; LLVM IR from eyangch/competitive-programming :: USACOcontests/platinum/2020.02/triangles.ll (Z4flipv)

; 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.std::__cxx11::basic_string" = type { %"struct.std::__cxx11::basic_string<char>::_Alloc_hider", i64, %union.anon }
%"struct.std::__cxx11::basic_string<char>::_Alloc_hider" = type { ptr }
%union.anon = type { i64, [8 x i8] }
%"class.__gnu_cxx::__normal_iterator" = type { ptr }

@N = external dso_local global i64, align 8
@_Z1SB5cxx11 = external dso_local global [300 x %"class.std::__cxx11::basic_string"], align 16

; Function Attrs: mustprogress uwtable
define dso_local void @_Z4flipv() #0 {
  %1 = alloca i64, align 8
  %2 = alloca %"class.__gnu_cxx::__normal_iterator", align 8
  %3 = alloca %"class.__gnu_cxx::__normal_iterator", align 8
  call void @llvm.lifetime.start.p0(i64 8, ptr %1) #4
  store i64 0, ptr %1, align 8, !tbaa !5
  br label %4

4:                                                ; preds = %22, %0
  %5 = load i64, ptr %1, align 8, !tbaa !5
  %6 = load i64, ptr @N, align 8, !tbaa !5
  %7 = icmp slt i64 %5, %6
  br i1 %7, label %9, label %8

8:                                                ; preds = %4
  call void @llvm.lifetime.end.p0(i64 8, ptr %1) #4
  br label %25

9:                                                ; preds = %4
  %10 = load i64, ptr %1, align 8, !tbaa !5
  %11 = getelementptr inbounds [300 x %"class.std::__cxx11::basic_string"], ptr @_Z1SB5cxx11, i64 0, i64 %10
  %12 = call ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE5beginEv(ptr noundef nonnull align 8 dereferenceable(32) %11) #4
  %13 = getelementptr inbounds %"class.__gnu_cxx::__normal_iterator", ptr %2, i32 0, i32 0
  store ptr %12, ptr %13, align 8
  %14 = load i64, ptr %1, align 8, !tbaa !5
  %15 = getelementptr inbounds [300 x %"class.std::__cxx11::basic_string"], ptr @_Z1SB5cxx11, i64 0, i64 %14
  %16 = call ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE3endEv(ptr noundef nonnull align 8 dereferenceable(32) %15) #4
  %17 = getelementptr inbounds %"class.__gnu_cxx::__normal_iterator", ptr %3, i32 0, i32 0
  store ptr %16, ptr %17, align 8
  %18 = getelementptr inbounds %"class.__gnu_cxx::__normal_iterator", ptr %2, i32 0, i32 0
  %19 = load ptr, ptr %18, align 8
  %20 = getelementptr inbounds %"class.__gnu_cxx::__normal_iterator", ptr %3, i32 0, i32 0
  %21 = load ptr, ptr %20, align 8
  call void @_ZSt7reverseIN9__gnu_cxx17__normal_iteratorIPcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEEvT_SA_(ptr %19, ptr %21)
  br label %22

22:                                               ; preds = %9
  %23 = load i64, ptr %1, align 8, !tbaa !5
  %24 = add nsw i64 %23, 1
  store i64 %24, ptr %1, align 8, !tbaa !5
  br label %4, !llvm.loop !9

25:                                               ; preds = %8
  ret void
}

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

; Function Attrs: inlinehint mustprogress uwtable
declare dso_local void @_ZSt7reverseIN9__gnu_cxx17__normal_iteratorIPcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEEvT_SA_(ptr, ptr) #2

; Function Attrs: mustprogress nounwind uwtable
declare ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE5beginEv(ptr noundef nonnull align 8 dereferenceable(32)) #3 align 2

; Function Attrs: mustprogress nounwind uwtable
declare ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE3endEv(ptr noundef nonnull align 8 dereferenceable(32)) #3 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 = { inlinehint 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 #3 = { 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 = !{!"long long", !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"

%"class.std::__cxx11::basic_string" = type { %"struct.std::__cxx11::basic_string<char>::_Alloc_hider", i64, %union.anon }
%"struct.std::__cxx11::basic_string<char>::_Alloc_hider" = type { ptr }
%union.anon = type { i64, [8 x i8] }

@N = external dso_local local_unnamed_addr global i64, align 8
@_Z1SB5cxx11 = external dso_local global [300 x %"class.std::__cxx11::basic_string"], align 16

; Function Attrs: mustprogress uwtable
define dso_local void @_Z4flipv() local_unnamed_addr #0 {
  %1 = load i64, ptr @N, align 8, !tbaa !5
  %2 = icmp sgt i64 %1, 0
  br i1 %2, label %.lr.ph, label %._crit_edge

._crit_edge:                                      ; preds = %.lr.ph, %0
  ret void

.lr.ph:                                           ; preds = %0, %.lr.ph
  %.05 = phi i64 [ %6, %.lr.ph ], [ 0, %0 ]
  %3 = getelementptr inbounds [300 x %"class.std::__cxx11::basic_string"], ptr @_Z1SB5cxx11, i64 0, i64 %.05
  %4 = tail call ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE5beginEv(ptr noundef nonnull align 8 dereferenceable(32) %3) #3
  %5 = tail call ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE3endEv(ptr noundef nonnull align 8 dereferenceable(32) %3) #3
  tail call void @_ZSt7reverseIN9__gnu_cxx17__normal_iteratorIPcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEEvT_SA_(ptr %4, ptr %5)
  %6 = add nuw nsw i64 %.05, 1
  %7 = load i64, ptr @N, align 8, !tbaa !5
  %8 = icmp slt i64 %6, %7
  br i1 %8, label %.lr.ph, label %._crit_edge, !llvm.loop !9
}

; Function Attrs: inlinehint mustprogress uwtable
declare dso_local void @_ZSt7reverseIN9__gnu_cxx17__normal_iteratorIPcNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEEEvT_SA_(ptr, ptr) local_unnamed_addr #1

; Function Attrs: mustprogress nounwind uwtable
declare ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE5beginEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE3endEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #2 align 2

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 = { inlinehint 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 = { 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 = !{!"long long", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}


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