; LLVM IR from wuzhouhui/leetcode :: 89_gray_code (grayCode)

; 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"

@res = external hidden global ptr, align 8
@p = external hidden global i32, align 4

; Function Attrs: nounwind uwtable
define dso_local ptr @grayCode(i32 noundef %0, ptr noundef %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca ptr, align 8
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  store i32 %0, ptr %4, align 4, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !9
  %8 = load i32, ptr %4, align 4, !tbaa !5
  %9 = icmp ne i32 %8, 0
  br i1 %9, label %16, label %10

10:                                               ; preds = %2
  %11 = load ptr, ptr %5, align 8, !tbaa !9
  store i32 1, ptr %11, align 4, !tbaa !5
  %12 = call noalias ptr @malloc(i64 noundef 4) #3
  store ptr %12, ptr @res, align 8, !tbaa !9
  %13 = load ptr, ptr @res, align 8, !tbaa !9
  %14 = getelementptr inbounds i32, ptr %13, i64 0
  store i32 0, ptr %14, align 4, !tbaa !5
  %15 = load ptr, ptr @res, align 8, !tbaa !9
  store ptr %15, ptr %3, align 8
  br label %35

16:                                               ; preds = %2
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #4
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #4
  store ptr null, ptr @res, align 8, !tbaa !9
  %17 = load i32, ptr %4, align 4, !tbaa !5
  %18 = shl i32 1, %17
  store i32 %18, ptr %7, align 4, !tbaa !5
  store i32 0, ptr %6, align 4, !tbaa !5
  br label %19

19:                                               ; preds = %28, %16
  %20 = load i32, ptr %6, align 4, !tbaa !5
  %21 = load i32, ptr %7, align 4, !tbaa !5
  %22 = icmp ult i32 %20, %21
  br i1 %22, label %23, label %31

23:                                               ; preds = %19
  %24 = load i32, ptr %6, align 4, !tbaa !5
  %25 = lshr i32 %24, 1
  %26 = load i32, ptr %6, align 4, !tbaa !5
  %27 = xor i32 %25, %26
  call void @add_ans(i32 noundef %27)
  br label %28

28:                                               ; preds = %23
  %29 = load i32, ptr %6, align 4, !tbaa !5
  %30 = add i32 %29, 1
  store i32 %30, ptr %6, align 4, !tbaa !5
  br label %19, !llvm.loop !11

31:                                               ; preds = %19
  %32 = load i32, ptr @p, align 4, !tbaa !5
  %33 = load ptr, ptr %5, align 8, !tbaa !9
  store i32 %32, ptr %33, align 4, !tbaa !5
  %34 = load ptr, ptr @res, align 8, !tbaa !9
  store ptr %34, ptr %3, align 8
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #4
  br label %35

35:                                               ; preds = %31, %10
  %36 = load ptr, ptr %3, align 8
  ret ptr %36
}

; Function Attrs: nounwind allocsize(0)
declare noalias ptr @malloc(i64 noundef) #1

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

; Function Attrs: nounwind uwtable
declare hidden void @add_ans(i32 noundef) #0

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

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 = { nounwind allocsize(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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #3 = { nounwind allocsize(0) }
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/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"

@res = external hidden local_unnamed_addr global ptr, align 8
@p = external hidden local_unnamed_addr global i32, align 4

; Function Attrs: nounwind uwtable
define dso_local ptr @grayCode(i32 noundef %0, ptr nocapture noundef writeonly %1) local_unnamed_addr #0 {
  %.not = icmp eq i32 %0, 0
  br i1 %.not, label %3, label %5

3:                                                ; preds = %2
  store i32 1, ptr %1, align 4, !tbaa !5
  %4 = tail call noalias dereferenceable_or_null(4) ptr @malloc(i64 noundef 4) #2
  store ptr %4, ptr @res, align 8, !tbaa !9
  store i32 0, ptr %4, align 4, !tbaa !5
  br label %14

5:                                                ; preds = %2
  store ptr null, ptr @res, align 8, !tbaa !9
  br label %6

6:                                                ; preds = %5, %6
  %.0911 = phi i32 [ 0, %5 ], [ %9, %6 ]
  %7 = lshr i32 %.0911, 1
  %8 = xor i32 %7, %.0911
  tail call void @add_ans(i32 noundef %8)
  %9 = add i32 %.0911, 1
  %.09.highbits = lshr i32 %9, %0
  %10 = icmp eq i32 %.09.highbits, 0
  br i1 %10, label %6, label %11, !llvm.loop !11

11:                                               ; preds = %6
  %12 = load i32, ptr @p, align 4, !tbaa !5
  store i32 %12, ptr %1, align 4, !tbaa !5
  %13 = load ptr, ptr @res, align 8, !tbaa !9
  br label %14

14:                                               ; preds = %11, %3
  %.0 = phi ptr [ %13, %11 ], [ %4, %3 ]
  ret ptr %.0
}

; Function Attrs: mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite)
declare noalias noundef ptr @malloc(i64 noundef) local_unnamed_addr #1

; Function Attrs: nounwind uwtable
declare hidden void @add_ans(i32 noundef) local_unnamed_addr #0

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 = { mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite) "alloc-family"="malloc" "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 = { nounwind allocsize(0) }

!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"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,LoopRotatePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass