; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 04. Arrays (Maximum subarray sum)

; 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 }
%"class.std::basic_ostream" = type { ptr, %"class.std::basic_ios" }

@_ZSt3cin = external global %"class.std::basic_istream", align 8
@_ZSt4cout = external global %"class.std::basic_ostream", align 8

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() #0 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  %4 = alloca i64, align 8
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #4
  %9 = 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)
  %10 = load i32, ptr %2, align 4, !tbaa !5
  %11 = zext i32 %10 to i64
  %12 = call ptr @llvm.stacksave.p0()
  store ptr %12, ptr %3, align 8
  %13 = alloca i32, i64 %11, align 16
  store i64 %11, ptr %4, align 8
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #4
  store i32 0, ptr %5, align 4, !tbaa !5
  br label %14

14:                                               ; preds = %24, %0
  %15 = load i32, ptr %5, align 4, !tbaa !5
  %16 = load i32, ptr %2, align 4, !tbaa !5
  %17 = icmp slt i32 %15, %16
  br i1 %17, label %19, label %18

18:                                               ; preds = %14
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #4
  br label %27

19:                                               ; preds = %14
  %20 = load i32, ptr %5, align 4, !tbaa !5
  %21 = sext i32 %20 to i64
  %22 = getelementptr inbounds i32, ptr %13, i64 %21
  %23 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %22)
  br label %24

24:                                               ; preds = %19
  %25 = load i32, ptr %5, align 4, !tbaa !5
  %26 = add nsw i32 %25, 1
  store i32 %26, ptr %5, align 4, !tbaa !5
  br label %14, !llvm.loop !9

27:                                               ; preds = %18
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #4
  store i32 -2147483648, ptr %6, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #4
  store i32 0, ptr %7, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #4
  store i32 0, ptr %8, align 4, !tbaa !5
  br label %28

28:                                               ; preds = %50, %27
  %29 = load i32, ptr %8, align 4, !tbaa !5
  %30 = load i32, ptr %2, align 4, !tbaa !5
  %31 = icmp slt i32 %29, %30
  br i1 %31, label %33, label %32

32:                                               ; preds = %28
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #4
  br label %53

33:                                               ; preds = %28
  %34 = load i32, ptr %8, align 4, !tbaa !5
  %35 = sext i32 %34 to i64
  %36 = getelementptr inbounds i32, ptr %13, i64 %35
  %37 = load i32, ptr %36, align 4, !tbaa !5
  %38 = load i32, ptr %7, align 4, !tbaa !5
  %39 = add nsw i32 %38, %37
  store i32 %39, ptr %7, align 4, !tbaa !5
  %40 = load i32, ptr %7, align 4, !tbaa !5
  %41 = load i32, ptr %6, align 4, !tbaa !5
  %42 = icmp sgt i32 %40, %41
  br i1 %42, label %43, label %45

43:                                               ; preds = %33
  %44 = load i32, ptr %7, align 4, !tbaa !5
  store i32 %44, ptr %6, align 4, !tbaa !5
  br label %45

45:                                               ; preds = %43, %33
  %46 = load i32, ptr %7, align 4, !tbaa !5
  %47 = icmp sle i32 %46, 0
  br i1 %47, label %48, label %49

48:                                               ; preds = %45
  store i32 0, ptr %7, align 4, !tbaa !5
  br label %49

49:                                               ; preds = %48, %45
  br label %50

50:                                               ; preds = %49
  %51 = load i32, ptr %8, align 4, !tbaa !5
  %52 = add nsw i32 %51, 1
  store i32 %52, ptr %8, align 4, !tbaa !5
  br label %28, !llvm.loop !11

53:                                               ; preds = %32
  %54 = load i32, ptr %6, align 4, !tbaa !5
  %55 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, i32 noundef %54)
  store i32 0, ptr %1, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #4
  %56 = load ptr, ptr %3, align 8
  call void @llvm.stackrestore.p0(ptr %56)
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #4
  %57 = load i32, ptr %1, align 4
  ret i32 %57
}

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

declare noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16), ptr noundef nonnull align 4 dereferenceable(4)) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn
declare ptr @llvm.stacksave.p0() #3

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

declare noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8), i32 noundef) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn
declare void @llvm.stackrestore.p0(ptr) #3

attributes #0 = { 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 #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 = { nocallback nofree nosync nounwind willreturn }
attributes #4 = { 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"}
!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"

%"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 }
%"class.std::basic_ostream" = type { ptr, %"class.std::basic_ios" }

@_ZSt3cin = external global %"class.std::basic_istream", align 8
@_ZSt4cout = external global %"class.std::basic_ostream", align 8

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() local_unnamed_addr #0 {
  %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

.preheader:                                       ; preds = %.lr.ph
  %9 = icmp sgt i32 %13, 0
  br i1 %9, label %.lr.ph21.preheader, label %._crit_edge

.lr.ph21.preheader:                               ; preds = %.preheader
  %wide.trip.count = zext nneg i32 %13 to i64
  %xtraiter = and i64 %wide.trip.count, 1
  %10 = icmp eq i32 %13, 1
  br i1 %10, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph21.preheader.new

.lr.ph21.preheader.new:                           ; preds = %.lr.ph21.preheader
  %unroll_iter = and i64 %wide.trip.count, 2147483646
  br label %.lr.ph21

.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 %.preheader, !llvm.loop !9

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph21, %.lr.ph21.preheader
  %spec.select.lcssa.ph = phi i32 [ poison, %.lr.ph21.preheader ], [ %spec.select.1, %.lr.ph21 ]
  %indvars.iv25.unr = phi i64 [ 0, %.lr.ph21.preheader ], [ %indvars.iv.next26.1, %.lr.ph21 ]
  %.01319.unr = phi i32 [ 0, %.lr.ph21.preheader ], [ %spec.store.select.1, %.lr.ph21 ]
  %.01418.unr = phi i32 [ -2147483648, %.lr.ph21.preheader ], [ %spec.select.1, %.lr.ph21 ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph21.epil

.lr.ph21.epil:                                    ; preds = %._crit_edge.loopexit.unr-lcssa
  %16 = getelementptr inbounds i32, ptr %6, i64 %indvars.iv25.unr
  %17 = load i32, ptr %16, align 4, !tbaa !5
  %18 = add nsw i32 %17, %.01319.unr
  %spec.select.epil = call i32 @llvm.smax.i32(i32 %18, i32 %.01418.unr)
  br label %._crit_edge

._crit_edge:                                      ; preds = %.lr.ph21.epil, %._crit_edge.loopexit.unr-lcssa, %0, %.preheader
  %.014.lcssa = phi i32 [ -2147483648, %.preheader ], [ -2147483648, %0 ], [ %spec.select.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %spec.select.epil, %.lr.ph21.epil ]
  %19 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, i32 noundef %.014.lcssa)
  call void @llvm.stackrestore.p0(ptr %5)
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %1) #5
  ret i32 0

.lr.ph21:                                         ; preds = %.lr.ph21, %.lr.ph21.preheader.new
  %indvars.iv25 = phi i64 [ 0, %.lr.ph21.preheader.new ], [ %indvars.iv.next26.1, %.lr.ph21 ]
  %.01319 = phi i32 [ 0, %.lr.ph21.preheader.new ], [ %spec.store.select.1, %.lr.ph21 ]
  %.01418 = phi i32 [ -2147483648, %.lr.ph21.preheader.new ], [ %spec.select.1, %.lr.ph21 ]
  %niter = phi i64 [ 0, %.lr.ph21.preheader.new ], [ %niter.next.1, %.lr.ph21 ]
  %20 = getelementptr inbounds i32, ptr %6, i64 %indvars.iv25
  %21 = load i32, ptr %20, align 8, !tbaa !5
  %22 = add nsw i32 %21, %.01319
  %spec.select = call i32 @llvm.smax.i32(i32 %22, i32 %.01418)
  %spec.store.select = call i32 @llvm.smax.i32(i32 %22, i32 0)
  %indvars.iv.next26 = or disjoint i64 %indvars.iv25, 1
  %23 = getelementptr inbounds i32, ptr %6, i64 %indvars.iv.next26
  %24 = load i32, ptr %23, align 4, !tbaa !5
  %25 = add nsw i32 %24, %spec.store.select
  %spec.select.1 = call i32 @llvm.smax.i32(i32 %25, i32 %spec.select)
  %spec.store.select.1 = call i32 @llvm.smax.i32(i32 %25, i32 0)
  %indvars.iv.next26.1 = add nuw nsw i64 %indvars.iv25, 2
  %niter.next.1 = add i64 %niter, 2
  %niter.ncmp.1 = icmp eq i64 %niter.next.1, %unroll_iter
  br i1 %niter.ncmp.1, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph21, !llvm.loop !11
}

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

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 #2

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn
declare ptr @llvm.stacksave.p0() #3

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

declare noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8), i32 noundef) local_unnamed_addr #2

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn
declare void @llvm.stackrestore.p0(ptr) #3

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i32 @llvm.smax.i32(i32, i32) #4

attributes #0 = { 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 #1 = { mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 = { mustprogress nocallback nofree nosync nounwind willreturn }
attributes #4 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
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"}
!11 = distinct !{!11, !10}


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