; LLVM IR from ahampriyanshu/algo-ds-101 :: Maths/Algebra/Permutation_And_Combination/permutation_combination.ll (Z9factorialx)

; 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 i64 @_Z9factorialx(i64 noundef %0) #0 {
  %2 = alloca i64, align 8
  %3 = alloca i64, align 8
  %4 = alloca i64, align 8
  store i64 %0, ptr %3, align 8, !tbaa !5
  %5 = load i64, ptr %3, align 8, !tbaa !5
  %6 = icmp eq i64 %5, 0
  br i1 %6, label %10, label %7

7:                                                ; preds = %1
  %8 = load i64, ptr %3, align 8, !tbaa !5
  %9 = icmp eq i64 %8, 1
  br i1 %9, label %10, label %12

10:                                               ; preds = %7, %1
  %11 = load i64, ptr %3, align 8, !tbaa !5
  store i64 %11, ptr %2, align 8
  br label %24

12:                                               ; preds = %7
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  store i64 1, ptr %4, align 8, !tbaa !5
  br label %13

13:                                               ; preds = %16, %12
  %14 = load i64, ptr %3, align 8, !tbaa !5
  %15 = icmp sgt i64 %14, 0
  br i1 %15, label %16, label %22

16:                                               ; preds = %13
  %17 = load i64, ptr %4, align 8, !tbaa !5
  %18 = load i64, ptr %3, align 8, !tbaa !5
  %19 = mul nsw i64 %17, %18
  store i64 %19, ptr %4, align 8, !tbaa !5
  %20 = load i64, ptr %3, align 8, !tbaa !5
  %21 = sub nsw i64 %20, 1
  store i64 %21, ptr %3, align 8, !tbaa !5
  br label %13, !llvm.loop !9

22:                                               ; preds = %13
  %23 = load i64, ptr %4, align 8, !tbaa !5
  store i64 %23, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  br label %24

24:                                               ; preds = %22, %10
  %25 = load i64, ptr %2, align 8
  ret i64 %25
}

; 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 = !{!"long long", !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 i64 @_Z9factorialx(i64 noundef %0) local_unnamed_addr #0 {
  %or.cond = icmp ult i64 %0, 2
  br i1 %or.cond, label %.loopexit, label %.preheader

.preheader:                                       ; preds = %1
  %2 = icmp sgt i64 %0, 0
  br i1 %2, label %.lr.ph.preheader, label %.loopexit

.lr.ph.preheader:                                 ; preds = %.preheader
  %xtraiter = and i64 %0, 7
  %3 = icmp ult i64 %0, 8
  br i1 %3, label %.loopexit.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i64 %0, 9223372036854775800
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %.014 = phi i64 [ 1, %.lr.ph.preheader.new ], [ %18, %.lr.ph ]
  %.01013 = phi i64 [ %0, %.lr.ph.preheader.new ], [ %19, %.lr.ph ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.7, %.lr.ph ]
  %4 = mul nuw nsw i64 %.014, %.01013
  %5 = add nsw i64 %.01013, -1
  %6 = mul nuw nsw i64 %4, %5
  %7 = add nsw i64 %.01013, -2
  %8 = mul nuw nsw i64 %6, %7
  %9 = add nsw i64 %.01013, -3
  %10 = mul nuw nsw i64 %8, %9
  %11 = add nsw i64 %.01013, -4
  %12 = mul nuw nsw i64 %10, %11
  %13 = add nsw i64 %.01013, -5
  %14 = mul nuw nsw i64 %12, %13
  %15 = add nsw i64 %.01013, -6
  %16 = mul nuw nsw i64 %14, %15
  %17 = add nsw i64 %.01013, -7
  %18 = mul nuw nsw i64 %16, %17
  %19 = add nsw i64 %.01013, -8
  %niter.next.7 = add i64 %niter, 8
  %niter.ncmp.7.not = icmp eq i64 %niter.next.7, %unroll_iter
  br i1 %niter.ncmp.7.not, label %.loopexit.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !5

.loopexit.loopexit.unr-lcssa:                     ; preds = %.lr.ph, %.lr.ph.preheader
  %.lcssa.ph = phi i64 [ poison, %.lr.ph.preheader ], [ %18, %.lr.ph ]
  %.014.unr = phi i64 [ 1, %.lr.ph.preheader ], [ %18, %.lr.ph ]
  %.01013.unr = phi i64 [ %0, %.lr.ph.preheader ], [ %19, %.lr.ph ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %.loopexit, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %.loopexit.loopexit.unr-lcssa, %.lr.ph.epil
  %.014.epil = phi i64 [ %20, %.lr.ph.epil ], [ %.014.unr, %.loopexit.loopexit.unr-lcssa ]
  %.01013.epil = phi i64 [ %21, %.lr.ph.epil ], [ %.01013.unr, %.loopexit.loopexit.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %.loopexit.loopexit.unr-lcssa ]
  %20 = mul nuw nsw i64 %.014.epil, %.01013.epil
  %21 = add nsw i64 %.01013.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 %.loopexit, label %.lr.ph.epil, !llvm.loop !7

.loopexit:                                        ; preds = %.loopexit.loopexit.unr-lcssa, %.lr.ph.epil, %.preheader, %1
  %.011 = phi i64 [ %0, %1 ], [ 1, %.preheader ], [ %.lcssa.ph, %.loopexit.loopexit.unr-lcssa ], [ %20, %.lr.ph.epil ]
  ret i64 %.011
}

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"}
!7 = distinct !{!7, !8}
!8 = !{!"llvm.loop.unroll.disable"}


; Effective O3 passes: CorrelatedValuePropagationPass,GVNPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass