; LLVM IR from Chasmiccoder/Algos-for-Amigos :: Mathematics/Series/p01_fibonacci_series.ll (Z28last_digit_of_nth_fib_numberi)

; 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 noundef i32 @_Z28last_digit_of_nth_fib_numberi(i32 noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  store i32 0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 1, ptr %4, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  store i32 0, ptr %5, align 4, !tbaa !5
  br label %7

7:                                                ; preds = %22, %1
  %8 = load i32, ptr %5, align 4, !tbaa !5
  %9 = load i32, ptr %2, align 4, !tbaa !5
  %10 = icmp slt i32 %8, %9
  br i1 %10, label %12, label %11

11:                                               ; preds = %7
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  br label %25

12:                                               ; preds = %7
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #2
  %13 = load i32, ptr %4, align 4, !tbaa !5
  %14 = srem i32 %13, 10
  store i32 %14, ptr %6, align 4, !tbaa !5
  %15 = load i32, ptr %3, align 4, !tbaa !5
  %16 = srem i32 %15, 10
  store i32 %16, ptr %4, align 4, !tbaa !5
  %17 = load i32, ptr %3, align 4, !tbaa !5
  %18 = srem i32 %17, 10
  %19 = load i32, ptr %6, align 4, !tbaa !5
  %20 = srem i32 %19, 10
  %21 = add nsw i32 %18, %20
  store i32 %21, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #2
  br label %22

22:                                               ; preds = %12
  %23 = load i32, ptr %5, align 4, !tbaa !5
  %24 = add nsw i32 %23, 1
  store i32 %24, ptr %5, align 4, !tbaa !5
  br label %7, !llvm.loop !9

25:                                               ; preds = %11
  %26 = load i32, ptr %3, align 4, !tbaa !5
  %27 = srem i32 %26, 10
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  ret i32 %27
}

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 = !{!"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"

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none) uwtable
define dso_local noundef range(i32 -9, 10) i32 @_Z28last_digit_of_nth_fib_numberi(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp sgt i32 %0, 0
  br i1 %2, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %1
  %xtraiter = and i32 %0, 3
  %3 = icmp ult i32 %0, 4
  br i1 %3, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i32 %0, 2147483644
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %14, %.lr.ph ]
  %.012.unr = phi i32 [ 0, %.lr.ph.preheader ], [ %14, %.lr.ph ]
  %.0910.unr = phi i32 [ 1, %.lr.ph.preheader ], [ %13, %.lr.ph ]
  %lcmp.mod.not = icmp eq i32 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge.loopexit, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil
  %.012.epil = phi i32 [ %5, %.lr.ph.epil ], [ %.012.unr, %._crit_edge.loopexit.unr-lcssa ]
  %.0910.epil = phi i32 [ %4, %.lr.ph.epil ], [ %.0910.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %4 = srem i32 %.012.epil, 10
  %5 = add nsw i32 %4, %.0910.epil
  %epil.iter.next = add i32 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i32 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge.loopexit, label %.lr.ph.epil, !llvm.loop !5

._crit_edge.loopexit:                             ; preds = %.lr.ph.epil, %._crit_edge.loopexit.unr-lcssa
  %.lcssa = phi i32 [ %.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %5, %.lr.ph.epil ]
  %.lhs.trunc = trunc nsw i32 %.lcssa to i8
  %6 = srem i8 %.lhs.trunc, 10
  %.sext = sext i8 %6 to i32
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %1
  %.0.lcssa = phi i32 [ 0, %1 ], [ %.sext, %._crit_edge.loopexit ]
  ret i32 %.0.lcssa

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %.012 = phi i32 [ 0, %.lr.ph.preheader.new ], [ %14, %.lr.ph ]
  %.0910 = phi i32 [ 1, %.lr.ph.preheader.new ], [ %13, %.lr.ph ]
  %niter = phi i32 [ 0, %.lr.ph.preheader.new ], [ %niter.next.3, %.lr.ph ]
  %7 = srem i32 %.012, 10
  %8 = add nsw i32 %7, %.0910
  %9 = srem i32 %8, 10
  %10 = add nsw i32 %9, %7
  %11 = srem i32 %10, 10
  %12 = add nsw i32 %11, %9
  %13 = srem i32 %12, 10
  %14 = add nsw i32 %13, %11
  %niter.next.3 = add i32 %niter, 4
  %niter.ncmp.3 = icmp eq i32 %niter.next.3, %unroll_iter
  br i1 %niter.ncmp.3, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !7
}

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


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