; LLVM IR from PacktPublishing/CPP-Data-Structures-and-Algorithms :: Chapter09/Fibonacci/main.ll (Z4fib2i)

; 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 @_Z4fib2i(i32 noundef %0) #0 {
  %2 = alloca i64, align 8
  %3 = alloca i32, align 4
  %4 = alloca i64, align 8
  %5 = alloca i64, align 8
  %6 = alloca i64, align 8
  %7 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %8 = load i32, ptr %3, align 4, !tbaa !5
  %9 = icmp sle i32 %8, 1
  br i1 %9, label %10, label %11

10:                                               ; preds = %1
  store i64 1, ptr %2, align 8
  br label %28

11:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  store i64 1, ptr %4, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  store i64 1, ptr %5, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  store i64 1, ptr %6, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #2
  store i32 2, ptr %7, align 4, !tbaa !5
  br label %12

12:                                               ; preds = %23, %11
  %13 = load i32, ptr %7, 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 %7) #2
  br label %26

17:                                               ; preds = %12
  %18 = load i64, ptr %4, align 8, !tbaa !9
  %19 = load i64, ptr %5, align 8, !tbaa !9
  %20 = add nsw i64 %18, %19
  store i64 %20, ptr %6, align 8, !tbaa !9
  %21 = load i64, ptr %4, align 8, !tbaa !9
  store i64 %21, ptr %5, align 8, !tbaa !9
  %22 = load i64, ptr %6, align 8, !tbaa !9
  store i64 %22, ptr %4, align 8, !tbaa !9
  br label %23

23:                                               ; preds = %17
  %24 = load i32, ptr %7, align 4, !tbaa !5
  %25 = add nsw i32 %24, 1
  store i32 %25, ptr %7, align 4, !tbaa !5
  br label %12, !llvm.loop !11

26:                                               ; preds = %16
  %27 = load i64, ptr %6, align 8, !tbaa !9
  store i64 %27, ptr %2, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  br label %28

28:                                               ; preds = %26, %10
  %29 = load i64, ptr %2, align 8
  ret i64 %29
}

; 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 = !{!10, !10, i64 0}
!10 = !{!"long long", !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 i64 @_Z4fib2i(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp slt i32 %0, 2
  br i1 %2, label %.loopexit, label %.preheader.preheader

.preheader.preheader:                             ; preds = %1
  %3 = add nsw i32 %0, -1
  %4 = add nsw i32 %0, -2
  %xtraiter = and i32 %3, 7
  %5 = icmp ult i32 %4, 7
  br i1 %5, label %.loopexit.loopexit.unr-lcssa, label %.preheader.preheader.new

.preheader.preheader.new:                         ; preds = %.preheader.preheader
  %unroll_iter = and i32 %3, -8
  br label %.preheader

.preheader:                                       ; preds = %.preheader, %.preheader.preheader.new
  %.01016 = phi i64 [ 1, %.preheader.preheader.new ], [ %13, %.preheader ]
  %.01115 = phi i64 [ 1, %.preheader.preheader.new ], [ %12, %.preheader ]
  %niter = phi i32 [ 0, %.preheader.preheader.new ], [ %niter.next.7, %.preheader ]
  %6 = add nsw i64 %.01016, %.01115
  %7 = add nsw i64 %6, %.01016
  %8 = add nsw i64 %7, %6
  %9 = add nsw i64 %8, %7
  %10 = add nsw i64 %9, %8
  %11 = add nsw i64 %10, %9
  %12 = add nsw i64 %11, %10
  %13 = add nsw i64 %12, %11
  %niter.next.7 = add i32 %niter, 8
  %niter.ncmp.7 = icmp eq i32 %niter.next.7, %unroll_iter
  br i1 %niter.ncmp.7, label %.loopexit.loopexit.unr-lcssa, label %.preheader, !llvm.loop !5

.loopexit.loopexit.unr-lcssa:                     ; preds = %.preheader, %.preheader.preheader
  %.lcssa.ph = phi i64 [ poison, %.preheader.preheader ], [ %13, %.preheader ]
  %.01016.unr = phi i64 [ 1, %.preheader.preheader ], [ %13, %.preheader ]
  %.01115.unr = phi i64 [ 1, %.preheader.preheader ], [ %12, %.preheader ]
  %lcmp.mod.not = icmp eq i32 %xtraiter, 0
  br i1 %lcmp.mod.not, label %.loopexit, label %.preheader.epil

.preheader.epil:                                  ; preds = %.loopexit.loopexit.unr-lcssa, %.preheader.epil
  %.01016.epil = phi i64 [ %14, %.preheader.epil ], [ %.01016.unr, %.loopexit.loopexit.unr-lcssa ]
  %.01115.epil = phi i64 [ %.01016.epil, %.preheader.epil ], [ %.01115.unr, %.loopexit.loopexit.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.preheader.epil ], [ 0, %.loopexit.loopexit.unr-lcssa ]
  %14 = add nsw i64 %.01016.epil, %.01115.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 %.loopexit, label %.preheader.epil, !llvm.loop !7

.loopexit:                                        ; preds = %.loopexit.loopexit.unr-lcssa, %.preheader.epil, %1
  %.013 = phi i64 [ 1, %1 ], [ %.lcssa.ph, %.loopexit.loopexit.unr-lcssa ], [ %14, %.preheader.epil ]
  ret i64 %.013
}

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: GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass