; LLVM IR from chachaxw/data-structure-and-algorithm :: leetcode/dynamic_programming/dp_climb_stairs.ll (ZN8Solution12climbStairs1Ei)

; 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: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i32 @_ZN8Solution12climbStairs1Ei(ptr noundef nonnull align 1 dereferenceable(1) %0, i32 noundef %1) #1 align 2 {
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca [3 x i32], align 4
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store i32 %1, ptr %5, align 4, !tbaa !9
  %9 = load ptr, ptr %4, align 8
  %10 = load i32, ptr %5, align 4, !tbaa !9
  %11 = icmp slt i32 %10, 2
  br i1 %11, label %12, label %14

12:                                               ; preds = %2
  %13 = load i32, ptr %5, align 4, !tbaa !9
  store i32 %13, ptr %3, align 4
  br label %39

14:                                               ; preds = %2
  call void @llvm.lifetime.start.p0(i64 12, ptr %6) #2
  %15 = getelementptr inbounds [3 x i32], ptr %6, i64 0, i64 1
  store i32 1, ptr %15, align 4, !tbaa !9
  %16 = getelementptr inbounds [3 x i32], ptr %6, i64 0, i64 2
  store i32 2, ptr %16, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #2
  store i32 3, ptr %7, align 4, !tbaa !9
  br label %17

17:                                               ; preds = %33, %14
  %18 = load i32, ptr %7, align 4, !tbaa !9
  %19 = load i32, ptr %5, align 4, !tbaa !9
  %20 = icmp sle i32 %18, %19
  br i1 %20, label %22, label %21

21:                                               ; preds = %17
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #2
  br label %36

22:                                               ; preds = %17
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #2
  %23 = getelementptr inbounds [3 x i32], ptr %6, i64 0, i64 1
  %24 = load i32, ptr %23, align 4, !tbaa !9
  %25 = getelementptr inbounds [3 x i32], ptr %6, i64 0, i64 2
  %26 = load i32, ptr %25, align 4, !tbaa !9
  %27 = add nsw i32 %24, %26
  store i32 %27, ptr %8, align 4, !tbaa !9
  %28 = getelementptr inbounds [3 x i32], ptr %6, i64 0, i64 2
  %29 = load i32, ptr %28, align 4, !tbaa !9
  %30 = getelementptr inbounds [3 x i32], ptr %6, i64 0, i64 1
  store i32 %29, ptr %30, align 4, !tbaa !9
  %31 = load i32, ptr %8, align 4, !tbaa !9
  %32 = getelementptr inbounds [3 x i32], ptr %6, i64 0, i64 2
  store i32 %31, ptr %32, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #2
  br label %33

33:                                               ; preds = %22
  %34 = load i32, ptr %7, align 4, !tbaa !9
  %35 = add nsw i32 %34, 1
  store i32 %35, ptr %7, align 4, !tbaa !9
  br label %17, !llvm.loop !11

36:                                               ; preds = %21
  %37 = getelementptr inbounds [3 x i32], ptr %6, i64 0, i64 2
  %38 = load i32, ptr %37, align 4, !tbaa !9
  store i32 %38, ptr %3, align 4
  call void @llvm.lifetime.end.p0(i64 12, ptr %6) #2
  br label %39

39:                                               ; preds = %36, %12
  %40 = load i32, ptr %3, align 4
  ret i32 %40
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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 = !{!"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}
!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 i32 @_ZN8Solution12climbStairs1Ei(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 %.loopexit, label %.preheader

.preheader:                                       ; preds = %2
  %.not11 = icmp eq i32 %1, 2
  br i1 %.not11, label %.loopexit, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %.preheader
  %4 = add nsw i32 %1, -2
  %5 = add nsw i32 %1, -3
  %xtraiter = and i32 %4, 7
  %6 = icmp ult i32 %5, 7
  br i1 %6, label %.loopexit.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i32 %4, -8
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %.sroa.5.013 = phi i32 [ 2, %.lr.ph.preheader.new ], [ %14, %.lr.ph ]
  %.sroa.2.012 = phi i32 [ 1, %.lr.ph.preheader.new ], [ %13, %.lr.ph ]
  %niter = phi i32 [ 0, %.lr.ph.preheader.new ], [ %niter.next.7, %.lr.ph ]
  %7 = add nsw i32 %.sroa.5.013, %.sroa.2.012
  %8 = add nsw i32 %7, %.sroa.5.013
  %9 = add nsw i32 %8, %7
  %10 = add nsw i32 %9, %8
  %11 = add nsw i32 %10, %9
  %12 = add nsw i32 %11, %10
  %13 = add nsw i32 %12, %11
  %14 = add nsw i32 %13, %12
  %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 %.lr.ph, !llvm.loop !5

.loopexit.loopexit.unr-lcssa:                     ; preds = %.lr.ph, %.lr.ph.preheader
  %.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %14, %.lr.ph ]
  %.sroa.5.013.unr = phi i32 [ 2, %.lr.ph.preheader ], [ %14, %.lr.ph ]
  %.sroa.2.012.unr = phi i32 [ 1, %.lr.ph.preheader ], [ %13, %.lr.ph ]
  %lcmp.mod.not = icmp eq i32 %xtraiter, 0
  br i1 %lcmp.mod.not, label %.loopexit, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %.loopexit.loopexit.unr-lcssa, %.lr.ph.epil
  %.sroa.5.013.epil = phi i32 [ %15, %.lr.ph.epil ], [ %.sroa.5.013.unr, %.loopexit.loopexit.unr-lcssa ]
  %.sroa.2.012.epil = phi i32 [ %.sroa.5.013.epil, %.lr.ph.epil ], [ %.sroa.2.012.unr, %.loopexit.loopexit.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %.loopexit.loopexit.unr-lcssa ]
  %15 = add nsw i32 %.sroa.5.013.epil, %.sroa.2.012.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 %.lr.ph.epil, !llvm.loop !7

.loopexit:                                        ; preds = %.loopexit.loopexit.unr-lcssa, %.lr.ph.epil, %.preheader, %2
  %.0 = phi i32 [ %1, %2 ], [ 2, %.preheader ], [ %.lcssa.ph, %.loopexit.loopexit.unr-lcssa ], [ %15, %.lr.ph.epil ]
  ret i32 %.0
}

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,ReassociatePass,SROAPass,SimplifyCFGPass