; LLVM IR from vladpolisuk/algorithms :: Combinatorics/Permutations/code.ll (Z16change_directionPiS_ii)

; 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: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: mustprogress nounwind uwtable
define dso_local void @_Z16change_directionPiS_ii(ptr noundef %0, ptr noundef %1, i32 noundef %2, i32 noundef %3) #1 {
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  %9 = alloca i32, align 4
  store ptr %0, ptr %5, align 8, !tbaa !5
  store ptr %1, ptr %6, align 8, !tbaa !5
  store i32 %2, ptr %7, align 4, !tbaa !9
  store i32 %3, ptr %8, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #2
  store i32 0, ptr %9, align 4, !tbaa !9
  br label %10

10:                                               ; preds = %31, %4
  %11 = load i32, ptr %9, align 4, !tbaa !9
  %12 = load i32, ptr %8, align 4, !tbaa !9
  %13 = icmp slt i32 %11, %12
  br i1 %13, label %15, label %14

14:                                               ; preds = %10
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #2
  br label %34

15:                                               ; preds = %10
  %16 = load ptr, ptr %5, align 8, !tbaa !5
  %17 = load i32, ptr %9, align 4, !tbaa !9
  %18 = sext i32 %17 to i64
  %19 = getelementptr inbounds i32, ptr %16, i64 %18
  %20 = load i32, ptr %19, align 4, !tbaa !9
  %21 = load i32, ptr %7, align 4, !tbaa !9
  %22 = icmp sgt i32 %20, %21
  br i1 %22, label %23, label %30

23:                                               ; preds = %15
  %24 = load ptr, ptr %6, align 8, !tbaa !5
  %25 = load i32, ptr %9, align 4, !tbaa !9
  %26 = sext i32 %25 to i64
  %27 = getelementptr inbounds i32, ptr %24, i64 %26
  %28 = load i32, ptr %27, align 4, !tbaa !9
  %29 = mul nsw i32 %28, -1
  store i32 %29, ptr %27, align 4, !tbaa !9
  br label %30

30:                                               ; preds = %23, %15
  br label %31

31:                                               ; preds = %30
  %32 = load i32, ptr %9, align 4, !tbaa !9
  %33 = add nsw i32 %32, 1
  store i32 %33, ptr %9, align 4, !tbaa !9
  br label %10, !llvm.loop !11

34:                                               ; preds = %14
  ret void
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !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"

; Function Attrs: mustprogress nofree norecurse nosync nounwind memory(argmem: readwrite) uwtable
define dso_local void @_Z16change_directionPiS_ii(ptr nocapture noundef readonly %0, ptr nocapture noundef %1, i32 noundef %2, i32 noundef %3) local_unnamed_addr #0 {
  %5 = icmp sgt i32 %3, 0
  br i1 %5, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %4
  %wide.trip.count = zext nneg i32 %3 to i64
  %xtraiter = and i64 %wide.trip.count, 1
  %6 = icmp eq i32 %3, 1
  br i1 %6, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i64 %wide.trip.count, 2147483646
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %28, %.lr.ph.preheader
  %indvars.iv.unr = phi i64 [ 0, %.lr.ph.preheader ], [ %indvars.iv.next.1, %28 ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa
  %7 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.unr
  %8 = load i32, ptr %7, align 4, !tbaa !5
  %9 = icmp sgt i32 %8, %2
  br i1 %9, label %10, label %._crit_edge

10:                                               ; preds = %.lr.ph.epil
  %11 = getelementptr inbounds i32, ptr %1, i64 %indvars.iv.unr
  %12 = load i32, ptr %11, align 4, !tbaa !5
  %13 = sub nsw i32 0, %12
  store i32 %13, ptr %11, align 4, !tbaa !5
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %10, %.lr.ph.epil, %4
  ret void

.lr.ph:                                           ; preds = %28, %.lr.ph.preheader.new
  %indvars.iv = phi i64 [ 0, %.lr.ph.preheader.new ], [ %indvars.iv.next.1, %28 ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.1, %28 ]
  %14 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv
  %15 = load i32, ptr %14, align 4, !tbaa !5
  %16 = icmp sgt i32 %15, %2
  br i1 %16, label %17, label %.lr.ph.1

17:                                               ; preds = %.lr.ph
  %18 = getelementptr inbounds i32, ptr %1, i64 %indvars.iv
  %19 = load i32, ptr %18, align 4, !tbaa !5
  %20 = sub nsw i32 0, %19
  store i32 %20, ptr %18, align 4, !tbaa !5
  br label %.lr.ph.1

.lr.ph.1:                                         ; preds = %.lr.ph, %17
  %indvars.iv.next = or disjoint i64 %indvars.iv, 1
  %21 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next
  %22 = load i32, ptr %21, align 4, !tbaa !5
  %23 = icmp sgt i32 %22, %2
  br i1 %23, label %24, label %28

24:                                               ; preds = %.lr.ph.1
  %25 = getelementptr inbounds i32, ptr %1, i64 %indvars.iv.next
  %26 = load i32, ptr %25, align 4, !tbaa !5
  %27 = sub nsw i32 0, %26
  store i32 %27, ptr %25, align 4, !tbaa !5
  br label %28

28:                                               ; preds = %24, %.lr.ph.1
  %indvars.iv.next.1 = add nuw nsw i64 %indvars.iv, 2
  %niter.next.1 = add i64 %niter, 2
  %niter.ncmp.1 = icmp eq i64 %niter.next.1, %unroll_iter
  br i1 %niter.ncmp.1, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !9
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind memory(argmem: readwrite) 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 = !{!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: EarlyCSEPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass