; LLVM IR from HarshCasper/NeoAlgo :: C-Plus-Plus/dp/factorial_bottom_up.ll (Z9Factoriali)

; 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"

@fac = external dso_local global [100 x i32], align 16

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z9Factoriali(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 %10, label %7

7:                                                ; preds = %1
  %8 = load i32, ptr %3, align 4, !tbaa !5
  %9 = icmp eq i32 %8, 1
  br i1 %9, label %10, label %11

10:                                               ; preds = %7, %1
  store i32 1, ptr %2, align 4
  br label %36

11:                                               ; preds = %7
  store i32 1, ptr @fac, align 16, !tbaa !5
  store i32 1, ptr getelementptr inbounds ([100 x i32], ptr @fac, i64 0, i64 1), align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 2, ptr %4, align 4, !tbaa !5
  br label %12

12:                                               ; preds = %28, %11
  %13 = load i32, ptr %4, align 4, !tbaa !5
  %14 = load i32, ptr %3, align 4, !tbaa !5
  %15 = icmp sle i32 %13, %14
  br i1 %15, label %17, label %16

16:                                               ; preds = %12
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %31

17:                                               ; preds = %12
  %18 = load i32, ptr %4, align 4, !tbaa !5
  %19 = load i32, ptr %4, align 4, !tbaa !5
  %20 = sub nsw i32 %19, 1
  %21 = sext i32 %20 to i64
  %22 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %21
  %23 = load i32, ptr %22, align 4, !tbaa !5
  %24 = mul nsw i32 %18, %23
  %25 = load i32, ptr %4, align 4, !tbaa !5
  %26 = sext i32 %25 to i64
  %27 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %26
  store i32 %24, ptr %27, align 4, !tbaa !5
  br label %28

28:                                               ; preds = %17
  %29 = load i32, ptr %4, align 4, !tbaa !5
  %30 = add nsw i32 %29, 1
  store i32 %30, ptr %4, align 4, !tbaa !5
  br label %12, !llvm.loop !9

31:                                               ; preds = %16
  %32 = load i32, ptr %3, align 4, !tbaa !5
  %33 = sext i32 %32 to i64
  %34 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %33
  %35 = load i32, ptr %34, align 4, !tbaa !5
  store i32 %35, ptr %2, align 4
  br label %36

36:                                               ; preds = %31, %10
  %37 = load i32, ptr %2, align 4
  ret i32 %37
}

; 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"

@fac = external dso_local local_unnamed_addr global [100 x i32], align 16

; Function Attrs: mustprogress nofree norecurse nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: none) uwtable
define dso_local noundef i32 @_Z9Factoriali(i32 noundef %0) local_unnamed_addr #0 {
  %or.cond = icmp ult i32 %0, 2
  br i1 %or.cond, label %27, label %2

2:                                                ; preds = %1
  store i32 1, ptr @fac, align 16, !tbaa !5
  store i32 1, ptr getelementptr inbounds (i8, ptr @fac, i64 4), align 4, !tbaa !5
  %.not13 = icmp slt i32 %0, 2
  br i1 %.not13, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %2
  %3 = add nuw i32 %0, 1
  %wide.trip.count = zext i32 %3 to i64
  %4 = add nsw i64 %wide.trip.count, -2
  %5 = add nsw i64 %wide.trip.count, -3
  %xtraiter = and i64 %4, 3
  %6 = icmp ult i64 %5, 3
  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 %4, -4
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %.unr = phi i32 [ 1, %.lr.ph.preheader ], [ %25, %.lr.ph ]
  %indvars.iv.unr = phi i64 [ 2, %.lr.ph.preheader ], [ %indvars.iv.next.3, %.lr.ph ]
  %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, %.lr.ph.epil
  %7 = phi i32 [ %9, %.lr.ph.epil ], [ %.unr, %._crit_edge.loopexit.unr-lcssa ]
  %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil, %.lr.ph.epil ], [ %indvars.iv.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %8 = trunc nuw nsw i64 %indvars.iv.epil to i32
  %9 = mul nsw i32 %7, %8
  %10 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %indvars.iv.epil
  store i32 %9, ptr %10, align 4, !tbaa !5
  %indvars.iv.next.epil = add nuw nsw i64 %indvars.iv.epil, 1
  %epil.iter.next = add i64 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i64 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge, label %.lr.ph.epil, !llvm.loop !9

._crit_edge:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil, %2
  %11 = sext i32 %0 to i64
  %12 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %11
  %13 = load i32, ptr %12, align 4, !tbaa !5
  br label %27

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %14 = phi i32 [ 1, %.lr.ph.preheader.new ], [ %25, %.lr.ph ]
  %indvars.iv = phi i64 [ 2, %.lr.ph.preheader.new ], [ %indvars.iv.next.3, %.lr.ph ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.3, %.lr.ph ]
  %15 = trunc nuw nsw i64 %indvars.iv to i32
  %16 = mul nsw i32 %14, %15
  %17 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %indvars.iv
  store i32 %16, ptr %17, align 8, !tbaa !5
  %indvars.iv.next = or disjoint i64 %indvars.iv, 1
  %18 = trunc nuw nsw i64 %indvars.iv.next to i32
  %19 = mul nsw i32 %16, %18
  %20 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %indvars.iv.next
  store i32 %19, ptr %20, align 4, !tbaa !5
  %indvars.iv.next.1 = add nuw nsw i64 %indvars.iv, 2
  %21 = trunc nuw nsw i64 %indvars.iv.next.1 to i32
  %22 = mul nsw i32 %19, %21
  %23 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %indvars.iv.next.1
  store i32 %22, ptr %23, align 8, !tbaa !5
  %indvars.iv.next.2 = add nuw nsw i64 %indvars.iv, 3
  %24 = trunc nuw nsw i64 %indvars.iv.next.2 to i32
  %25 = mul nsw i32 %22, %24
  %26 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %indvars.iv.next.2
  store i32 %25, ptr %26, align 4, !tbaa !5
  %indvars.iv.next.3 = add nuw nsw i64 %indvars.iv, 4
  %niter.next.3 = add i64 %niter, 4
  %niter.ncmp.3 = icmp eq i64 %niter.next.3, %unroll_iter
  br i1 %niter.ncmp.3, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !11

27:                                               ; preds = %1, %._crit_edge
  %.011 = phi i32 [ %13, %._crit_edge ], [ 1, %1 ]
  ret i32 %.011
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: 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 = !{!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.unroll.disable"}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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