; LLVM IR from chachaxw/data-structure-and-algorithm :: leetcode/two_pointers (reverse_string)

; 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 nounwind uwtable
define dso_local void @_ZN8Solution13reverseStringERSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS6_EE(ptr noundef nonnull align 1 dereferenceable(1) %0, ptr noundef nonnull align 8 dereferenceable(24) %1) #0 align 2 {
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  store ptr %1, ptr %4, align 8, !tbaa !5
  %7 = load ptr, ptr %3, align 8
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  store i32 0, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #3
  %8 = load ptr, ptr %4, align 8, !tbaa !5
  %9 = call noundef i64 @_ZNKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE4sizeEv(ptr noundef nonnull align 8 dereferenceable(24) %8) #3
  %10 = sub i64 %9, 1
  %11 = trunc i64 %10 to i32
  store i32 %11, ptr %6, align 4, !tbaa !9
  br label %12

12:                                               ; preds = %29, %2
  %13 = load i32, ptr %5, align 4, !tbaa !9
  %14 = sext i32 %13 to i64
  %15 = load ptr, ptr %4, align 8, !tbaa !5
  %16 = call noundef i64 @_ZNKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE4sizeEv(ptr noundef nonnull align 8 dereferenceable(24) %15) #3
  %17 = udiv i64 %16, 2
  %18 = icmp ult i64 %14, %17
  br i1 %18, label %20, label %19

19:                                               ; preds = %12
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  br label %34

20:                                               ; preds = %12
  %21 = load ptr, ptr %4, align 8, !tbaa !5
  %22 = load i32, ptr %5, align 4, !tbaa !9
  %23 = sext i32 %22 to i64
  %24 = call noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EEixEm(ptr noundef nonnull align 8 dereferenceable(24) %21, i64 noundef %23) #3
  %25 = load ptr, ptr %4, align 8, !tbaa !5
  %26 = load i32, ptr %6, align 4, !tbaa !9
  %27 = sext i32 %26 to i64
  %28 = call noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EEixEm(ptr noundef nonnull align 8 dereferenceable(24) %25, i64 noundef %27) #3
  call void @_ZSt4swapIcSt11char_traitsIcESaIcEEvRNSt7__cxx1112basic_stringIT_T0_T1_EES9_(ptr noundef nonnull align 8 dereferenceable(32) %24, ptr noundef nonnull align 8 dereferenceable(32) %28) #3
  br label %29

29:                                               ; preds = %20
  %30 = load i32, ptr %5, align 4, !tbaa !9
  %31 = add nsw i32 %30, 1
  store i32 %31, ptr %5, align 4, !tbaa !9
  %32 = load i32, ptr %6, align 4, !tbaa !9
  %33 = add nsw i32 %32, -1
  store i32 %33, ptr %6, align 4, !tbaa !9
  br label %12, !llvm.loop !11

34:                                               ; preds = %19
  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: mustprogress nounwind uwtable
declare dso_local noundef i64 @_ZNKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE4sizeEv(ptr noundef nonnull align 8 dereferenceable(24)) #0 align 2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local void @_ZSt4swapIcSt11char_traitsIcESaIcEEvRNSt7__cxx1112basic_stringIT_T0_T1_EES9_(ptr noundef nonnull align 8 dereferenceable(32), ptr noundef nonnull align 8 dereferenceable(32)) #2

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EEixEm(ptr noundef nonnull align 8 dereferenceable(24), i64 noundef) #0 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 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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 = !{!"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"

; Function Attrs: mustprogress nounwind uwtable
define dso_local void @_ZN8Solution13reverseStringERSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS6_EE(ptr nocapture noundef nonnull readnone align 1 dereferenceable(1) %0, ptr noundef nonnull align 8 dereferenceable(24) %1) local_unnamed_addr #0 align 2 {
  %3 = tail call noundef i64 @_ZNKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE4sizeEv(ptr noundef nonnull align 8 dereferenceable(24) %1) #2
  %4 = tail call noundef i64 @_ZNKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE4sizeEv(ptr noundef nonnull align 8 dereferenceable(24) %1) #2
  %.not = icmp ult i64 %4, 2
  br i1 %.not, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %2
  %5 = trunc i64 %3 to i32
  br label %.lr.ph

._crit_edge:                                      ; preds = %.lr.ph, %2
  ret void

.lr.ph:                                           ; preds = %.lr.ph.preheader, %.lr.ph
  %indvars.iv = phi i64 [ 0, %.lr.ph.preheader ], [ %indvars.iv.next, %.lr.ph ]
  %.0.in12 = phi i32 [ %5, %.lr.ph.preheader ], [ %.0, %.lr.ph ]
  %.0 = add i32 %.0.in12, -1
  %6 = tail call noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EEixEm(ptr noundef nonnull align 8 dereferenceable(24) %1, i64 noundef %indvars.iv) #2
  %7 = sext i32 %.0 to i64
  %8 = tail call noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EEixEm(ptr noundef nonnull align 8 dereferenceable(24) %1, i64 noundef %7) #2
  tail call void @_ZSt4swapIcSt11char_traitsIcESaIcEEvRNSt7__cxx1112basic_stringIT_T0_T1_EES9_(ptr noundef nonnull align 8 dereferenceable(32) %6, ptr noundef nonnull align 8 dereferenceable(32) %8) #2
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %9 = tail call noundef i64 @_ZNKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE4sizeEv(ptr noundef nonnull align 8 dereferenceable(24) %1) #2
  %10 = lshr i64 %9, 1
  %11 = icmp ugt i64 %10, %indvars.iv.next
  br i1 %11, label %.lr.ph, label %._crit_edge, !llvm.loop !5
}

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef i64 @_ZNKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE4sizeEv(ptr noundef nonnull align 8 dereferenceable(24)) local_unnamed_addr #0 align 2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local void @_ZSt4swapIcSt11char_traitsIcESaIcEEvRNSt7__cxx1112basic_stringIT_T0_T1_EES9_(ptr noundef nonnull align 8 dereferenceable(32), ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #1

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EEixEm(ptr noundef nonnull align 8 dereferenceable(24), 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 = { 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 #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 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


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