; LLVM IR from kazunetakahashi/atcoder :: 2019/0817_AGC037 (E)

; 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"

%"class.__gnu_cxx::__normal_iterator.0" = type { ptr }

; 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 uwtable
define dso_local noundef signext i8 @_Z12first_letterRKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(ptr noundef nonnull align 8 dereferenceable(32) %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca i8, align 1
  %4 = alloca ptr, align 8
  %5 = alloca %"class.__gnu_cxx::__normal_iterator.0", align 8
  %6 = alloca %"class.__gnu_cxx::__normal_iterator.0", align 8
  %7 = alloca i8, align 1
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 1, ptr %3) #4
  %8 = load ptr, ptr %2, align 8, !tbaa !5
  %9 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %8, i64 noundef 0) #4
  %10 = load i8, ptr %9, align 1, !tbaa !9
  store i8 %10, ptr %3, align 1, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #4
  %11 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %11, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #4
  %12 = load ptr, ptr %4, align 8, !tbaa !5
  %13 = call ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE5beginEv(ptr noundef nonnull align 8 dereferenceable(32) %12) #4
  %14 = getelementptr inbounds %"class.__gnu_cxx::__normal_iterator.0", ptr %5, i32 0, i32 0
  store ptr %13, ptr %14, align 8
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #4
  %15 = load ptr, ptr %4, align 8, !tbaa !5
  %16 = call ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE3endEv(ptr noundef nonnull align 8 dereferenceable(32) %15) #4
  %17 = getelementptr inbounds %"class.__gnu_cxx::__normal_iterator.0", ptr %6, i32 0, i32 0
  store ptr %16, ptr %17, align 8
  br label %18

18:                                               ; preds = %25, %1
  %19 = call noundef zeroext i1 @_ZN9__gnu_cxxneIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEbRKNS_17__normal_iteratorIT_T0_EESE_(ptr noundef nonnull align 8 dereferenceable(8) %5, ptr noundef nonnull align 8 dereferenceable(8) %6) #4
  br i1 %19, label %21, label %20

20:                                               ; preds = %18
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #4
  br label %27

21:                                               ; preds = %18
  call void @llvm.lifetime.start.p0(i64 1, ptr %7) #4
  %22 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNK9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEdeEv(ptr noundef nonnull align 8 dereferenceable(8) %5) #4
  %23 = load i8, ptr %22, align 1, !tbaa !9
  store i8 %23, ptr %7, align 1, !tbaa !9
  %24 = load i8, ptr %7, align 1, !tbaa !9
  call void @_Z6ch_minIcEvRT_S0_(ptr noundef nonnull align 1 dereferenceable(1) %3, i8 noundef signext %24)
  call void @llvm.lifetime.end.p0(i64 1, ptr %7) #4
  br label %25

25:                                               ; preds = %21
  %26 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZN9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEppEv(ptr noundef nonnull align 8 dereferenceable(8) %5) #4
  br label %18

27:                                               ; preds = %20
  %28 = load i8, ptr %3, align 1, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 1, ptr %3) #4
  ret i8 %28
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef nonnull align 1 dereferenceable(1) ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32), i64 noundef) #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE5beginEv(ptr noundef nonnull align 8 dereferenceable(32)) #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE3endEv(ptr noundef nonnull align 8 dereferenceable(32)) #2 align 2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_ZN9__gnu_cxxneIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEbRKNS_17__normal_iteratorIT_T0_EESE_(ptr noundef nonnull align 8 dereferenceable(8), ptr noundef nonnull align 8 dereferenceable(8)) #3

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 1 dereferenceable(1) ptr @_ZNK9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEdeEv(ptr noundef nonnull align 8 dereferenceable(8)) #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_Z6ch_minIcEvRT_S0_(ptr noundef nonnull align 1 dereferenceable(1), i8 noundef signext) #2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 8 dereferenceable(8) ptr @_ZN9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEppEv(ptr noundef nonnull align 8 dereferenceable(8)) #2 align 2

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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 = { inlinehint 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 #4 = { 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 = !{!7, !7, i64 0}


; 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"

%"class.__gnu_cxx::__normal_iterator.0" = type { ptr }

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: mustprogress 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 signext i8 @_Z12first_letterRKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(ptr noundef nonnull align 8 dereferenceable(32) %0) local_unnamed_addr #1 {
  %2 = alloca i8, align 1
  %3 = alloca %"class.__gnu_cxx::__normal_iterator.0", align 8
  %4 = alloca %"class.__gnu_cxx::__normal_iterator.0", align 8
  call void @llvm.lifetime.start.p0(i64 1, ptr nonnull %2) #3
  %5 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef 0) #3
  %6 = load i8, ptr %5, align 1, !tbaa !5
  store i8 %6, ptr %2, align 1, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr nonnull %3) #3
  %7 = tail call ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE5beginEv(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  store ptr %7, ptr %3, align 8
  call void @llvm.lifetime.start.p0(i64 8, ptr nonnull %4) #3
  %8 = tail call ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE3endEv(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  store ptr %8, ptr %4, align 8
  %9 = call noundef zeroext i1 @_ZN9__gnu_cxxneIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEbRKNS_17__normal_iteratorIT_T0_EESE_(ptr noundef nonnull align 8 dereferenceable(8) %3, ptr noundef nonnull align 8 dereferenceable(8) %4) #3
  br i1 %9, label %.lr.ph, label %._crit_edge

._crit_edge.loopexit:                             ; preds = %.lr.ph
  %.pre = load i8, ptr %2, align 1, !tbaa !5
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %1
  %10 = phi i8 [ %.pre, %._crit_edge.loopexit ], [ %6, %1 ]
  call void @llvm.lifetime.end.p0(i64 8, ptr nonnull %4) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr nonnull %3) #3
  call void @llvm.lifetime.end.p0(i64 1, ptr nonnull %2) #3
  ret i8 %10

.lr.ph:                                           ; preds = %1, %.lr.ph
  %11 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNK9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEdeEv(ptr noundef nonnull align 8 dereferenceable(8) %3) #3
  %12 = load i8, ptr %11, align 1, !tbaa !5
  call void @_Z6ch_minIcEvRT_S0_(ptr noundef nonnull align 1 dereferenceable(1) %2, i8 noundef signext %12)
  %13 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZN9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEppEv(ptr noundef nonnull align 8 dereferenceable(8) %3) #3
  %14 = call noundef zeroext i1 @_ZN9__gnu_cxxneIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEbRKNS_17__normal_iteratorIT_T0_EESE_(ptr noundef nonnull align 8 dereferenceable(8) %3, ptr noundef nonnull align 8 dereferenceable(8) %4) #3
  br i1 %14, label %.lr.ph, label %._crit_edge.loopexit
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef nonnull align 1 dereferenceable(1) ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32), i64 noundef) local_unnamed_addr #1 align 2

; Function Attrs: mustprogress nounwind uwtable
declare ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE5beginEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #1 align 2

; Function Attrs: mustprogress nounwind uwtable
declare ptr @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE3endEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #1 align 2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_ZN9__gnu_cxxneIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEbRKNS_17__normal_iteratorIT_T0_EESE_(ptr noundef nonnull align 8 dereferenceable(8), ptr noundef nonnull align 8 dereferenceable(8)) local_unnamed_addr #2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 1 dereferenceable(1) ptr @_ZNK9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEdeEv(ptr noundef nonnull align 8 dereferenceable(8)) local_unnamed_addr #1 align 2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local void @_Z6ch_minIcEvRT_S0_(ptr noundef nonnull align 1 dereferenceable(1), i8 noundef signext) local_unnamed_addr #1

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 8 dereferenceable(8) ptr @_ZN9__gnu_cxx17__normal_iteratorIPKcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEppEv(ptr noundef nonnull align 8 dereferenceable(8)) local_unnamed_addr #1 align 2

attributes #0 = { mustprogress 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 = { inlinehint 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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C++ TBAA"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass