; LLVM IR from devparthgarg/Data-Structures-and-Algorithms :: 21. Dynamic Programming/02 Nth Fibonacci/02b Nth Fibonacci.ll (Z3fibi)

; 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"

@dp = external dso_local global [100000 x i32], align 16

; Function Attrs: mustprogress uwtable
define dso_local noundef i32 @_Z3fibi(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %4 = load i32, ptr %3, align 4, !tbaa !5
  %5 = sext i32 %4 to i64
  %6 = getelementptr inbounds [100000 x i32], ptr @dp, i64 0, i64 %5
  %7 = load i32, ptr %6, align 4, !tbaa !5
  %8 = icmp eq i32 %7, -1
  br i1 %8, label %9, label %28

9:                                                ; preds = %1
  %10 = load i32, ptr %3, align 4, !tbaa !5
  %11 = icmp sle i32 %10, 1
  br i1 %11, label %12, label %17

12:                                               ; preds = %9
  %13 = load i32, ptr %3, align 4, !tbaa !5
  %14 = load i32, ptr %3, align 4, !tbaa !5
  %15 = sext i32 %14 to i64
  %16 = getelementptr inbounds [100000 x i32], ptr @dp, i64 0, i64 %15
  store i32 %13, ptr %16, align 4, !tbaa !5
  store i32 %13, ptr %2, align 4
  br label %33

17:                                               ; preds = %9
  %18 = load i32, ptr %3, align 4, !tbaa !5
  %19 = sub nsw i32 %18, 1
  %20 = call noundef i32 @_Z3fibi(i32 noundef %19)
  %21 = load i32, ptr %3, align 4, !tbaa !5
  %22 = sub nsw i32 %21, 2
  %23 = call noundef i32 @_Z3fibi(i32 noundef %22)
  %24 = add nsw i32 %20, %23
  %25 = load i32, ptr %3, align 4, !tbaa !5
  %26 = sext i32 %25 to i64
  %27 = getelementptr inbounds [100000 x i32], ptr @dp, i64 0, i64 %26
  store i32 %24, ptr %27, align 4, !tbaa !5
  store i32 %24, ptr %2, align 4
  br label %33

28:                                               ; preds = %1
  %29 = load i32, ptr %3, align 4, !tbaa !5
  %30 = sext i32 %29 to i64
  %31 = getelementptr inbounds [100000 x i32], ptr @dp, i64 0, i64 %30
  %32 = load i32, ptr %31, align 4, !tbaa !5
  store i32 %32, ptr %2, align 4
  br label %33

33:                                               ; preds = %28, %17, %12
  %34 = load i32, ptr %2, align 4
  ret i32 %34
}

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)"}
!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"

@dp = external dso_local local_unnamed_addr global [100000 x i32], align 16

; Function Attrs: mustprogress nofree nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: none) uwtable
define dso_local noundef i32 @_Z3fibi(i32 noundef %0) local_unnamed_addr #0 {
  %2 = sext i32 %0 to i64
  %3 = getelementptr inbounds [100000 x i32], ptr @dp, i64 0, i64 %2
  %4 = load i32, ptr %3, align 4, !tbaa !5
  %5 = icmp eq i32 %4, -1
  br i1 %5, label %6, label %common.ret

6:                                                ; preds = %1
  %7 = icmp slt i32 %0, 2
  br i1 %7, label %common.ret.sink.split, label %8

common.ret.sink.split:                            ; preds = %6, %8
  %.sink = phi i32 [ %13, %8 ], [ %0, %6 ]
  store i32 %.sink, ptr %3, align 4, !tbaa !5
  br label %common.ret

common.ret:                                       ; preds = %common.ret.sink.split, %1
  %common.ret.op = phi i32 [ %4, %1 ], [ %.sink, %common.ret.sink.split ]
  ret i32 %common.ret.op

8:                                                ; preds = %6
  %9 = add nsw i32 %0, -1
  %10 = tail call noundef i32 @_Z3fibi(i32 noundef %9)
  %11 = add nsw i32 %0, -2
  %12 = tail call noundef i32 @_Z3fibi(i32 noundef %11)
  %13 = add nsw i32 %12, %10
  br label %common.ret.sink.split
}

attributes #0 = { mustprogress nofree nosync nounwind memory(readwrite, argmem: none, inaccessiblemem: 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 = !{!6, !6, i64 0}
!6 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}


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