; LLVM IR from JessonYue/LeetCodeLearning :: Array/liuchang/day2 (solution)

; 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: nounwind uwtable
define dso_local i32 @climbStairs(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  %4 = alloca i64, align 8
  %5 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  %6 = load i32, ptr %2, align 4, !tbaa !5
  %7 = add nsw i32 %6, 1
  %8 = zext i32 %7 to i64
  %9 = call ptr @llvm.stacksave.p0()
  store ptr %9, ptr %3, align 8
  %10 = alloca i32, i64 %8, align 16
  store i64 %8, ptr %4, align 8
  %11 = getelementptr inbounds i32, ptr %10, i64 0
  store i32 1, ptr %11, align 16, !tbaa !5
  %12 = getelementptr inbounds i32, ptr %10, i64 1
  store i32 1, ptr %12, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  store i32 2, ptr %5, align 4, !tbaa !5
  br label %13

13:                                               ; preds = %33, %1
  %14 = load i32, ptr %5, align 4, !tbaa !5
  %15 = load i32, ptr %2, align 4, !tbaa !5
  %16 = icmp sle i32 %14, %15
  br i1 %16, label %18, label %17

17:                                               ; preds = %13
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  br label %36

18:                                               ; preds = %13
  %19 = load i32, ptr %5, align 4, !tbaa !5
  %20 = sub nsw i32 %19, 1
  %21 = sext i32 %20 to i64
  %22 = getelementptr inbounds i32, ptr %10, i64 %21
  %23 = load i32, ptr %22, align 4, !tbaa !5
  %24 = load i32, ptr %5, align 4, !tbaa !5
  %25 = sub nsw i32 %24, 2
  %26 = sext i32 %25 to i64
  %27 = getelementptr inbounds i32, ptr %10, i64 %26
  %28 = load i32, ptr %27, align 4, !tbaa !5
  %29 = add nsw i32 %23, %28
  %30 = load i32, ptr %5, align 4, !tbaa !5
  %31 = sext i32 %30 to i64
  %32 = getelementptr inbounds i32, ptr %10, i64 %31
  store i32 %29, ptr %32, align 4, !tbaa !5
  br label %33

33:                                               ; preds = %18
  %34 = load i32, ptr %5, align 4, !tbaa !5
  %35 = add nsw i32 %34, 1
  store i32 %35, ptr %5, align 4, !tbaa !5
  br label %13, !llvm.loop !9

36:                                               ; preds = %17
  %37 = load i32, ptr %2, align 4, !tbaa !5
  %38 = sext i32 %37 to i64
  %39 = getelementptr inbounds i32, ptr %10, i64 %38
  %40 = load i32, ptr %39, align 4, !tbaa !5
  %41 = load ptr, ptr %3, align 8
  call void @llvm.stackrestore.p0(ptr %41)
  ret i32 %40
}

; Function Attrs: nocallback nofree nosync nounwind willreturn
declare ptr @llvm.stacksave.p0() #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn
declare void @llvm.stackrestore.p0(ptr) #1

attributes #0 = { 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 #1 = { nocallback nofree nosync nounwind willreturn }
attributes #2 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #3 = { 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/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: nofree norecurse nosync nounwind memory(none) uwtable
define dso_local i32 @climbStairs(i32 noundef %0) local_unnamed_addr #0 {
  %2 = add i32 %0, 1
  %3 = zext i32 %2 to i64
  %4 = alloca i32, i64 %3, align 16
  store i32 1, ptr %4, align 16, !tbaa !5
  %5 = getelementptr inbounds i8, ptr %4, i64 4
  store i32 1, ptr %5, align 4, !tbaa !5
  %.not9 = icmp slt i32 %0, 2
  br i1 %.not9, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %1
  %scevgep = getelementptr i8, ptr %4, i64 4
  %load_initial = load i32, ptr %scevgep, align 4
  %6 = add nsw i64 %3, -2
  %7 = add nsw i64 %3, -3
  %xtraiter = and i64 %6, 3
  %8 = icmp ult i64 %7, 3
  br i1 %8, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i64 %6, -4
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %store_forwarded.unr = phi i32 [ %load_initial, %.lr.ph.preheader ], [ %32, %.lr.ph ]
  %indvars.iv.unr = phi i64 [ 2, %.lr.ph.preheader ], [ %indvars.iv.next.3, %.lr.ph ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil
  %store_forwarded.epil = phi i32 [ %12, %.lr.ph.epil ], [ %store_forwarded.unr, %._crit_edge.loopexit.unr-lcssa ]
  %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil, %.lr.ph.epil ], [ %indvars.iv.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %9 = getelementptr i32, ptr %4, i64 %indvars.iv.epil
  %10 = getelementptr i8, ptr %9, i64 -8
  %11 = load i32, ptr %10, align 4, !tbaa !5
  %12 = add nsw i32 %11, %store_forwarded.epil
  store i32 %12, ptr %9, align 4, !tbaa !5
  %indvars.iv.next.epil = add nuw nsw i64 %indvars.iv.epil, 1
  %epil.iter.next = add i64 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i64 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge, label %.lr.ph.epil, !llvm.loop !9

._crit_edge:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil, %1
  %13 = sext i32 %0 to i64
  %14 = getelementptr inbounds i32, ptr %4, i64 %13
  %15 = load i32, ptr %14, align 4, !tbaa !5
  ret i32 %15

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %store_forwarded = phi i32 [ %load_initial, %.lr.ph.preheader.new ], [ %32, %.lr.ph ]
  %indvars.iv = phi i64 [ 2, %.lr.ph.preheader.new ], [ %indvars.iv.next.3, %.lr.ph ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.3, %.lr.ph ]
  %16 = getelementptr i32, ptr %4, i64 %indvars.iv
  %17 = getelementptr i8, ptr %16, i64 -8
  %18 = load i32, ptr %17, align 8, !tbaa !5
  %19 = add nsw i32 %18, %store_forwarded
  store i32 %19, ptr %16, align 8, !tbaa !5
  %indvars.iv.next = or disjoint i64 %indvars.iv, 1
  %20 = getelementptr i32, ptr %4, i64 %indvars.iv.next
  %21 = getelementptr i8, ptr %20, i64 -8
  %22 = load i32, ptr %21, align 4, !tbaa !5
  %23 = add nsw i32 %22, %19
  store i32 %23, ptr %20, align 4, !tbaa !5
  %24 = getelementptr i32, ptr %4, i64 %indvars.iv
  %25 = getelementptr i8, ptr %24, i64 8
  %26 = load i32, ptr %24, align 8, !tbaa !5
  %27 = add nsw i32 %26, %23
  store i32 %27, ptr %25, align 8, !tbaa !5
  %28 = getelementptr i32, ptr %4, i64 %indvars.iv
  %29 = getelementptr i8, ptr %28, i64 12
  %30 = getelementptr i8, ptr %28, i64 4
  %31 = load i32, ptr %30, align 4, !tbaa !5
  %32 = add nsw i32 %31, %27
  store i32 %32, ptr %29, align 4, !tbaa !5
  %indvars.iv.next.3 = add nuw nsw i64 %indvars.iv, 4
  %niter.next.3 = add i64 %niter, 4
  %niter.ncmp.3 = icmp eq i64 %niter.next.3, %unroll_iter
  br i1 %niter.ncmp.3, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !11
}

attributes #0 = { nofree norecurse nosync nounwind 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 = !{!6, !6, i64 0}
!6 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.unroll.disable"}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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