; LLVM IR from ravireddy07/cpp-book :: src/Common-Problems/StaircaseRecursion.ll (Z14countStairPathiii)

; 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 @_Z14countStairPathiii(i32 noundef %0, i32 noundef %1, i32 noundef %2) #0 {
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  %9 = alloca i32, align 4
  store i32 %0, ptr %5, align 4, !tbaa !5
  store i32 %1, ptr %6, align 4, !tbaa !5
  store i32 %2, ptr %7, align 4, !tbaa !5
  %10 = load i32, ptr %6, align 4, !tbaa !5
  %11 = load i32, ptr %5, align 4, !tbaa !5
  %12 = icmp sgt i32 %10, %11
  br i1 %12, label %13, label %14

13:                                               ; preds = %3
  store i32 0, ptr %4, align 4
  br label %39

14:                                               ; preds = %3
  %15 = load i32, ptr %6, align 4, !tbaa !5
  %16 = load i32, ptr %5, align 4, !tbaa !5
  %17 = icmp eq i32 %15, %16
  br i1 %17, label %18, label %19

18:                                               ; preds = %14
  store i32 1, ptr %4, align 4
  br label %39

19:                                               ; preds = %14
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #2
  store i32 0, ptr %8, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #2
  store i32 1, ptr %9, align 4, !tbaa !5
  br label %20

20:                                               ; preds = %34, %19
  %21 = load i32, ptr %9, align 4, !tbaa !5
  %22 = load i32, ptr %7, align 4, !tbaa !5
  %23 = icmp sle i32 %21, %22
  br i1 %23, label %25, label %24

24:                                               ; preds = %20
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #2
  br label %37

25:                                               ; preds = %20
  %26 = load i32, ptr %5, align 4, !tbaa !5
  %27 = load i32, ptr %6, align 4, !tbaa !5
  %28 = load i32, ptr %9, align 4, !tbaa !5
  %29 = add nsw i32 %27, %28
  %30 = load i32, ptr %7, align 4, !tbaa !5
  %31 = call noundef i32 @_Z14countStairPathiii(i32 noundef %26, i32 noundef %29, i32 noundef %30)
  %32 = load i32, ptr %8, align 4, !tbaa !5
  %33 = add nsw i32 %32, %31
  store i32 %33, ptr %8, align 4, !tbaa !5
  br label %34

34:                                               ; preds = %25
  %35 = load i32, ptr %9, align 4, !tbaa !5
  %36 = add nsw i32 %35, 1
  store i32 %36, ptr %9, align 4, !tbaa !5
  br label %20, !llvm.loop !9

37:                                               ; preds = %24
  %38 = load i32, ptr %8, align 4, !tbaa !5
  store i32 %38, ptr %4, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #2
  br label %39

39:                                               ; preds = %37, %18, %13
  %40 = load i32, ptr %4, align 4
  ret i32 %40
}

; 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 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 = 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 nosync nounwind willreturn memory(none) uwtable
define dso_local noundef i32 @_Z14countStairPathiii(i32 noundef %0, i32 noundef %1, i32 noundef %2) local_unnamed_addr #0 {
  %4 = icmp sgt i32 %1, %0
  br i1 %4, label %.loopexit, label %5

5:                                                ; preds = %3
  %6 = icmp eq i32 %1, %0
  br i1 %6, label %.loopexit, label %.preheader

.preheader:                                       ; preds = %5
  %.not19 = icmp slt i32 %2, 1
  br i1 %.not19, label %.loopexit, label %.lr.ph

.lr.ph:                                           ; preds = %.preheader, %.lr.ph
  %.021 = phi i32 [ %10, %.lr.ph ], [ 1, %.preheader ]
  %.01420 = phi i32 [ %9, %.lr.ph ], [ 0, %.preheader ]
  %7 = add nsw i32 %.021, %1
  %8 = tail call noundef i32 @_Z14countStairPathiii(i32 noundef %0, i32 noundef %7, i32 noundef %2)
  %9 = add nsw i32 %8, %.01420
  %10 = add nuw i32 %.021, 1
  %exitcond.not = icmp eq i32 %.021, %2
  br i1 %exitcond.not, label %.loopexit, label %.lr.ph, !llvm.loop !5

.loopexit:                                        ; preds = %.lr.ph, %.preheader, %5, %3
  %.015 = phi i32 [ 0, %3 ], [ 1, %5 ], [ 0, %.preheader ], [ %9, %.lr.ph ]
  ret i32 %.015
}

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)"}
!5 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass