; LLVM IR from UtkarshPathrabe/Competitive-Coding :: HackerRank Solutions/Algorithms/Implementation/Cut The Sticks.ll (Z8ValidLeni)

; 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"

@arr = external dso_local global [1005 x i32], align 16

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z8ValidLeni(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  store i32 0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 0, ptr %4, align 4, !tbaa !5
  br label %5

5:                                                ; preds = %20, %1
  %6 = load i32, ptr %4, align 4, !tbaa !5
  %7 = load i32, ptr %2, align 4, !tbaa !5
  %8 = icmp slt i32 %6, %7
  br i1 %8, label %10, label %9

9:                                                ; preds = %5
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %23

10:                                               ; preds = %5
  %11 = load i32, ptr %4, align 4, !tbaa !5
  %12 = sext i32 %11 to i64
  %13 = getelementptr inbounds [1005 x i32], ptr @arr, i64 0, i64 %12
  %14 = load i32, ptr %13, align 4, !tbaa !5
  %15 = icmp sgt i32 %14, 0
  br i1 %15, label %16, label %19

16:                                               ; preds = %10
  %17 = load i32, ptr %3, align 4, !tbaa !5
  %18 = add nsw i32 %17, 1
  store i32 %18, ptr %3, align 4, !tbaa !5
  br label %19

19:                                               ; preds = %16, %10
  br label %20

20:                                               ; preds = %19
  %21 = load i32, ptr %4, align 4, !tbaa !5
  %22 = add nsw i32 %21, 1
  store i32 %22, ptr %4, align 4, !tbaa !5
  br label %5, !llvm.loop !9

23:                                               ; preds = %9
  %24 = load i32, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  ret i32 %24
}

; 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 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 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"

@arr = external dso_local local_unnamed_addr global [1005 x i32], align 16

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(read, argmem: none, inaccessiblemem: none) uwtable
define dso_local noundef i32 @_Z8ValidLeni(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp sgt i32 %0, 0
  br i1 %2, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %1
  %wide.trip.count = zext nneg i32 %0 to i64
  %min.iters.check = icmp ult i32 %0, 8
  br i1 %min.iters.check, label %.lr.ph.preheader12, label %vector.ph

.lr.ph.preheader12:                               ; preds = %middle.block, %.lr.ph.preheader
  %indvars.iv.ph = phi i64 [ 0, %.lr.ph.preheader ], [ %n.vec, %middle.block ]
  %.067.ph = phi i32 [ 0, %.lr.ph.preheader ], [ %12, %middle.block ]
  br label %.lr.ph

vector.ph:                                        ; preds = %.lr.ph.preheader
  %n.vec = and i64 %wide.trip.count, 2147483640
  br label %vector.body

vector.body:                                      ; preds = %vector.body, %vector.ph
  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
  %vec.phi = phi <4 x i32> [ zeroinitializer, %vector.ph ], [ %9, %vector.body ]
  %vec.phi10 = phi <4 x i32> [ zeroinitializer, %vector.ph ], [ %10, %vector.body ]
  %3 = getelementptr inbounds [1005 x i32], ptr @arr, i64 0, i64 %index
  %4 = getelementptr inbounds i8, ptr %3, i64 16
  %wide.load = load <4 x i32>, ptr %3, align 16, !tbaa !5
  %wide.load11 = load <4 x i32>, ptr %4, align 16, !tbaa !5
  %5 = icmp sgt <4 x i32> %wide.load, zeroinitializer
  %6 = icmp sgt <4 x i32> %wide.load11, zeroinitializer
  %7 = zext <4 x i1> %5 to <4 x i32>
  %8 = zext <4 x i1> %6 to <4 x i32>
  %9 = add <4 x i32> %vec.phi, %7
  %10 = add <4 x i32> %vec.phi10, %8
  %index.next = add nuw i64 %index, 8
  %11 = icmp eq i64 %index.next, %n.vec
  br i1 %11, label %middle.block, label %vector.body, !llvm.loop !9

middle.block:                                     ; preds = %vector.body
  %bin.rdx = add <4 x i32> %10, %9
  %12 = tail call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> %bin.rdx)
  %cmp.n = icmp eq i64 %n.vec, %wide.trip.count
  br i1 %cmp.n, label %._crit_edge, label %.lr.ph.preheader12

._crit_edge:                                      ; preds = %.lr.ph, %middle.block, %1
  %.06.lcssa = phi i32 [ 0, %1 ], [ %12, %middle.block ], [ %spec.select, %.lr.ph ]
  ret i32 %.06.lcssa

.lr.ph:                                           ; preds = %.lr.ph.preheader12, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ %indvars.iv.ph, %.lr.ph.preheader12 ]
  %.067 = phi i32 [ %spec.select, %.lr.ph ], [ %.067.ph, %.lr.ph.preheader12 ]
  %13 = getelementptr inbounds [1005 x i32], ptr @arr, i64 0, i64 %indvars.iv
  %14 = load i32, ptr %13, align 4, !tbaa !5
  %15 = icmp sgt i32 %14, 0
  %16 = zext i1 %15 to i32
  %spec.select = add nuw nsw i32 %.067, %16
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %exitcond.not = icmp eq i64 %indvars.iv.next, %wide.trip.count
  br i1 %exitcond.not, label %._crit_edge, label %.lr.ph, !llvm.loop !13
}

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i32 @llvm.vector.reduce.add.v4i32(<4 x i32>) #1

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(read, 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" }
attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }

!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, !11, !12}
!10 = !{!"llvm.loop.mustprogress"}
!11 = !{!"llvm.loop.isvectorized", i32 1}
!12 = !{!"llvm.loop.unroll.runtime.disable"}
!13 = distinct !{!13, !10, !12, !11}


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