; LLVM IR from chachaxw/data-structure-and-algorithm :: leetcode/two_pointers (reverse_words_in_a_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 uwtable
define dso_local void @_ZN8Solution7reverseERNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEii(ptr noundef nonnull align 1 dereferenceable(1) %0, ptr noundef nonnull align 8 dereferenceable(32) %1, i32 noundef %2, i32 noundef %3) #0 align 2 {
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  %9 = alloca i32, align 4
  %10 = alloca i32, align 4
  store ptr %0, ptr %5, align 8, !tbaa !5
  store ptr %1, ptr %6, align 8, !tbaa !5
  store i32 %2, ptr %7, align 4, !tbaa !9
  store i32 %3, ptr %8, align 4, !tbaa !9
  %11 = load ptr, ptr %5, align 8
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #4
  %12 = load i32, ptr %7, align 4, !tbaa !9
  store i32 %12, ptr %9, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %10) #4
  %13 = load i32, ptr %8, align 4, !tbaa !9
  store i32 %13, ptr %10, align 4, !tbaa !9
  br label %14

14:                                               ; preds = %28, %4
  %15 = load i32, ptr %9, align 4, !tbaa !9
  %16 = load i32, ptr %10, align 4, !tbaa !9
  %17 = icmp slt i32 %15, %16
  br i1 %17, label %19, label %18

18:                                               ; preds = %14
  call void @llvm.lifetime.end.p0(i64 4, ptr %10) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #4
  br label %33

19:                                               ; preds = %14
  %20 = load ptr, ptr %6, align 8, !tbaa !5
  %21 = load i32, ptr %9, align 4, !tbaa !9
  %22 = sext i32 %21 to i64
  %23 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %20, i64 noundef %22)
  %24 = load ptr, ptr %6, align 8, !tbaa !5
  %25 = load i32, ptr %10, align 4, !tbaa !9
  %26 = sext i32 %25 to i64
  %27 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %24, i64 noundef %26)
  call void @_ZSt4swapIcENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 1 dereferenceable(1) %23, ptr noundef nonnull align 1 dereferenceable(1) %27) #4
  br label %28

28:                                               ; preds = %19
  %29 = load i32, ptr %9, align 4, !tbaa !9
  %30 = add nsw i32 %29, 1
  store i32 %30, ptr %9, align 4, !tbaa !9
  %31 = load i32, ptr %10, align 4, !tbaa !9
  %32 = add nsw i32 %31, -1
  store i32 %32, ptr %10, align 4, !tbaa !9
  br label %14, !llvm.loop !11

33:                                               ; preds = %18
  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 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

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local void @_ZSt4swapIcENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 1 dereferenceable(1), ptr noundef nonnull align 1 dereferenceable(1)) #3

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 = { 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 = !{!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 @_ZN8Solution7reverseERNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEii(ptr nocapture noundef nonnull readnone align 1 dereferenceable(1) %0, ptr noundef nonnull align 8 dereferenceable(32) %1, i32 noundef %2, i32 noundef %3) local_unnamed_addr #0 align 2 {
  %5 = icmp slt i32 %2, %3
  br i1 %5, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %4
  %6 = sext i32 %3 to i64
  %7 = sext i32 %2 to i64
  br label %.lr.ph

._crit_edge:                                      ; preds = %.lr.ph, %4
  ret void

.lr.ph:                                           ; preds = %.lr.ph.preheader, %.lr.ph
  %indvars.iv13 = phi i64 [ %7, %.lr.ph.preheader ], [ %indvars.iv.next14, %.lr.ph ]
  %indvars.iv = phi i64 [ %6, %.lr.ph.preheader ], [ %indvars.iv.next, %.lr.ph ]
  %8 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %1, i64 noundef %indvars.iv13)
  %9 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %1, i64 noundef %indvars.iv)
  tail call void @_ZSt4swapIcENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 1 dereferenceable(1) %8, ptr noundef nonnull align 1 dereferenceable(1) %9) #2
  %indvars.iv.next14 = add nsw i64 %indvars.iv13, 1
  %indvars.iv.next = add nsw i64 %indvars.iv, -1
  %10 = icmp slt i64 %indvars.iv.next14, %indvars.iv.next
  br i1 %10, label %.lr.ph, label %._crit_edge, !llvm.loop !5
}

; 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

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local void @_ZSt4swapIcENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 1 dereferenceable(1), ptr noundef nonnull align 1 dereferenceable(1)) local_unnamed_addr #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 = { 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: GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,JumpThreadingPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass