; LLVM IR from tangjz/acm-icpc :: lydsy/3607.ll (Z11getFarthestPi)

; 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"

@n = external dso_local global i32, align 4

; 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 @_Z11getFarthestPi(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  store i32 1, ptr %3, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 2, ptr %4, align 4, !tbaa !9
  br label %5

5:                                                ; preds = %25, %1
  %6 = load i32, ptr %4, align 4, !tbaa !9
  %7 = load i32, ptr @n, align 4, !tbaa !9
  %8 = icmp sle 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 %28

10:                                               ; preds = %5
  %11 = load ptr, ptr %2, align 8, !tbaa !5
  %12 = load i32, ptr %4, align 4, !tbaa !9
  %13 = sext i32 %12 to i64
  %14 = getelementptr inbounds i32, ptr %11, i64 %13
  %15 = load i32, ptr %14, align 4, !tbaa !9
  %16 = load ptr, ptr %2, align 8, !tbaa !5
  %17 = load i32, ptr %3, align 4, !tbaa !9
  %18 = sext i32 %17 to i64
  %19 = getelementptr inbounds i32, ptr %16, i64 %18
  %20 = load i32, ptr %19, align 4, !tbaa !9
  %21 = icmp sgt i32 %15, %20
  br i1 %21, label %22, label %24

22:                                               ; preds = %10
  %23 = load i32, ptr %4, align 4, !tbaa !9
  store i32 %23, ptr %3, align 4, !tbaa !9
  br label %24

24:                                               ; preds = %22, %10
  br label %25

25:                                               ; preds = %24
  %26 = load i32, ptr %4, align 4, !tbaa !9
  %27 = add nsw i32 %26, 1
  store i32 %27, ptr %4, align 4, !tbaa !9
  br label %5, !llvm.loop !11

28:                                               ; preds = %9
  %29 = load i32, ptr %3, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  ret i32 %29
}

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"

@n = external dso_local local_unnamed_addr global i32, align 4

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(read, inaccessiblemem: none) uwtable
define dso_local noundef i32 @_Z11getFarthestPi(ptr nocapture noundef readonly %0) local_unnamed_addr #0 {
  %2 = load i32, ptr @n, align 4, !tbaa !5
  %.not8 = icmp slt i32 %2, 2
  br i1 %.not8, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %1
  %3 = add nuw i32 %2, 1
  %wide.trip.count = zext i32 %3 to i64
  %4 = add nsw i64 %wide.trip.count, -2
  %5 = add nsw i64 %wide.trip.count, -3
  %xtraiter = and i64 %4, 3
  %6 = icmp ult i64 %5, 3
  br i1 %6, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

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

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %spec.select.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %spec.select.3, %.lr.ph ]
  %indvars.iv.unr = phi i64 [ 2, %.lr.ph.preheader ], [ %indvars.iv.next.3, %.lr.ph ]
  %.079.unr = phi i32 [ 1, %.lr.ph.preheader ], [ %spec.select.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
  %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil, %.lr.ph.epil ], [ %indvars.iv.unr, %._crit_edge.loopexit.unr-lcssa ]
  %.079.epil = phi i32 [ %spec.select.epil, %.lr.ph.epil ], [ %.079.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %7 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.epil
  %8 = load i32, ptr %7, align 4, !tbaa !5
  %9 = sext i32 %.079.epil to i64
  %10 = getelementptr inbounds i32, ptr %0, i64 %9
  %11 = load i32, ptr %10, align 4, !tbaa !5
  %12 = icmp sgt i32 %8, %11
  %13 = trunc nuw nsw i64 %indvars.iv.epil to i32
  %spec.select.epil = select i1 %12, i32 %13, i32 %.079.epil
  %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
  %.07.lcssa = phi i32 [ 1, %1 ], [ %spec.select.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %spec.select.epil, %.lr.ph.epil ]
  ret i32 %.07.lcssa

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %indvars.iv = phi i64 [ 2, %.lr.ph.preheader.new ], [ %indvars.iv.next.3, %.lr.ph ]
  %.079 = phi i32 [ 1, %.lr.ph.preheader.new ], [ %spec.select.3, %.lr.ph ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.3, %.lr.ph ]
  %14 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv
  %15 = load i32, ptr %14, align 4, !tbaa !5
  %16 = sext i32 %.079 to i64
  %17 = getelementptr inbounds i32, ptr %0, i64 %16
  %18 = load i32, ptr %17, align 4, !tbaa !5
  %19 = icmp sgt i32 %15, %18
  %20 = trunc nuw nsw i64 %indvars.iv to i32
  %spec.select = select i1 %19, i32 %20, i32 %.079
  %indvars.iv.next = or disjoint i64 %indvars.iv, 1
  %21 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next
  %22 = load i32, ptr %21, align 4, !tbaa !5
  %23 = sext i32 %spec.select to i64
  %24 = getelementptr inbounds i32, ptr %0, i64 %23
  %25 = load i32, ptr %24, align 4, !tbaa !5
  %26 = icmp sgt i32 %22, %25
  %27 = trunc nuw nsw i64 %indvars.iv.next to i32
  %spec.select.1 = select i1 %26, i32 %27, i32 %spec.select
  %indvars.iv.next.1 = add nuw nsw i64 %indvars.iv, 2
  %28 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next.1
  %29 = load i32, ptr %28, align 4, !tbaa !5
  %30 = sext i32 %spec.select.1 to i64
  %31 = getelementptr inbounds i32, ptr %0, i64 %30
  %32 = load i32, ptr %31, align 4, !tbaa !5
  %33 = icmp sgt i32 %29, %32
  %34 = trunc nuw nsw i64 %indvars.iv.next.1 to i32
  %spec.select.2 = select i1 %33, i32 %34, i32 %spec.select.1
  %indvars.iv.next.2 = add nuw nsw i64 %indvars.iv, 3
  %35 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next.2
  %36 = load i32, ptr %35, align 4, !tbaa !5
  %37 = sext i32 %spec.select.2 to i64
  %38 = getelementptr inbounds i32, ptr %0, i64 %37
  %39 = load i32, ptr %38, align 4, !tbaa !5
  %40 = icmp sgt i32 %36, %39
  %41 = trunc nuw nsw i64 %indvars.iv.next.2 to i32
  %spec.select.3 = select i1 %40, i32 %41, i32 %spec.select.2
  %indvars.iv.next.3 = add nuw nsw i64 %indvars.iv, 4
  %niter.next.3 = add nuw 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 = { mustprogress nofree norecurse nosync nounwind willreturn memory(read, 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" }

!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.unroll.disable"}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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