; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 03. Recursion (LongestCommonPrefix (LCP))

; 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] }

; Function Attrs: mustprogress uwtable
define dso_local void @_Z3LCPNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES4_(ptr dead_on_unwind noalias writable sret(%"class.std::__cxx11::basic_string") align 8 %0, ptr noundef %1, ptr noundef %2) #0 {
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  store ptr %0, ptr %4, align 8
  store ptr %1, ptr %5, align 8, !tbaa !5
  store ptr %2, ptr %6, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #3
  store i32 0, ptr %7, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #3
  store i32 0, ptr %8, align 4, !tbaa !9
  br label %9

9:                                                ; preds = %34, %3
  %10 = load i32, ptr %7, align 4, !tbaa !9
  %11 = sext i32 %10 to i64
  %12 = call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %1) #3
  %13 = icmp ult i64 %11, %12
  br i1 %13, label %14, label %19

14:                                               ; preds = %9
  %15 = load i32, ptr %8, align 4, !tbaa !9
  %16 = sext i32 %15 to i64
  %17 = call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %2) #3
  %18 = icmp ult i64 %16, %17
  br label %19

19:                                               ; preds = %14, %9
  %20 = phi i1 [ false, %9 ], [ %18, %14 ]
  br i1 %20, label %21, label %39

21:                                               ; preds = %19
  %22 = load i32, ptr %7, align 4, !tbaa !9
  %23 = sext i32 %22 to i64
  %24 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %1, i64 noundef %23)
  %25 = load i8, ptr %24, align 1, !tbaa !11
  %26 = sext i8 %25 to i32
  %27 = load i32, ptr %8, align 4, !tbaa !9
  %28 = sext i32 %27 to i64
  %29 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %2, i64 noundef %28)
  %30 = load i8, ptr %29, align 1, !tbaa !11
  %31 = sext i8 %30 to i32
  %32 = icmp ne i32 %26, %31
  br i1 %32, label %33, label %34

33:                                               ; preds = %21
  br label %39

34:                                               ; preds = %21
  %35 = load i32, ptr %7, align 4, !tbaa !9
  %36 = add nsw i32 %35, 1
  store i32 %36, ptr %7, align 4, !tbaa !9
  %37 = load i32, ptr %8, align 4, !tbaa !9
  %38 = add nsw i32 %37, 1
  store i32 %38, ptr %8, align 4, !tbaa !9
  br label %9, !llvm.loop !12

39:                                               ; preds = %33, %19
  %40 = load i32, ptr %7, align 4, !tbaa !9
  %41 = sext i32 %40 to i64
  call void @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6substrEmm(ptr dead_on_unwind writable sret(%"class.std::__cxx11::basic_string") align 8 %0, ptr noundef nonnull align 8 dereferenceable(32) %1, i64 noundef 0, i64 noundef %41)
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #3
  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 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: mustprogress uwtable
declare void @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6substrEmm(ptr dead_on_unwind noalias writable sret(%"class.std::__cxx11::basic_string") align 8, ptr noundef nonnull align 8 dereferenceable(32), i64 noundef, 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 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 = !{!"int", !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"

%"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] }

; Function Attrs: mustprogress uwtable
define dso_local void @_Z3LCPNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES4_(ptr dead_on_unwind noalias writable sret(%"class.std::__cxx11::basic_string") align 8 %0, ptr noundef nonnull %1, ptr noundef %2) local_unnamed_addr #0 {
  %4 = tail call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %1) #2
  %.not16 = icmp eq i64 %4, 0
  br i1 %.not16, label %.critedge, label %.lr.ph

.lr.ph:                                           ; preds = %3, %12
  %indvars.iv = phi i64 [ %indvars.iv.next, %12 ], [ 0, %3 ]
  %5 = tail call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %2) #2
  %6 = icmp ugt i64 %5, %indvars.iv
  br i1 %6, label %7, label %.critedge

7:                                                ; preds = %.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.iv)
  %9 = load i8, ptr %8, align 1, !tbaa !5
  %10 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %2, i64 noundef %indvars.iv)
  %11 = load i8, ptr %10, align 1, !tbaa !5
  %.not = icmp eq i8 %9, %11
  br i1 %.not, label %12, label %.critedge

12:                                               ; preds = %7
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %13 = tail call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %1) #2
  %14 = icmp ugt i64 %13, %indvars.iv.next
  br i1 %14, label %.lr.ph, label %.critedge, !llvm.loop !8

.critedge:                                        ; preds = %.lr.ph, %7, %12, %3
  %.lcssa = phi i64 [ 0, %3 ], [ %indvars.iv.next, %12 ], [ %indvars.iv, %7 ], [ %indvars.iv, %.lr.ph ]
  tail call void @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6substrEmm(ptr dead_on_unwind writable sret(%"class.std::__cxx11::basic_string") align 8 %0, ptr noundef nonnull align 8 dereferenceable(32) %1, i64 noundef 0, i64 noundef %.lcssa)
  ret void
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #1 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 #1 align 2

; Function Attrs: mustprogress uwtable
declare void @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6substrEmm(ptr dead_on_unwind noalias writable sret(%"class.std::__cxx11::basic_string") align 8, ptr noundef nonnull align 8 dereferenceable(32), i64 noundef, i64 noundef) local_unnamed_addr #0 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 = { 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 = !{!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: EarlyCSEPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass