; LLVM IR from tangjz/acm-icpc :: codeforces/complete/938G.ll (Z8dsu_findi)

; 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"

%"struct.std::pair" = type { i32, i32 }

@dsu = external dso_local global [200001 x i32], align 16
@msk = external dso_local global [200001 x i32], align 16

; Function Attrs: mustprogress uwtable
define dso_local i64 @_Z8dsu_findi(i32 noundef %0) #0 {
  %2 = alloca %"struct.std::pair", align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #3
  store i32 0, ptr %4, align 4, !tbaa !5
  br label %5

5:                                                ; preds = %12, %1
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = sext i32 %6 to i64
  %8 = getelementptr inbounds [200001 x i32], ptr @dsu, i64 0, i64 %7
  %9 = load i32, ptr %8, align 4, !tbaa !5
  %10 = icmp sge i32 %9, 0
  br i1 %10, label %11, label %23

11:                                               ; preds = %5
  br label %12

12:                                               ; preds = %11
  %13 = load i32, ptr %3, align 4, !tbaa !5
  %14 = sext i32 %13 to i64
  %15 = getelementptr inbounds [200001 x i32], ptr @msk, i64 0, i64 %14
  %16 = load i32, ptr %15, align 4, !tbaa !5
  %17 = load i32, ptr %4, align 4, !tbaa !5
  %18 = xor i32 %17, %16
  store i32 %18, ptr %4, align 4, !tbaa !5
  %19 = load i32, ptr %3, align 4, !tbaa !5
  %20 = sext i32 %19 to i64
  %21 = getelementptr inbounds [200001 x i32], ptr @dsu, i64 0, i64 %20
  %22 = load i32, ptr %21, align 4, !tbaa !5
  store i32 %22, ptr %3, align 4, !tbaa !5
  br label %5, !llvm.loop !9

23:                                               ; preds = %5
  call void @_ZNSt4pairIiiEC2IRiS2_TnNSt9enable_ifIXaaclsr5_PCCPE22_MoveConstructiblePairIT_T0_EEclsr5_PCCPE30_ImplicitlyMoveConvertiblePairIS4_S5_EEEbE4typeELb1EEEOS4_OS5_(ptr noundef nonnull align 4 dereferenceable(8) %2, ptr noundef nonnull align 4 dereferenceable(4) %3, ptr noundef nonnull align 4 dereferenceable(4) %4)
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #3
  %24 = load i64, ptr %2, align 4
  ret i64 %24
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZNSt4pairIiiEC2IRiS2_TnNSt9enable_ifIXaaclsr5_PCCPE22_MoveConstructiblePairIT_T0_EEclsr5_PCCPE30_ImplicitlyMoveConvertiblePairIS4_S5_EEEbE4typeELb1EEEOS4_OS5_(ptr noundef nonnull align 4 dereferenceable(8), ptr noundef nonnull align 4 dereferenceable(4), ptr noundef nonnull align 4 dereferenceable(4)) unnamed_addr #2 align 2

; 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 = { 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 #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++ 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"

%"struct.std::pair" = type { i32, i32 }

@dsu = external dso_local local_unnamed_addr global [200001 x i32], align 16
@msk = external dso_local local_unnamed_addr global [200001 x i32], align 16

; Function Attrs: mustprogress nounwind uwtable
define dso_local i64 @_Z8dsu_findi(i32 noundef %0) local_unnamed_addr #0 {
  %2 = alloca %"struct.std::pair", align 8
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %4) #2
  %5 = sext i32 %0 to i64
  %6 = getelementptr inbounds [200001 x i32], ptr @dsu, i64 0, i64 %5
  %7 = load i32, ptr %6, align 4, !tbaa !5
  %8 = icmp sgt i32 %7, -1
  br i1 %8, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %1, %.lr.ph
  %9 = phi i32 [ %17, %.lr.ph ], [ %7, %1 ]
  %10 = phi i64 [ %15, %.lr.ph ], [ %5, %1 ]
  %11 = phi i32 [ %14, %.lr.ph ], [ 0, %1 ]
  %12 = getelementptr inbounds [200001 x i32], ptr @msk, i64 0, i64 %10
  %13 = load i32, ptr %12, align 4, !tbaa !5
  %14 = xor i32 %11, %13
  %15 = zext nneg i32 %9 to i64
  %16 = getelementptr inbounds [200001 x i32], ptr @dsu, i64 0, i64 %15
  %17 = load i32, ptr %16, align 4, !tbaa !5
  %18 = icmp sgt i32 %17, -1
  br i1 %18, label %.lr.ph, label %._crit_edge, !llvm.loop !9

._crit_edge:                                      ; preds = %.lr.ph, %1
  %.lcssa2 = phi i32 [ 0, %1 ], [ %14, %.lr.ph ]
  %.lcssa = phi i32 [ %0, %1 ], [ %9, %.lr.ph ]
  store i32 %.lcssa, ptr %3, align 4, !tbaa !5
  store i32 %.lcssa2, ptr %4, align 4, !tbaa !5
  call void @_ZNSt4pairIiiEC2IRiS2_TnNSt9enable_ifIXaaclsr5_PCCPE22_MoveConstructiblePairIT_T0_EEclsr5_PCCPE30_ImplicitlyMoveConvertiblePairIS4_S5_EEEbE4typeELb1EEEOS4_OS5_(ptr noundef nonnull align 4 dereferenceable(8) %2, ptr noundef nonnull align 4 dereferenceable(4) %3, ptr noundef nonnull align 4 dereferenceable(4) %4)
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %4) #2
  %19 = load i64, ptr %2, align 8
  ret i64 %19
}

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_ZNSt4pairIiiEC2IRiS2_TnNSt9enable_ifIXaaclsr5_PCCPE22_MoveConstructiblePairIT_T0_EEclsr5_PCCPE30_ImplicitlyMoveConvertiblePairIS4_S5_EEEbE4typeELb1EEEOS4_OS5_(ptr noundef nonnull align 4 dereferenceable(8), ptr noundef nonnull align 4 dereferenceable(4), ptr noundef nonnull align 4 dereferenceable(4)) unnamed_addr #0 align 2

; Function Attrs: mustprogress 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 = { mustprogress 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"}


; Effective O3 passes: DSEPass,EarlyCSEPass,GVNPass,GlobalOptPass,InferAlignmentPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SimplifyCFGPass