; LLVM IR from codemistic/Data-Structures-and-Algorithms :: CPP/questions/perfectnumber.ll (Z13perfectnumberi)

; 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: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z13perfectnumberi(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  store i32 0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 1, ptr %4, align 4, !tbaa !5
  br label %5

5:                                                ; preds = %20, %1
  %6 = load i32, ptr %4, align 4, !tbaa !5
  %7 = load i32, ptr %2, align 4, !tbaa !5
  %8 = icmp slt i32 %6, %7
  br i1 %8, label %10, label %9

9:                                                ; preds = %5
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %23

10:                                               ; preds = %5
  %11 = load i32, ptr %2, align 4, !tbaa !5
  %12 = load i32, ptr %4, align 4, !tbaa !5
  %13 = srem i32 %11, %12
  %14 = icmp eq i32 %13, 0
  br i1 %14, label %15, label %19

15:                                               ; preds = %10
  %16 = load i32, ptr %4, align 4, !tbaa !5
  %17 = load i32, ptr %3, align 4, !tbaa !5
  %18 = add nsw i32 %17, %16
  store i32 %18, ptr %3, align 4, !tbaa !5
  br label %19

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

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

23:                                               ; preds = %9
  %24 = load i32, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  ret i32 %24
}

; 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 = { 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 #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++ 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: mustprogress nofree norecurse nosync nounwind willreturn memory(none) uwtable
define dso_local noundef i32 @_Z13perfectnumberi(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp sgt i32 %0, 1
  br i1 %2, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %1
  %3 = add nsw i32 %0, -1
  %xtraiter = and i32 %3, 1
  %4 = icmp eq i32 %0, 2
  br i1 %4, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i32 %3, -2
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %spec.select.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %spec.select.1, %.lr.ph ]
  %.011.unr = phi i32 [ 1, %.lr.ph.preheader ], [ %15, %.lr.ph ]
  %.0810.unr = phi i32 [ 0, %.lr.ph.preheader ], [ %spec.select.1, %.lr.ph ]
  %lcmp.mod.not = icmp eq i32 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa
  %5 = urem i32 %0, %.011.unr
  %6 = icmp eq i32 %5, 0
  %7 = select i1 %6, i32 %.011.unr, i32 0
  %spec.select.epil = add nuw nsw i32 %7, %.0810.unr
  br label %._crit_edge

._crit_edge:                                      ; preds = %.lr.ph.epil, %._crit_edge.loopexit.unr-lcssa, %1
  %.08.lcssa = phi i32 [ 0, %1 ], [ %spec.select.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %spec.select.epil, %.lr.ph.epil ]
  ret i32 %.08.lcssa

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %.011 = phi i32 [ 1, %.lr.ph.preheader.new ], [ %15, %.lr.ph ]
  %.0810 = phi i32 [ 0, %.lr.ph.preheader.new ], [ %spec.select.1, %.lr.ph ]
  %niter = phi i32 [ 0, %.lr.ph.preheader.new ], [ %niter.next.1, %.lr.ph ]
  %8 = urem i32 %0, %.011
  %9 = icmp eq i32 %8, 0
  %10 = select i1 %9, i32 %.011, i32 0
  %spec.select = add nuw nsw i32 %10, %.0810
  %11 = add nuw nsw i32 %.011, 1
  %12 = urem i32 %0, %11
  %13 = icmp eq i32 %12, 0
  %14 = select i1 %13, i32 %11, i32 0
  %spec.select.1 = add nuw nsw i32 %14, %spec.select
  %15 = add nuw nsw i32 %.011, 2
  %niter.next.1 = add i32 %niter, 2
  %niter.ncmp.1 = icmp eq i32 %niter.next.1, %unroll_iter
  br i1 %niter.ncmp.1, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !5
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn 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,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass