; LLVM IR from HarshCasper/NeoAlgo :: C-Plus-Plus/other/Fast_fibonacci_last_digit.ll (Z24get_fibonacci_last_digitx)

; 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 @_Z24get_fibonacci_last_digitx(i64 noundef %0) #0 {
  %2 = alloca i64, align 8
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  store i64 %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  store i32 0, ptr %3, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 1, ptr %4, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #2
  store i32 2, ptr %6, align 4, !tbaa !9
  br label %7

7:                                                ; preds = %20, %1
  %8 = load i32, ptr %6, align 4, !tbaa !9
  %9 = sext i32 %8 to i64
  %10 = load i64, ptr %2, align 8, !tbaa !5
  %11 = icmp sle i64 %9, %10
  br i1 %11, label %13, label %12

12:                                               ; preds = %7
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #2
  br label %23

13:                                               ; preds = %7
  %14 = load i32, ptr %3, align 4, !tbaa !9
  %15 = load i32, ptr %4, align 4, !tbaa !9
  %16 = add nsw i32 %14, %15
  %17 = srem i32 %16, 10
  store i32 %17, ptr %5, align 4, !tbaa !9
  %18 = load i32, ptr %4, align 4, !tbaa !9
  store i32 %18, ptr %3, align 4, !tbaa !9
  %19 = load i32, ptr %5, align 4, !tbaa !9
  store i32 %19, ptr %4, align 4, !tbaa !9
  br label %20

20:                                               ; preds = %13
  %21 = load i32, ptr %6, align 4, !tbaa !9
  %22 = add nsw i32 %21, 1
  store i32 %22, ptr %6, align 4, !tbaa !9
  br label %7, !llvm.loop !11

23:                                               ; preds = %12
  %24 = load i32, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  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 = !{!"long long", !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 willreturn memory(none) uwtable
define dso_local noundef i32 @_Z24get_fibonacci_last_digitx(i64 noundef %0) local_unnamed_addr #0 {
  %.not11 = icmp sgt i64 %0, 1
  tail call void @llvm.assume(i1 %.not11)
  %2 = add nsw i64 %0, -1
  %3 = add nsw i64 %0, -2
  %xtraiter = and i64 %2, 3
  %4 = icmp ult i64 %3, 3
  br i1 %4, label %._crit_edge.unr-lcssa, label %.new

.new:                                             ; preds = %1
  %unroll_iter = and i64 %2, -4
  br label %.lr.ph

._crit_edge.unr-lcssa:                            ; preds = %.lr.ph, %1
  %.lcssa.ph = phi i32 [ poison, %1 ], [ %14, %.lr.ph ]
  %.0913.unr = phi i32 [ 1, %1 ], [ %14, %.lr.ph ]
  %.01012.unr = phi i32 [ 0, %1 ], [ %12, %.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.unr-lcssa, %.lr.ph.epil
  %.0913.epil = phi i32 [ %6, %.lr.ph.epil ], [ %.0913.unr, %._crit_edge.unr-lcssa ]
  %.01012.epil = phi i32 [ %.0913.epil, %.lr.ph.epil ], [ %.01012.unr, %._crit_edge.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.unr-lcssa ]
  %5 = add nsw i32 %.0913.epil, %.01012.epil
  %6 = srem i32 %5, 10
  %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 !5

._crit_edge:                                      ; preds = %.lr.ph.epil, %._crit_edge.unr-lcssa
  %.lcssa = phi i32 [ %.lcssa.ph, %._crit_edge.unr-lcssa ], [ %6, %.lr.ph.epil ]
  ret i32 %.lcssa

.lr.ph:                                           ; preds = %.lr.ph, %.new
  %.0913 = phi i32 [ 1, %.new ], [ %14, %.lr.ph ]
  %.01012 = phi i32 [ 0, %.new ], [ %12, %.lr.ph ]
  %niter = phi i64 [ 0, %.new ], [ %niter.next.3, %.lr.ph ]
  %7 = add nsw i32 %.0913, %.01012
  %8 = srem i32 %7, 10
  %9 = add nsw i32 %8, %.0913
  %10 = srem i32 %9, 10
  %11 = add nsw i32 %10, %8
  %12 = srem i32 %11, 10
  %13 = add nsw i32 %12, %10
  %14 = srem i32 %13, 10
  %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.unr-lcssa, label %.lr.ph, !llvm.loop !7
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write)
declare void @llvm.assume(i1 noundef) #1

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" }
attributes #1 = { nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write) }

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


; Effective O3 passes: GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,LCSSAPass,LoopRotatePass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass