; LLVM IR from sbshah97/DS-Algo-Handbook :: labs/lab2/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"

@A = external dso_local global [100000 x i32], align 16
@.str = external hidden unnamed_addr constant [3 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [4 x i8], align 1
@.str.2 = external hidden unnamed_addr constant [2 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
  %4 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #3
  %5 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str, ptr noundef %2)
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #3
  store i32 0, ptr %3, align 4, !tbaa !5
  br label %6

6:                                                ; preds = %16, %0
  %7 = load i32, ptr %3, align 4, !tbaa !5
  %8 = load i32, ptr %2, align 4, !tbaa !5
  %9 = icmp slt i32 %7, %8
  br i1 %9, label %11, label %10

10:                                               ; preds = %6
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  br label %19

11:                                               ; preds = %6
  %12 = load i32, ptr %3, align 4, !tbaa !5
  %13 = sext i32 %12 to i64
  %14 = getelementptr inbounds [100000 x i32], ptr @A, i64 0, i64 %13
  %15 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str, ptr noundef %14)
  br label %16

16:                                               ; preds = %11
  %17 = load i32, ptr %3, align 4, !tbaa !5
  %18 = add nsw i32 %17, 1
  store i32 %18, ptr %3, align 4, !tbaa !5
  br label %6, !llvm.loop !9

19:                                               ; preds = %10
  %20 = load i32, ptr %2, align 4, !tbaa !5
  %21 = sub nsw i32 %20, 1
  call void @mergeSort(i32 noundef 0, i32 noundef %21)
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #3
  store i32 0, ptr %4, align 4, !tbaa !5
  br label %22

22:                                               ; preds = %33, %19
  %23 = load i32, ptr %4, align 4, !tbaa !5
  %24 = load i32, ptr %2, align 4, !tbaa !5
  %25 = icmp slt i32 %23, %24
  br i1 %25, label %27, label %26

26:                                               ; preds = %22
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #3
  br label %36

27:                                               ; preds = %22
  %28 = load i32, ptr %4, align 4, !tbaa !5
  %29 = sext i32 %28 to i64
  %30 = getelementptr inbounds [100000 x i32], ptr @A, i64 0, i64 %29
  %31 = load i32, ptr %30, align 4, !tbaa !5
  %32 = call i32 (ptr, ...) @printf(ptr noundef @.str.1, i32 noundef %31)
  br label %33

33:                                               ; preds = %27
  %34 = load i32, ptr %4, align 4, !tbaa !5
  %35 = add nsw i32 %34, 1
  store i32 %35, ptr %4, align 4, !tbaa !5
  br label %22, !llvm.loop !11

36:                                               ; preds = %26
  %37 = call i32 (ptr, ...) @printf(ptr noundef @.str.2)
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #3
  ret i32 0
}

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

declare i32 @printf(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"

@A = external dso_local global [100000 x i32], align 16
@.str = external hidden unnamed_addr constant [3 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [4 x i8], align 1
@.str.2 = external hidden unnamed_addr constant [2 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 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str, ptr noundef nonnull %1)
  %3 = load i32, ptr %1, align 4, !tbaa !5
  %4 = icmp sgt i32 %3, 0
  br i1 %4, label %.lr.ph, label %._crit_edge

._crit_edge:                                      ; preds = %.lr.ph, %0
  %.lcssa = phi i32 [ %3, %0 ], [ %10, %.lr.ph ]
  %5 = add nsw i32 %.lcssa, -1
  call void @mergeSort(i32 noundef 0, i32 noundef %5)
  %6 = load i32, ptr %1, align 4, !tbaa !5
  %7 = icmp sgt i32 %6, 0
  br i1 %7, label %.lr.ph11, label %._crit_edge12

.lr.ph:                                           ; preds = %0, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ]
  %8 = getelementptr inbounds [100000 x i32], ptr @A, i64 0, i64 %indvars.iv
  %9 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str, ptr noundef nonnull %8)
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %10 = load i32, ptr %1, align 4, !tbaa !5
  %11 = sext i32 %10 to i64
  %12 = icmp slt i64 %indvars.iv.next, %11
  br i1 %12, label %.lr.ph, label %._crit_edge, !llvm.loop !9

._crit_edge12:                                    ; preds = %.lr.ph11, %._crit_edge
  %13 = call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.2)
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %1) #3
  ret i32 0

.lr.ph11:                                         ; preds = %._crit_edge, %.lr.ph11
  %indvars.iv15 = phi i64 [ %indvars.iv.next16, %.lr.ph11 ], [ 0, %._crit_edge ]
  %14 = getelementptr inbounds [100000 x i32], ptr @A, i64 0, i64 %indvars.iv15
  %15 = load i32, ptr %14, align 4, !tbaa !5
  %16 = call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.1, i32 noundef %15)
  %indvars.iv.next16 = add nuw nsw i64 %indvars.iv15, 1
  %17 = load i32, ptr %1, align 4, !tbaa !5
  %18 = sext i32 %17 to i64
  %19 = icmp slt i64 %indvars.iv.next16, %18
  br i1 %19, label %.lr.ph11, label %._crit_edge12, !llvm.loop !11
}

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

; Function Attrs: nofree nounwind
declare noundef i32 @printf(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