; LLVM IR from upupming/algorithm :: acwing/算法基础课/第四讲 数学知识/博弈论/892. 台阶-Nim游戏 (main)

; 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 }

@n = external dso_local global i32, align 4
@a = external dso_local global i32, align 4
@_ZSt3cin = external global %"class.std::basic_istream", align 8
@.str = external hidden unnamed_addr constant [4 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [3 x i8], align 1

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

5:                                                ; preds = %20, %0
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = load i32, ptr @n, align 4, !tbaa !5
  %8 = icmp sle i32 %6, %7
  br i1 %8, label %10, label %9

9:                                                ; preds = %5
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  br label %23

10:                                               ; preds = %5
  %11 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) @a)
  %12 = load i32, ptr %3, align 4, !tbaa !5
  %13 = srem i32 %12, 2
  %14 = icmp ne i32 %13, 0
  br i1 %14, label %15, label %19

15:                                               ; preds = %10
  %16 = load i32, ptr @a, align 4, !tbaa !5
  %17 = load i32, ptr %2, align 4, !tbaa !5
  %18 = xor i32 %17, %16
  store i32 %18, ptr %2, align 4, !tbaa !5
  br label %19

19:                                               ; preds = %15, %10
  br label %20

20:                                               ; preds = %19
  %21 = load i32, ptr %3, align 4, !tbaa !5
  %22 = add nsw i32 %21, 1
  store i32 %22, ptr %3, align 4, !tbaa !5
  br label %5, !llvm.loop !9

23:                                               ; preds = %9
  %24 = load i32, ptr %2, align 4, !tbaa !5
  %25 = icmp ne i32 %24, 0
  br i1 %25, label %26, label %28

26:                                               ; preds = %23
  %27 = call i32 @puts(ptr noundef @.str)
  br label %30

28:                                               ; preds = %23
  %29 = call i32 @puts(ptr noundef @.str.1)
  br label %30

30:                                               ; preds = %28, %26
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #3
  ret i32 0
}

declare noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16), ptr noundef nonnull align 4 dereferenceable(4)) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #2

declare i32 @puts(ptr noundef) #1

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 = { "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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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"

%"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 }

@n = external dso_local global i32, align 4
@a = external dso_local global i32, align 4
@_ZSt3cin = external global %"class.std::basic_istream", align 8
@.str = external hidden unnamed_addr constant [4 x i8], align 1
@.str.1 = external hidden unnamed_addr constant [3 x i8], align 1

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() local_unnamed_addr #0 {
  %1 = tail call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) @n)
  %2 = load i32, ptr @n, align 4, !tbaa !5
  %.not8 = icmp slt i32 %2, 1
  br i1 %.not8, label %._crit_edge.thread, label %.lr.ph

._crit_edge:                                      ; preds = %.lr.ph
  %3 = icmp eq i32 %7, %.059
  br i1 %3, label %._crit_edge.thread, label %10

.lr.ph:                                           ; preds = %0, %.lr.ph
  %.010 = phi i32 [ %8, %.lr.ph ], [ 1, %0 ]
  %.059 = phi i32 [ %.1, %.lr.ph ], [ 0, %0 ]
  %4 = tail call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) @a)
  %5 = and i32 %.010, 1
  %.not7 = icmp eq i32 %5, 0
  %6 = load i32, ptr @a, align 4
  %7 = select i1 %.not7, i32 0, i32 %6
  %.1 = xor i32 %7, %.059
  %8 = add nuw nsw i32 %.010, 1
  %9 = load i32, ptr @n, align 4, !tbaa !5
  %.not.not = icmp slt i32 %.010, %9
  br i1 %.not.not, label %.lr.ph, label %._crit_edge, !llvm.loop !9

._crit_edge.thread:                               ; preds = %0, %._crit_edge
  br label %10

10:                                               ; preds = %._crit_edge, %._crit_edge.thread
  %.str.1.sink = phi ptr [ @.str.1, %._crit_edge.thread ], [ @.str, %._crit_edge ]
  %11 = tail call i32 @puts(ptr noundef nonnull dereferenceable(1) %.str.1.sink)
  ret i32 0
}

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 #1

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

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 = { "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" }

!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,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass