; LLVM IR from HarshCasper/NeoAlgo :: C-Plus-Plus/dp/factorial_top_down.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 uwtable
define dso_local noundef i32 @_Z9Factoriali(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %4 = load i32, ptr %3, align 4, !tbaa !5
  %5 = icmp eq i32 %4, 0
  br i1 %5, label %6, label %7

6:                                                ; preds = %1
  store i32 1, ptr %2, align 4
  br label %31

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
  store i32 1, ptr %2, align 4
  br label %31

11:                                               ; preds = %7
  %12 = load i32, ptr %3, align 4, !tbaa !5
  %13 = sext i32 %12 to i64
  %14 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %13
  %15 = load i32, ptr %14, align 4, !tbaa !5
  %16 = icmp ne i32 %15, 0
  br i1 %16, label %17, label %22

17:                                               ; preds = %11
  %18 = load i32, ptr %3, align 4, !tbaa !5
  %19 = sext i32 %18 to i64
  %20 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %19
  %21 = load i32, ptr %20, align 4, !tbaa !5
  store i32 %21, ptr %2, align 4
  br label %31

22:                                               ; preds = %11
  %23 = load i32, ptr %3, align 4, !tbaa !5
  %24 = load i32, ptr %3, align 4, !tbaa !5
  %25 = sub nsw i32 %24, 1
  %26 = call noundef i32 @_Z9Factoriali(i32 noundef %25)
  %27 = mul nsw i32 %23, %26
  %28 = load i32, ptr %3, align 4, !tbaa !5
  %29 = sext i32 %28 to i64
  %30 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %29
  store i32 %27, ptr %30, align 4, !tbaa !5
  store i32 %27, ptr %2, align 4
  br label %31

31:                                               ; preds = %22, %17, %10, %6
  %32 = load i32, ptr %2, align 4
  ret i32 %32
}

attributes #0 = { mustprogress 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"}


; 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 nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: none) uwtable
define dso_local noundef i32 @_Z9Factoriali(i32 noundef %0) local_unnamed_addr #0 {
  %switch = icmp ult i32 %0, 2
  br i1 %switch, label %common.ret10, label %2

2:                                                ; preds = %1
  %3 = sext i32 %0 to i64
  %4 = getelementptr inbounds [100 x i32], ptr @fac, i64 0, i64 %3
  %5 = load i32, ptr %4, align 4, !tbaa !5
  %.not = icmp eq i32 %5, 0
  br i1 %.not, label %6, label %common.ret10

common.ret10:                                     ; preds = %1, %2, %6
  %common.ret10.op = phi i32 [ %9, %6 ], [ 1, %1 ], [ %5, %2 ]
  ret i32 %common.ret10.op

6:                                                ; preds = %2
  %7 = add nsw i32 %0, -1
  %8 = tail call noundef i32 @_Z9Factoriali(i32 noundef %7)
  %9 = mul nsw i32 %8, %0
  store i32 %9, ptr %4, align 4, !tbaa !5
  br label %common.ret10
}

attributes #0 = { mustprogress nofree 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"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,IPSCCPPass,InstCombinePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass