; LLVM IR from IsaacAsante/HackerRank :: Problem Solving/Data Structures/Arrays/Arrays - DS (arrays)

; 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
define dso_local ptr @reverseArray(i32 noundef %0, ptr noundef %1, ptr noundef %2) #0 {
  %4 = alloca i32, align 4
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  %9 = alloca i32, align 4
  store i32 %0, ptr %4, align 4, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !9
  store ptr %2, ptr %6, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #2
  %10 = load i32, ptr %4, align 4, !tbaa !5
  %11 = sdiv i32 %10, 2
  store i32 %11, ptr %7, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #2
  %12 = load i32, ptr %4, align 4, !tbaa !5
  %13 = sub nsw i32 %12, 1
  store i32 %13, ptr %8, align 4, !tbaa !5
  br label %14

14:                                               ; preds = %45, %3
  %15 = load i32, ptr %8, align 4, !tbaa !5
  %16 = load i32, ptr %7, align 4, !tbaa !5
  %17 = icmp sge i32 %15, %16
  br i1 %17, label %19, label %18

18:                                               ; preds = %14
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #2
  br label %48

19:                                               ; preds = %14
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #2
  %20 = load ptr, ptr %5, align 8, !tbaa !9
  %21 = load i32, ptr %8, align 4, !tbaa !5
  %22 = sext i32 %21 to i64
  %23 = getelementptr inbounds i32, ptr %20, i64 %22
  %24 = load i32, ptr %23, align 4, !tbaa !5
  store i32 %24, ptr %9, align 4, !tbaa !5
  %25 = load ptr, ptr %5, align 8, !tbaa !9
  %26 = load i32, ptr %4, align 4, !tbaa !5
  %27 = load i32, ptr %8, align 4, !tbaa !5
  %28 = sub nsw i32 %26, %27
  %29 = sub nsw i32 %28, 1
  %30 = sext i32 %29 to i64
  %31 = getelementptr inbounds i32, ptr %25, i64 %30
  %32 = load i32, ptr %31, align 4, !tbaa !5
  %33 = load ptr, ptr %5, align 8, !tbaa !9
  %34 = load i32, ptr %8, align 4, !tbaa !5
  %35 = sext i32 %34 to i64
  %36 = getelementptr inbounds i32, ptr %33, i64 %35
  store i32 %32, ptr %36, align 4, !tbaa !5
  %37 = load i32, ptr %9, align 4, !tbaa !5
  %38 = load ptr, ptr %5, align 8, !tbaa !9
  %39 = load i32, ptr %4, align 4, !tbaa !5
  %40 = load i32, ptr %8, align 4, !tbaa !5
  %41 = sub nsw i32 %39, %40
  %42 = sub nsw i32 %41, 1
  %43 = sext i32 %42 to i64
  %44 = getelementptr inbounds i32, ptr %38, i64 %43
  store i32 %37, ptr %44, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #2
  br label %45

45:                                               ; preds = %19
  %46 = load i32, ptr %8, align 4, !tbaa !5
  %47 = add nsw i32 %46, -1
  store i32 %47, ptr %8, align 4, !tbaa !5
  br label %14, !llvm.loop !11

48:                                               ; preds = %18
  %49 = load i32, ptr %4, align 4, !tbaa !5
  %50 = load ptr, ptr %6, align 8, !tbaa !9
  store i32 %49, ptr %50, align 4, !tbaa !5
  %51 = load ptr, ptr %5, align 8, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #2
  ret ptr %51
}

; 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

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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"any pointer", !7, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


; 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 norecurse nosync nounwind memory(argmem: readwrite) uwtable
define dso_local noundef ptr @reverseArray(i32 noundef %0, ptr noundef returned %1, ptr nocapture noundef writeonly %2) local_unnamed_addr #0 {
  %.not.not18 = icmp sgt i32 %0, 0
  br i1 %.not.not18, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %3
  %4 = lshr i32 %0, 1
  %5 = zext nneg i32 %0 to i64
  %6 = zext nneg i32 %4 to i64
  br label %.lr.ph

._crit_edge:                                      ; preds = %.lr.ph, %3
  store i32 %0, ptr %2, align 4, !tbaa !5
  ret ptr %1

.lr.ph:                                           ; preds = %.lr.ph.preheader, %.lr.ph
  %indvars.iv = phi i64 [ %5, %.lr.ph.preheader ], [ %indvars.iv.next, %.lr.ph ]
  %indvars.iv.next = add nsw i64 %indvars.iv, -1
  %7 = getelementptr inbounds i32, ptr %1, i64 %indvars.iv.next
  %8 = load i32, ptr %7, align 4, !tbaa !5
  %9 = trunc nsw i64 %indvars.iv to i32
  %10 = sub i32 %0, %9
  %11 = sext i32 %10 to i64
  %12 = getelementptr inbounds i32, ptr %1, i64 %11
  %13 = load i32, ptr %12, align 4, !tbaa !5
  store i32 %13, ptr %7, align 4, !tbaa !5
  store i32 %8, ptr %12, align 4, !tbaa !5
  %.not.not = icmp sgt i64 %indvars.iv.next, %6
  br i1 %.not.not, label %.lr.ph, label %._crit_edge, !llvm.loop !9
}

attributes #0 = { nofree norecurse nosync nounwind memory(argmem: readwrite) 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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}


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