; LLVM IR from xxks-kkk/algo :: linkedList/josephus (nonLinkedListSol)

; 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"

; Function Attrs: nounwind uwtable
define dso_local i32 @fls(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = icmp eq i32 %6, 0
  br i1 %7, label %8, label %9

8:                                                ; preds = %1
  store i32 0, ptr %2, align 4
  store i32 1, ptr %5, align 4
  br label %21

9:                                                ; preds = %1
  store i32 1, ptr %4, align 4, !tbaa !5
  br label %10

10:                                               ; preds = %16, %9
  %11 = load i32, ptr %3, align 4, !tbaa !5
  %12 = icmp ne i32 %11, 1
  br i1 %12, label %13, label %19

13:                                               ; preds = %10
  %14 = load i32, ptr %3, align 4, !tbaa !5
  %15 = lshr i32 %14, 1
  store i32 %15, ptr %3, align 4, !tbaa !5
  br label %16

16:                                               ; preds = %13
  %17 = load i32, ptr %4, align 4, !tbaa !5
  %18 = add nsw i32 %17, 1
  store i32 %18, ptr %4, align 4, !tbaa !5
  br label %10, !llvm.loop !9

19:                                               ; preds = %10
  %20 = load i32, ptr %4, align 4, !tbaa !5
  store i32 %20, ptr %2, align 4
  store i32 1, ptr %5, align 4
  br label %21

21:                                               ; preds = %19, %8
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  %22 = load i32, ptr %2, align 4
  ret i32 %22
}

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

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

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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { 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 = 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"

; Function Attrs: nofree norecurse nosync nounwind memory(none) uwtable
define dso_local i32 @fls(i32 noundef %0) local_unnamed_addr #0 {
  %switch = icmp ult i32 %0, 2
  br i1 %switch, label %.loopexit12, label %.lr.ph

.lr.ph:                                           ; preds = %1, %.lr.ph
  %.011 = phi i32 [ %3, %.lr.ph ], [ 1, %1 ]
  %.0610 = phi i32 [ %2, %.lr.ph ], [ %0, %1 ]
  %2 = lshr i32 %.0610, 1
  %3 = add nuw nsw i32 %.011, 1
  %.not = icmp eq i32 %2, 1
  br i1 %.not, label %.loopexit12, label %.lr.ph, !llvm.loop !5

.loopexit12:                                      ; preds = %.lr.ph, %1
  %.07 = phi i32 [ %0, %1 ], [ %3, %.lr.ph ]
  ret i32 %.07
}

attributes #0 = { nofree norecurse nosync nounwind memory(none) 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 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


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