; LLVM IR from tangjz/acm-icpc :: usaco/Training/Chapter 2 Bigger challenges/hamming.ll (Z3dfsii)

; 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"

@n = external dso_local global i32, align 4
@maxval = external dso_local global i32, align 4
@ans = external dso_local global [64 x i32], align 16

; 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: mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_Z7compareii(i32 noundef, i32 noundef) #1

; Function Attrs: mustprogress uwtable
define dso_local void @_Z3dfsii(i32 noundef %0, i32 noundef %1) #2 {
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !5
  %7 = load i32, ptr %3, align 4, !tbaa !5
  %8 = load i32, ptr @n, align 4, !tbaa !5
  %9 = icmp eq i32 %7, %8
  br i1 %9, label %10, label %11

10:                                               ; preds = %2
  br label %37

11:                                               ; preds = %2
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  %12 = load i32, ptr %4, align 4, !tbaa !5
  %13 = add nsw i32 %12, 1
  store i32 %13, ptr %5, align 4, !tbaa !5
  br label %14

14:                                               ; preds = %32, %11
  %15 = load i32, ptr %5, align 4, !tbaa !5
  %16 = load i32, ptr @maxval, align 4, !tbaa !5
  %17 = icmp slt i32 %15, %16
  br i1 %17, label %19, label %18

18:                                               ; preds = %14
  store i32 2, ptr %6, align 4
  br label %35

19:                                               ; preds = %14
  %20 = load i32, ptr %5, align 4, !tbaa !5
  %21 = load i32, ptr %3, align 4, !tbaa !5
  %22 = call noundef zeroext i1 @_Z7compareii(i32 noundef %20, i32 noundef %21)
  br i1 %22, label %23, label %31

23:                                               ; preds = %19
  %24 = load i32, ptr %5, align 4, !tbaa !5
  %25 = load i32, ptr %3, align 4, !tbaa !5
  %26 = sext i32 %25 to i64
  %27 = getelementptr inbounds [64 x i32], ptr @ans, i64 0, i64 %26
  store i32 %24, ptr %27, align 4, !tbaa !5
  %28 = load i32, ptr %3, align 4, !tbaa !5
  %29 = add nsw i32 %28, 1
  %30 = load i32, ptr %5, align 4, !tbaa !5
  call void @_Z3dfsii(i32 noundef %29, i32 noundef %30)
  store i32 1, ptr %6, align 4
  br label %35

31:                                               ; preds = %19
  br label %32

32:                                               ; preds = %31
  %33 = load i32, ptr %5, align 4, !tbaa !5
  %34 = add nsw i32 %33, 1
  store i32 %34, ptr %5, align 4, !tbaa !5
  br label %14, !llvm.loop !9

35:                                               ; preds = %23, %18
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  %36 = load i32, ptr %6, align 4
  switch i32 %36, label %38 [
    i32 2, label %37
    i32 1, label %37
  ]

37:                                               ; preds = %35, %35, %10
  ret void

38:                                               ; preds = %35
  unreachable
}

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

@n = external dso_local local_unnamed_addr global i32, align 4
@maxval = external dso_local local_unnamed_addr global i32, align 4
@ans = external dso_local local_unnamed_addr global [64 x i32], align 16

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_Z7compareii(i32 noundef, i32 noundef) local_unnamed_addr #0

; Function Attrs: mustprogress nounwind uwtable
define dso_local void @_Z3dfsii(i32 noundef %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = load i32, ptr @n, align 4, !tbaa !5
  %4 = icmp eq i32 %3, %0
  br i1 %4, label %.loopexit, label %.preheader.preheader

.preheader.preheader:                             ; preds = %2
  %5 = sext i32 %0 to i64
  br label %.preheader

.preheader:                                       ; preds = %.preheader.preheader, %tailrecurse
  %indvars.iv = phi i64 [ %5, %.preheader.preheader ], [ %indvars.iv.next, %tailrecurse ]
  %.tr1115 = phi i32 [ %1, %.preheader.preheader ], [ %.0, %tailrecurse ]
  %6 = trunc nsw i64 %indvars.iv to i32
  br label %7

7:                                                ; preds = %.preheader, %10
  %.0.in = phi i32 [ %.0, %10 ], [ %.tr1115, %.preheader ]
  %.0 = add nsw i32 %.0.in, 1
  %8 = load i32, ptr @maxval, align 4, !tbaa !5
  %9 = icmp slt i32 %.0, %8
  br i1 %9, label %10, label %.loopexit

10:                                               ; preds = %7
  %11 = tail call noundef zeroext i1 @_Z7compareii(i32 noundef %.0, i32 noundef %6)
  br i1 %11, label %tailrecurse, label %7, !llvm.loop !9

tailrecurse:                                      ; preds = %10
  %12 = getelementptr inbounds [64 x i32], ptr @ans, i64 0, i64 %indvars.iv
  store i32 %.0, ptr %12, align 4, !tbaa !5
  %indvars.iv.next = add nsw i64 %indvars.iv, 1
  %13 = load i32, ptr @n, align 4, !tbaa !5
  %14 = trunc nsw i64 %indvars.iv.next to i32
  %15 = icmp eq i32 %13, %14
  br i1 %15, label %.loopexit, label %.preheader

.loopexit:                                        ; preds = %tailrecurse, %7, %2
  ret void
}

attributes #0 = { mustprogress 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" }

!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: GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass