  %56 = load ptr, ptr %3, align 8
  ret ptr %56
}

attributes #0 = { 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" }

!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, !11, i64 0}
!10 = !{!"Node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 8}
!13 = !{!10, !6, i64 16}


; 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 nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local noundef ptr @merge(ptr noundef %0, ptr noundef %1) local_unnamed_addr #0 {
  %.not = icmp eq ptr %0, null
  br i1 %.not, label %common.ret, label %3

3:                                                ; preds = %2
  %.not23 = icmp eq ptr %1, null
  br i1 %.not23, label %common.ret, label %4

4:                                                ; preds = %3
  %5 = load i32, ptr %0, align 8, !tbaa !5
  %6 = load i32, ptr %1, align 8, !tbaa !5
  %7 = icmp slt i32 %5, %6
  br i1 %7, label %10, label %14

common.ret.sink.split:                            ; preds = %10, %14
  %.sink26 = phi ptr [ %17, %14 ], [ %13, %10 ]
  %.sink = phi ptr [ %1, %14 ], [ %0, %10 ]
  %8 = getelementptr inbounds i8, ptr %.sink26, i64 16
  store ptr %.sink, ptr %8, align 8, !tbaa !11
  %9 = getelementptr inbounds i8, ptr %.sink, i64 16
  store ptr null, ptr %9, align 8, !tbaa !11
  br label %common.ret

common.ret:                                       ; preds = %common.ret.sink.split, %2, %3
  %common.ret.op = phi ptr [ %1, %2 ], [ %0, %3 ], [ %.sink, %common.ret.sink.split ]
  ret ptr %common.ret.op

10:                                               ; preds = %4
  %11 = getelementptr inbounds i8, ptr %0, i64 8
  %12 = load ptr, ptr %11, align 8, !tbaa !12
  %13 = tail call ptr @merge(ptr noundef %12, ptr noundef nonnull %1)
  store ptr %13, ptr %11, align 8, !tbaa !12
  br label %common.ret.sink.split

14:                                               ; preds = %4
  %15 = getelementptr inbounds i8, ptr %1, i64 8
  %16 = load ptr, ptr %15, align 8, !tbaa !12
  %17 = tail call ptr @merge(ptr noundef nonnull %0, ptr noundef %16)
  store ptr %17, ptr %15, align 8, !tbaa !12
  br label %common.ret.sink.split
}

attributes #0 = { 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, !7, i64 0}
!6 = !{!"Node", !7, i64 0, !10, i64 8, !10, i64 16}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}
!11 = !{!6, !10, i64 16}
!12 = !{!6, !10, i64 8}


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