; LLVM IR from sbshah97/DS-Algo-Handbook :: Algorithms/Sort_Algorithms/Merge_Sort (merge_Sort)

; 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"

@arr = external dso_local global [100 x i32], align 16
@.str = external hidden unnamed_addr constant [43 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [3 x i8], align 1
@.str.2 = external hidden unnamed_addr constant [4 x i8], align 1

; 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
declare dso_local void @mergeSort(i32 noundef, i32 noundef) #1

; Function Attrs: nounwind uwtable
define dso_local i32 @main() #1 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #3
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #3
  %4 = call i32 (ptr, ...) @printf(ptr noundef @.str)
  %5 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str.1, ptr noundef %3)
  store i32 0, ptr %2, align 4, !tbaa !5
  br label %6

6:                                                ; preds = %15, %0
  %7 = load i32, ptr %2, align 4, !tbaa !5
  %8 = load i32, ptr %3, align 4, !tbaa !5
  %9 = icmp slt i32 %7, %8
  br i1 %9, label %10, label %18

10:                                               ; preds = %6
  %11 = load i32, ptr %2, align 4, !tbaa !5
  %12 = sext i32 %11 to i64
  %13 = getelementptr inbounds [100 x i32], ptr @arr, i64 0, i64 %12
  %14 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str.1, ptr noundef %13)
  br label %15

15:                                               ; preds = %10
  %16 = load i32, ptr %2, align 4, !tbaa !5
  %17 = add nsw i32 %16, 1
  store i32 %17, ptr %2, align 4, !tbaa !5
  br label %6, !llvm.loop !9

18:                                               ; preds = %6
  %19 = load i32, ptr %3, align 4, !tbaa !5
  %20 = sub nsw i32 %19, 1
  call void @mergeSort(i32 noundef 0, i32 noundef %20)
  store i32 0, ptr %2, align 4, !tbaa !5
  br label %21

21:                                               ; preds = %31, %18
  %22 = load i32, ptr %2, align 4, !tbaa !5
  %23 = load i32, ptr %3, align 4, !tbaa !5
  %24 = icmp slt i32 %22, %23
  br i1 %24, label %25, label %34

25:                                               ; preds = %21
  %26 = load i32, ptr %2, align 4, !tbaa !5
  %27 = sext i32 %26 to i64
  %28 = getelementptr inbounds [100 x i32], ptr @arr, i64 0, i64 %27
  %29 = load i32, ptr %28, align 4, !tbaa !5
  %30 = call i32 (ptr, ...) @printf(ptr noundef @.str.2, i32 noundef %29)
  br label %31

31:                                               ; preds = %25
  %32 = load i32, ptr %2, align 4, !tbaa !5
  %33 = add nsw i32 %32, 1
  store i32 %33, ptr %2, align 4, !tbaa !5
  br label %21, !llvm.loop !11

34:                                               ; preds = %21
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #3
  ret i32 0
}

declare i32 @printf(ptr noundef, ...) #2

declare i32 @__isoc99_scanf(ptr noundef, ...) #2

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 = { "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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}
!11 = distinct !{!11, !10}


; 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"

@arr = external dso_local global [100 x i32], align 16
@.str = external hidden unnamed_addr constant [43 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [3 x i8], align 1
@.str.2 = external hidden unnamed_addr constant [4 x i8], align 1

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind uwtable
declare dso_local void @mergeSort(i32 noundef, i32 noundef) local_unnamed_addr #1

; Function Attrs: nounwind uwtable
define dso_local noundef i32 @main() local_unnamed_addr #1 {
  %1 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %1) #3
  %2 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str)
  %3 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str.1, ptr noundef nonnull %1)
  %4 = load i32, ptr %1, align 4, !tbaa !5
  %5 = icmp sgt i32 %4, 0
  br i1 %5, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %0, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ]
  %6 = getelementptr inbounds [100 x i32], ptr @arr, i64 0, i64 %indvars.iv
  %7 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str.1, ptr noundef nonnull %6)
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %8 = load i32, ptr %1, align 4, !tbaa !5
  %9 = sext i32 %8 to i64
  %10 = icmp slt i64 %indvars.iv.next, %9
  br i1 %10, label %.lr.ph, label %._crit_edge, !llvm.loop !9

._crit_edge:                                      ; preds = %.lr.ph, %0
  %.lcssa = phi i32 [ %4, %0 ], [ %8, %.lr.ph ]
  %11 = add nsw i32 %.lcssa, -1
  call void @mergeSort(i32 noundef 0, i32 noundef %11)
  %12 = load i32, ptr %1, align 4, !tbaa !5
  %13 = icmp sgt i32 %12, 0
  br i1 %13, label %.lr.ph10, label %._crit_edge11

.lr.ph10:                                         ; preds = %._crit_edge, %.lr.ph10
  %indvars.iv14 = phi i64 [ %indvars.iv.next15, %.lr.ph10 ], [ 0, %._crit_edge ]
  %14 = getelementptr inbounds [100 x i32], ptr @arr, i64 0, i64 %indvars.iv14
  %15 = load i32, ptr %14, align 4, !tbaa !5
  %16 = call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.2, i32 noundef %15)
  %indvars.iv.next15 = add nuw nsw i64 %indvars.iv14, 1
  %17 = load i32, ptr %1, align 4, !tbaa !5
  %18 = sext i32 %17 to i64
  %19 = icmp slt i64 %indvars.iv.next15, %18
  br i1 %19, label %.lr.ph10, label %._crit_edge11, !llvm.loop !11

._crit_edge11:                                    ; preds = %.lr.ph10, %._crit_edge
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %1) #3
  ret i32 0
}

; Function Attrs: nofree nounwind
declare noundef i32 @printf(ptr nocapture noundef readonly, ...) local_unnamed_addr #2

; Function Attrs: nofree nounwind
declare noundef i32 @__isoc99_scanf(ptr nocapture noundef readonly, ...) local_unnamed_addr #2

attributes #0 = { mustprogress 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 = { nofree nounwind "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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}
!11 = distinct !{!11, !10}


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