; LLVM IR from ahampriyanshu/algo-ds-101 :: Algorithms/Sorting/Merge_Sort/Application of Merge Sort (Count_Inversions)

; 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"

; Function Attrs: nounwind uwtable
declare dso_local i64 @merge(ptr noundef, i64 noundef, i64 noundef, i64 noundef) #0

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: nounwind uwtable
define dso_local i64 @merge_sort(ptr noundef %0, i64 noundef %1, i64 noundef %2) #0 {
  %4 = alloca i64, align 8
  %5 = alloca ptr, align 8
  %6 = alloca i64, align 8
  %7 = alloca i64, align 8
  %8 = alloca i64, align 8
  %9 = alloca i64, align 8
  %10 = alloca i64, align 8
  %11 = alloca i64, align 8
  %12 = alloca i64, align 8
  store ptr %0, ptr %5, align 8, !tbaa !5
  store i64 %1, ptr %6, align 8, !tbaa !9
  store i64 %2, ptr %7, align 8, !tbaa !9
  %13 = load i64, ptr %6, align 8, !tbaa !9
  %14 = load i64, ptr %7, align 8, !tbaa !9
  %15 = icmp slt i64 %13, %14
  br i1 %15, label %16, label %42

16:                                               ; preds = %3
  call void @llvm.lifetime.start.p0(i64 8, ptr %8) #2
  %17 = load i64, ptr %6, align 8, !tbaa !9
  %18 = load i64, ptr %7, align 8, !tbaa !9
  %19 = add nsw i64 %17, %18
  %20 = sdiv i64 %19, 2
  store i64 %20, ptr %8, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %9) #2
  %21 = load ptr, ptr %5, align 8, !tbaa !5
  %22 = load i64, ptr %6, align 8, !tbaa !9
  %23 = load i64, ptr %8, align 8, !tbaa !9
  %24 = call i64 @merge_sort(ptr noundef %21, i64 noundef %22, i64 noundef %23)
  store i64 %24, ptr %9, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %10) #2
  %25 = load ptr, ptr %5, align 8, !tbaa !5
  %26 = load i64, ptr %8, align 8, !tbaa !9
  %27 = add nsw i64 %26, 1
  %28 = load i64, ptr %7, align 8, !tbaa !9
  %29 = call i64 @merge_sort(ptr noundef %25, i64 noundef %27, i64 noundef %28)
  store i64 %29, ptr %10, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %11) #2
  %30 = load ptr, ptr %5, align 8, !tbaa !5
  %31 = load i64, ptr %6, align 8, !tbaa !9
  %32 = load i64, ptr %8, align 8, !tbaa !9
  %33 = add nsw i64 %32, 1
  %34 = load i64, ptr %7, align 8, !tbaa !9
  %35 = call i64 @merge(ptr noundef %30, i64 noundef %31, i64 noundef %33, i64 noundef %34)
  store i64 %35, ptr %11, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %12) #2
  %36 = load i64, ptr %9, align 8, !tbaa !9
  %37 = load i64, ptr %10, align 8, !tbaa !9
  %38 = add nsw i64 %36, %37
  %39 = load i64, ptr %11, align 8, !tbaa !9
  %40 = add nsw i64 %38, %39
  store i64 %40, ptr %12, align 8, !tbaa !9
  %41 = load i64, ptr %12, align 8, !tbaa !9
  store i64 %41, ptr %4, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %12) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %11) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %10) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %9) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %8) #2
  br label %43

42:                                               ; preds = %3
  store i64 0, ptr %4, align 8
  br label %43

43:                                               ; preds = %42, %16
  %44 = load i64, ptr %4, align 8
  ret i64 %44
}

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" }
attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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, !10, i64 0}
!10 = !{!"long long", !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: nounwind uwtable
declare dso_local i64 @merge(ptr noundef, i64 noundef, i64 noundef, i64 noundef) local_unnamed_addr #0

; Function Attrs: nounwind uwtable
define dso_local i64 @merge_sort(ptr noundef %0, i64 noundef %1, i64 noundef %2) local_unnamed_addr #0 {
  %4 = icmp slt i64 %1, %2
  br i1 %4, label %5, label %common.ret20

common.ret20:                                     ; preds = %3, %5
  %common.ret20.op = phi i64 [ %13, %5 ], [ 0, %3 ]
  ret i64 %common.ret20.op

5:                                                ; preds = %3
  %6 = add nsw i64 %2, %1
  %7 = sdiv i64 %6, 2
  %8 = tail call i64 @merge_sort(ptr noundef %0, i64 noundef %1, i64 noundef %7)
  %9 = add nsw i64 %7, 1
  %10 = tail call i64 @merge_sort(ptr noundef %0, i64 noundef %9, i64 noundef %2)
  %11 = tail call i64 @merge(ptr noundef %0, i64 noundef %1, i64 noundef %9, i64 noundef %2)
  %12 = add nsw i64 %10, %8
  %13 = add nsw i64 %12, %11
  br label %common.ret20
}

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)"}


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