; LLVM IR from chachaxw/data-structure-and-algorithm :: leetcode/dynamic_programming/dp_fibonacci_numbers.ll (ZN8Solution3fibEi)

; 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
define dso_local noundef i32 @_ZN8Solution3fibEi(ptr noundef nonnull align 1 dereferenceable(1) %0, i32 noundef %1) #0 align 2 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !9
  %5 = load ptr, ptr %3, align 8
  %6 = load i32, ptr %4, align 4, !tbaa !9
  %7 = icmp slt i32 %6, 2
  br i1 %7, label %8, label %10

8:                                                ; preds = %2
  %9 = load i32, ptr %4, align 4, !tbaa !9
  br label %18

10:                                               ; preds = %2
  %11 = load i32, ptr %4, align 4, !tbaa !9
  %12 = sub nsw i32 %11, 1
  %13 = call noundef i32 @_ZN8Solution3fibEi(ptr noundef nonnull align 1 dereferenceable(1) %5, i32 noundef %12)
  %14 = load i32, ptr %4, align 4, !tbaa !9
  %15 = sub nsw i32 %14, 2
  %16 = call noundef i32 @_ZN8Solution3fibEi(ptr noundef nonnull align 1 dereferenceable(1) %5, i32 noundef %15)
  %17 = add nsw i32 %13, %16
  br label %18

18:                                               ; preds = %10, %8
  %19 = phi i32 [ %9, %8 ], [ %17, %10 ]
  ret i32 %19
}

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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}


; 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 nosync nounwind willreturn memory(none) uwtable
define dso_local noundef i32 @_ZN8Solution3fibEi(ptr nocapture noundef nonnull readnone align 1 dereferenceable(1) %0, i32 noundef %1) local_unnamed_addr #0 align 2 {
  %3 = icmp slt i32 %1, 2
  br i1 %3, label %tailrecurse._crit_edge, label %tailrecurse

tailrecurse:                                      ; preds = %2, %tailrecurse
  %.tr46 = phi i32 [ %6, %tailrecurse ], [ %1, %2 ]
  %accumulator.tr5 = phi i32 [ %7, %tailrecurse ], [ 0, %2 ]
  %4 = add nsw i32 %.tr46, -1
  %5 = tail call noundef i32 @_ZN8Solution3fibEi(ptr noundef nonnull align 1 dereferenceable(1) %0, i32 noundef %4)
  %6 = add nsw i32 %.tr46, -2
  %7 = add nsw i32 %5, %accumulator.tr5
  %8 = icmp ult i32 %.tr46, 4
  br i1 %8, label %tailrecurse._crit_edge, label %tailrecurse

tailrecurse._crit_edge:                           ; preds = %tailrecurse, %2
  %accumulator.tr.lcssa = phi i32 [ 0, %2 ], [ %7, %tailrecurse ]
  %.tr4.lcssa = phi i32 [ %1, %2 ], [ %6, %tailrecurse ]
  %accumulator.ret.tr = add nsw i32 %.tr4.lcssa, %accumulator.tr.lcssa
  ret i32 %accumulator.ret.tr
}

attributes #0 = { mustprogress nofree 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)"}


; Effective O3 passes: CorrelatedValuePropagationPass,GVNPass,GlobalOptPass,IPSCCPPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass