; LLVM IR from freddiev4/dailyprogrammerchallenges :: Easy Challenges/Challenge 0003 Easy/solutions (solution)

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

; Function Attrs: mustprogress nounwind uwtable
declare void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC2Ev(ptr noundef nonnull align 8 dereferenceable(32)) unnamed_addr #1 align 2

declare i32 @__gxx_personality_v0(...)

; Function Attrs: mustprogress nounwind uwtable
declare void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32)) unnamed_addr #1 align 2

; 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 void @_Z7decryptNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEi(ptr dead_on_unwind noalias writable sret(%"class.std::__cxx11::basic_string") align 8 %0, ptr noundef %1, i32 noundef %2) #2 personality ptr @__gxx_personality_v0 {
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca i32, align 4
  %7 = alloca i1, align 1
  %8 = alloca i64, align 8
  %9 = alloca i8, align 1
  %10 = alloca ptr, align 8
  %11 = alloca i32, align 4
  %12 = alloca i32, align 4
  store ptr %0, ptr %4, align 8
  store ptr %1, ptr %5, align 8, !tbaa !5
  store i32 %2, ptr %6, align 4, !tbaa !9
  store i1 false, ptr %7, align 1
  call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  call void @llvm.lifetime.start.p0(i64 8, ptr %8) #3
  store i64 0, ptr %8, align 8, !tbaa !11
  br label %13

13:                                               ; preds = %47, %3
  %14 = load i64, ptr %8, align 8, !tbaa !11
  %15 = call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(32) %1) #3
  %16 = icmp ult i64 %14, %15
  br i1 %16, label %18, label %17

17:                                               ; preds = %13
  call void @llvm.lifetime.end.p0(i64 8, ptr %8) #3
  br label %50

18:                                               ; preds = %13
  call void @llvm.lifetime.start.p0(i64 1, ptr %9) #3
  %19 = load i64, ptr %8, align 8, !tbaa !11
  %20 = invoke noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %1, i64 noundef %19)
          to label %21 unwind label %39

21:                                               ; preds = %18
  %22 = load i8, ptr %20, align 1, !tbaa !13
  store i8 %22, ptr %9, align 1, !tbaa !13
  %23 = load i8, ptr %9, align 1, !tbaa !13
  %24 = sext i8 %23 to i32
  %25 = load i32, ptr %6, align 4, !tbaa !9
  %26 = sub nsw i32 %24, %25
  %27 = trunc i32 %26 to i8
  store i8 %27, ptr %9, align 1, !tbaa !13
  %28 = load i8, ptr %9, align 1, !tbaa !13
  %29 = sext i8 %28 to i32
  %30 = icmp slt i32 %29, 97
  br i1 %30, label %31, label %43

31:                                               ; preds = %21
  call void @llvm.lifetime.start.p0(i64 4, ptr %12) #3
  %32 = load i8, ptr %9, align 1, !tbaa !13
  %33 = sext i8 %32 to i32
  %34 = sub nsw i32 97, %33
  store i32 %34, ptr %12, align 4, !tbaa !9
  %35 = load i32, ptr %12, align 4, !tbaa !9
  %36 = sub nsw i32 122, %35
  %37 = add nsw i32 %36, 1
  %38 = trunc i32 %37 to i8
  store i8 %38, ptr %9, align 1, !tbaa !13
  call void @llvm.lifetime.end.p0(i64 4, ptr %12) #3
  br label %43

39:                                               ; preds = %43, %18
  %40 = landingpad { ptr, i32 }
          cleanup
  %41 = extractvalue { ptr, i32 } %40, 0
  store ptr %41, ptr %10, align 8
  %42 = extractvalue { ptr, i32 } %40, 1
  store i32 %42, ptr %11, align 4
  call void @llvm.lifetime.end.p0(i64 1, ptr %9) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %8) #3
  call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  br label %54

43:                                               ; preds = %31, %21
  %44 = load i8, ptr %9, align 1, !tbaa !13
  %45 = invoke noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEpLEc(ptr noundef nonnull align 8 dereferenceable(32) %0, i8 noundef signext %44)
          to label %46 unwind label %39

46:                                               ; preds = %43
  call void @llvm.lifetime.end.p0(i64 1, ptr %9) #3
  br label %47

47:                                               ; preds = %46
  %48 = load i64, ptr %8, align 8, !tbaa !11
  %49 = add i64 %48, 1
  store i64 %49, ptr %8, align 8, !tbaa !11
  br label %13, !llvm.loop !14

50:                                               ; preds = %17
  store i1 true, ptr %7, align 1
  %51 = load i1, ptr %7, align 1
  br i1 %51, label %53, label %52

52:                                               ; preds = %50
  call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  br label %53

53:                                               ; preds = %52, %50
  ret void

54:                                               ; preds = %39
  %55 = load ptr, ptr %10, align 8
  %56 = load i32, ptr %11, align 4
  %57 = insertvalue { ptr, i32 } poison, ptr %55, 0
  %58 = insertvalue { ptr, i32 } %57, i32 %56, 1
  resume { ptr, i32 } %58
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(32)) #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) #1 align 2

; Function Attrs: mustprogress uwtable
declare noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEpLEc(ptr noundef nonnull align 8 dereferenceable(32), i8 noundef signext) #2 align 2

attributes #0 = { 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 = { 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 = { 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 = !{!12, !12, i64 0}
!12 = !{!"long", !7, i64 0}
!13 = !{!7, !7, i64 0}
!14 = distinct !{!14, !15}
!15 = !{!"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 nounwind uwtable
declare void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC2Ev(ptr noundef nonnull align 8 dereferenceable(32)) unnamed_addr #0 align 2

declare i32 @__gxx_personality_v0(...)

; Function Attrs: mustprogress nounwind uwtable
declare void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32)) unnamed_addr #0 align 2

; Function Attrs: mustprogress uwtable
define dso_local void @_Z7decryptNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEi(ptr dead_on_unwind noalias nonnull writable sret(%"class.std::__cxx11::basic_string") align 8 %0, ptr noundef %1, i32 noundef %2) local_unnamed_addr #1 personality ptr @__gxx_personality_v0 {
  tail call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #2
  %4 = tail call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(32) %1) #2
  %.not = icmp eq i64 %4, 0
  br i1 %.not, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %3
  %5 = trunc i32 %2 to i8
  br label %6

6:                                                ; preds = %.lr.ph, %15
  %.013 = phi i64 [ 0, %.lr.ph ], [ %16, %15 ]
  %7 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %1, i64 noundef %.013)
  %8 = load i8, ptr %7, align 1, !tbaa !5
  %9 = sub i8 %8, %5
  %10 = icmp slt i8 %9, 97
  %11 = add i8 %9, 26
  %spec.select = select i1 %10, i8 %11, i8 %9
  %12 = invoke noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEpLEc(ptr noundef nonnull align 8 dereferenceable(32) %0, i8 noundef signext %spec.select)
          to label %15 unwind label %13

13:                                               ; preds = %6
  %14 = landingpad { ptr, i32 }
          cleanup
  tail call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #2
  resume { ptr, i32 } %14

15:                                               ; preds = %6
  %16 = add nuw i64 %.013, 1
  %17 = tail call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(32) %1) #2
  %18 = icmp ult i64 %16, %17
  br i1 %18, label %6, label %._crit_edge, !llvm.loop !8

._crit_edge:                                      ; preds = %15, %3
  ret void
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE4sizeEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #0 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 #0 align 2

; Function Attrs: mustprogress uwtable
declare noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEpLEc(ptr noundef nonnull align 8 dereferenceable(32), i8 noundef signext) local_unnamed_addr #1 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 = { 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 = { 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: CorrelatedValuePropagationPass,EarlyCSEPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LICMPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass