; LLVM IR from AllAlgorithms/c :: algorithms/bit-manipulation (josephus)

; 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 @josephus(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %5 = load i32, ptr %3, align 4, !tbaa !5
  %6 = icmp eq i32 %5, 0
  br i1 %6, label %7, label %8

7:                                                ; preds = %1
  store i32 0, ptr %2, align 4
  br label %26

8:                                                ; preds = %1
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 -2147483648, ptr %4, align 4, !tbaa !5
  br label %9

9:                                                ; preds = %14, %8
  %10 = load i32, ptr %3, align 4, !tbaa !5
  %11 = load i32, ptr %4, align 4, !tbaa !5
  %12 = and i32 %10, %11
  %13 = icmp eq i32 %12, 0
  br i1 %13, label %14, label %17

14:                                               ; preds = %9
  %15 = load i32, ptr %4, align 4, !tbaa !5
  %16 = lshr i32 %15, 1
  store i32 %16, ptr %4, align 4, !tbaa !5
  br label %9, !llvm.loop !9

17:                                               ; preds = %9
  %18 = load i32, ptr %4, align 4, !tbaa !5
  %19 = load i32, ptr %3, align 4, !tbaa !5
  %20 = xor i32 %19, %18
  store i32 %20, ptr %3, align 4, !tbaa !5
  %21 = load i32, ptr %3, align 4, !tbaa !5
  %22 = shl i32 %21, 1
  store i32 %22, ptr %3, align 4, !tbaa !5
  %23 = load i32, ptr %3, align 4, !tbaa !5
  %24 = add i32 %23, 1
  store i32 %24, ptr %3, align 4, !tbaa !5
  %25 = load i32, ptr %3, align 4, !tbaa !5
  store i32 %25, ptr %2, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %26

26:                                               ; preds = %17, %7
  %27 = load i32, ptr %2, align 4
  ret i32 %27
}

; 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 @josephus(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp eq i32 %0, 0
  br i1 %2, label %10, label %.preheader

.preheader:                                       ; preds = %1, %.preheader
  %.0 = phi i32 [ %5, %.preheader ], [ -2147483648, %1 ]
  %3 = and i32 %.0, %0
  %4 = icmp eq i32 %3, 0
  %5 = lshr i32 %.0, 1
  br i1 %4, label %.preheader, label %6, !llvm.loop !5

6:                                                ; preds = %.preheader
  %7 = xor i32 %.0, %0
  %8 = shl i32 %7, 1
  %9 = or disjoint i32 %8, 1
  br label %10

10:                                               ; preds = %1, %6
  %.010 = phi i32 [ %9, %6 ], [ 0, %1 ]
  ret i32 %.010
}

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,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass