; LLVM IR from next-step-for-interview-prep/Coding-Ninjas-DSA-course_code_and_notes_cpp :: Milestone-3=DSA/lecture-notes/lecture-3=Recursion-1/code.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 uwtable
declare dso_local noundef i32 @_Z3fibi(i32 noundef) #0

; 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

; Function Attrs: mustprogress uwtable
define dso_local noundef i32 @_Z4fib2i(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = icmp eq i32 %6, 0
  br i1 %7, label %8, label %9

8:                                                ; preds = %1
  store i32 0, ptr %2, align 4
  br label %23

9:                                                ; preds = %1
  %10 = load i32, ptr %3, align 4, !tbaa !5
  %11 = icmp eq i32 %10, 1
  br i1 %11, label %12, label %13

12:                                               ; preds = %9
  store i32 1, ptr %2, align 4
  br label %23

13:                                               ; preds = %9
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  %14 = load i32, ptr %3, align 4, !tbaa !5
  %15 = sub nsw i32 %14, 1
  %16 = call noundef i32 @_Z3fibi(i32 noundef %15)
  store i32 %16, ptr %4, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  %17 = load i32, ptr %3, align 4, !tbaa !5
  %18 = sub nsw i32 %17, 2
  %19 = call noundef i32 @_Z3fibi(i32 noundef %18)
  store i32 %19, ptr %5, align 4, !tbaa !5
  %20 = load i32, ptr %4, align 4, !tbaa !5
  %21 = load i32, ptr %5, align 4, !tbaa !5
  %22 = add nsw i32 %20, %21
  store i32 %22, ptr %2, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %23

23:                                               ; preds = %13, %12, %8
  %24 = load i32, ptr %2, align 4
  ret i32 %24
}

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" }
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"}


; 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 uwtable
declare dso_local noundef i32 @_Z3fibi(i32 noundef) local_unnamed_addr #0

; Function Attrs: mustprogress uwtable
define dso_local noundef i32 @_Z4fib2i(i32 noundef %0) local_unnamed_addr #0 {
  %switch = icmp ult i32 %0, 2
  br i1 %switch, label %8, label %2

2:                                                ; preds = %1
  %3 = add nsw i32 %0, -1
  %4 = tail call noundef i32 @_Z3fibi(i32 noundef %3)
  %5 = add nsw i32 %0, -2
  %6 = tail call noundef i32 @_Z3fibi(i32 noundef %5)
  %7 = add nsw i32 %6, %4
  br label %8

8:                                                ; preds = %1, %2
  %.0 = phi i32 [ %7, %2 ], [ %0, %1 ]
  ret i32 %.0
}

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)"}


; Effective O3 passes: GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass