; LLVM IR from pranjalwalia/Competitive-programming :: AtCoder/ABC/159/B.ll/Z5checkNSt7 (cxx1112basic_stringIcSt11char_traitsIcESaIcEEE)

; 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: mustprogress uwtable
define dso_local noundef zeroext i1 @_Z5checkNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(ptr noundef %0) #0 {
  %2 = alloca i1, align 1
  %3 = alloca ptr, align 8
  %4 = alloca i64, align 8
  %5 = alloca i64, align 8
  %6 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  %7 = call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  store i64 %7, ptr %4, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #3
  store i64 0, ptr %5, align 8, !tbaa !9
  br label %8

8:                                                ; preds = %27, %1
  %9 = load i64, ptr %5, align 8, !tbaa !9
  %10 = load i64, ptr %4, align 8, !tbaa !9
  %11 = sdiv i64 %10, 2
  %12 = icmp sle i64 %9, %11
  br i1 %12, label %13, label %30

13:                                               ; preds = %8
  %14 = load i64, ptr %5, align 8, !tbaa !9
  %15 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %14)
  %16 = load i8, ptr %15, align 1, !tbaa !11
  %17 = sext i8 %16 to i32
  %18 = load i64, ptr %4, align 8, !tbaa !9
  %19 = load i64, ptr %5, align 8, !tbaa !9
  %20 = sub nsw i64 %18, %19
  %21 = sub nsw i64 %20, 1
  %22 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %21)
  %23 = load i8, ptr %22, align 1, !tbaa !11
  %24 = sext i8 %23 to i32
  %25 = icmp ne i32 %17, %24
  br i1 %25, label %26, label %27

26:                                               ; preds = %13
  store i1 false, ptr %2, align 1
  store i32 1, ptr %6, align 4
  br label %31

27:                                               ; preds = %13
  %28 = load i64, ptr %5, align 8, !tbaa !9
  %29 = add nsw i64 %28, 1
  store i64 %29, ptr %5, align 8, !tbaa !9
  br label %8, !llvm.loop !12

30:                                               ; preds = %8
  store i1 true, ptr %2, align 1
  store i32 1, ptr %6, align 4
  br label %31

31:                                               ; preds = %30, %26
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  %32 = load i1, ptr %2, align 1
  ret i1 %32
}

; 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 noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32)) #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32), i64 noundef) #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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"long long", !7, i64 0}
!11 = !{!7, !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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 nounwind uwtable
define dso_local noundef zeroext i1 @_Z5checkNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(ptr noundef nonnull %0) local_unnamed_addr #0 {
  %2 = tail call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %0) #1
  %3 = sdiv i64 %2, 2
  %.not8 = icmp slt i64 %2, -1
  br i1 %.not8, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %1
  %4 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef 0)
  %5 = load i8, ptr %4, align 1, !tbaa !5
  %6 = add i64 %2, -1
  %7 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %6)
  %8 = load i8, ptr %7, align 1, !tbaa !5
  %.not713 = icmp eq i8 %5, %8
  br i1 %.not713, label %.lr.ph15, label %._crit_edge

.lr.ph15:                                         ; preds = %.lr.ph.preheader, %.lr.ph
  %.0914 = phi i64 [ %9, %.lr.ph ], [ 0, %.lr.ph.preheader ]
  %exitcond = icmp eq i64 %.0914, %3
  br i1 %exitcond, label %._crit_edge.loopexit, label %.lr.ph, !llvm.loop !8

.lr.ph:                                           ; preds = %.lr.ph15
  %9 = add nuw nsw i64 %.0914, 1
  %10 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %9)
  %11 = load i8, ptr %10, align 1, !tbaa !5
  %reass.sub = sub i64 %2, %.0914
  %12 = add i64 %reass.sub, -2
  %13 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %12)
  %14 = load i8, ptr %13, align 1, !tbaa !5
  %.not7 = icmp eq i8 %11, %14
  br i1 %.not7, label %.lr.ph15, label %._crit_edge.loopexit, !llvm.loop !8

._crit_edge.loopexit:                             ; preds = %.lr.ph, %.lr.ph15
  %.not.le = icmp sge i64 %.0914, %3
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %.lr.ph.preheader, %1
  %.not.lcssa = phi i1 [ true, %1 ], [ false, %.lr.ph.preheader ], [ %.not.le, %._crit_edge.loopexit ]
  ret i1 %.not.lcssa
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #0 align 2

; Function Attrs: mustprogress nounwind uwtable
declare noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32), i64 noundef) local_unnamed_addr #0 align 2

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 = { 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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C++ TBAA"}
!8 = distinct !{!8, !9}
!9 = !{!"llvm.loop.mustprogress"}


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