; LLVM IR from Lakhankumawat/LearnCPP :: S-SortingAlgorithms (MergeSort)

; 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"

%"class.std::basic_istream" = type { ptr, i64, %"class.std::basic_ios" }
%"class.std::basic_ios" = type { %"class.std::ios_base", ptr, i8, i8, ptr, ptr, ptr, ptr }
%"class.std::ios_base" = type { ptr, i64, i64, i32, i32, i32, ptr, %"struct.std::ios_base::_Words", [8 x %"struct.std::ios_base::_Words"], i32, ptr, %"class.std::locale" }
%"struct.std::ios_base::_Words" = type { ptr, i64 }
%"class.std::locale" = type { ptr }

@_ZSt3cin = external global %"class.std::basic_istream", align 8

; 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
declare ptr @llvm.stacksave.p0() #1

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

; Function Attrs: nocallback nofree nosync nounwind willreturn
declare void @llvm.stackrestore.p0(ptr) #1

; Function Attrs: mustprogress uwtable
declare dso_local void @_Z10Merge_sortPiii(ptr noundef, i32 noundef, i32 noundef) #2

; Function Attrs: mustprogress uwtable
declare dso_local void @_Z5PrintPii(ptr noundef, i32 noundef) #2

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() #3 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  %5 = alloca i64, align 8
  %6 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #5
  %7 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %2)
  %8 = load i32, ptr %2, align 4, !tbaa !5
  %9 = zext i32 %8 to i64
  %10 = call ptr @llvm.stacksave.p0()
  store ptr %10, ptr %4, align 8
  %11 = alloca i32, i64 %9, align 16
  store i64 %9, ptr %5, align 8
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #5
  store i32 0, ptr %6, align 4, !tbaa !5
  br label %12

12:                                               ; preds = %22, %0
  %13 = load i32, ptr %6, align 4, !tbaa !5
  %14 = load i32, ptr %2, align 4, !tbaa !5
  %15 = icmp slt i32 %13, %14
  br i1 %15, label %17, label %16

16:                                               ; preds = %12
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #5
  br label %25

17:                                               ; preds = %12
  %18 = load i32, ptr %6, align 4, !tbaa !5
  %19 = sext i32 %18 to i64
  %20 = getelementptr inbounds i32, ptr %11, i64 %19
  %21 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %20)
  br label %22

22:                                               ; preds = %17
  %23 = load i32, ptr %6, align 4, !tbaa !5
  %24 = add nsw i32 %23, 1
  store i32 %24, ptr %6, align 4, !tbaa !5
  br label %12, !llvm.loop !9

25:                                               ; preds = %16
  %26 = load i32, ptr %2, align 4, !tbaa !5
  %27 = sub nsw i32 %26, 1
  call void @_Z10Merge_sortPiii(ptr noundef %11, i32 noundef 0, i32 noundef %27)
  %28 = load i32, ptr %2, align 4, !tbaa !5
  call void @_Z5PrintPii(ptr noundef %11, i32 noundef %28)
  store i32 0, ptr %1, align 4
  %29 = load ptr, ptr %4, align 8
  call void @llvm.stackrestore.p0(ptr %29)
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #5
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #5
  %30 = load i32, ptr %1, align 4
  ret i32 %30
}

declare noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16), ptr noundef nonnull align 4 dereferenceable(4)) #4

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { nocallback nofree nosync nounwind willreturn }
attributes #2 = { mustprogress 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 #3 = { mustprogress norecurse 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 #4 = { "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 #5 = { 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++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"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"

%"class.std::basic_istream" = type { ptr, i64, %"class.std::basic_ios" }
%"class.std::basic_ios" = type { %"class.std::ios_base", ptr, i8, i8, ptr, ptr, ptr, ptr }
%"class.std::ios_base" = type { ptr, i64, i64, i32, i32, i32, ptr, %"struct.std::ios_base::_Words", [8 x %"struct.std::ios_base::_Words"], i32, ptr, %"class.std::locale" }
%"struct.std::ios_base::_Words" = type { ptr, i64 }
%"class.std::locale" = type { ptr }

@_ZSt3cin = external global %"class.std::basic_istream", align 8

; 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
declare ptr @llvm.stacksave.p0() #1

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

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn
declare void @llvm.stackrestore.p0(ptr) #1

; Function Attrs: mustprogress uwtable
declare dso_local void @_Z10Merge_sortPiii(ptr noundef, i32 noundef, i32 noundef) local_unnamed_addr #2

; Function Attrs: mustprogress uwtable
declare dso_local void @_Z5PrintPii(ptr noundef, i32 noundef) local_unnamed_addr #2

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() local_unnamed_addr #3 {
  %1 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %1) #5
  %2 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %1)
  %3 = load i32, ptr %1, align 4, !tbaa !5
  %4 = zext i32 %3 to i64
  %5 = call ptr @llvm.stacksave.p0()
  %6 = alloca i32, i64 %4, align 16
  %7 = load i32, ptr %1, align 4, !tbaa !5
  %8 = icmp sgt i32 %7, 0
  br i1 %8, label %.lr.ph, label %._crit_edge

._crit_edge:                                      ; preds = %.lr.ph, %0
  %.lcssa = phi i32 [ %7, %0 ], [ %13, %.lr.ph ]
  %9 = add nsw i32 %.lcssa, -1
  call void @_Z10Merge_sortPiii(ptr noundef nonnull %6, i32 noundef 0, i32 noundef %9)
  %10 = load i32, ptr %1, align 4, !tbaa !5
  call void @_Z5PrintPii(ptr noundef nonnull %6, i32 noundef %10)
  call void @llvm.stackrestore.p0(ptr %5)
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %1) #5
  ret i32 0

.lr.ph:                                           ; preds = %0, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ]
  %11 = getelementptr inbounds i32, ptr %6, i64 %indvars.iv
  %12 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %11)
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %13 = load i32, ptr %1, align 4, !tbaa !5
  %14 = sext i32 %13 to i64
  %15 = icmp slt i64 %indvars.iv.next, %14
  br i1 %15, label %.lr.ph, label %._crit_edge, !llvm.loop !9
}

declare noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16), ptr noundef nonnull align 4 dereferenceable(4)) local_unnamed_addr #4

attributes #0 = { mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress nocallback nofree nosync nounwind willreturn }
attributes #2 = { mustprogress 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 #3 = { mustprogress norecurse 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 #4 = { "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 #5 = { 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++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}


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