; LLVM IR from freddiev4/dailyprogrammerchallenges :: Easy Challenges/Challenge 0004 Easy/solutions/solution.ll (Z18password_generatorB5cxx11i)

; 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 @_Z18password_generatorB5cxx11i(ptr dead_on_unwind noalias writable sret(%"class.std::__cxx11::basic_string") align 8 %0, i32 noundef %1) #0 personality ptr @__gxx_personality_v0 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca i1, align 1
  %6 = alloca i32, align 4
  %7 = alloca i8, align 1
  %8 = alloca ptr, align 8
  %9 = alloca i32, align 4
  store ptr %0, ptr %3, align 8
  store i32 %1, ptr %4, align 4, !tbaa !5
  store i1 false, ptr %5, align 1
  call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #4
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #4
  store i32 0, ptr %6, align 4, !tbaa !5
  br label %10

10:                                               ; preds = %23, %2
  %11 = load i32, ptr %6, align 4, !tbaa !5
  %12 = load i32, ptr %4, align 4, !tbaa !5
  %13 = icmp slt i32 %11, %12
  br i1 %13, label %15, label %14

14:                                               ; preds = %10
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #4
  br label %30

15:                                               ; preds = %10
  call void @llvm.lifetime.start.p0(i64 1, ptr %7) #4
  %16 = call i32 @rand() #4
  %17 = srem i32 %16, 26
  %18 = add nsw i32 %17, 97
  %19 = trunc i32 %18 to i8
  store i8 %19, ptr %7, align 1, !tbaa !9
  %20 = load i8, ptr %7, align 1, !tbaa !9
  %21 = invoke noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEpLEc(ptr noundef nonnull align 8 dereferenceable(32) %0, i8 noundef signext %20)
          to label %22 unwind label %26

22:                                               ; preds = %15
  call void @llvm.lifetime.end.p0(i64 1, ptr %7) #4
  br label %23

23:                                               ; preds = %22
  %24 = load i32, ptr %6, align 4, !tbaa !5
  %25 = add nsw i32 %24, 1
  store i32 %25, ptr %6, align 4, !tbaa !5
  br label %10, !llvm.loop !10

26:                                               ; preds = %15
  %27 = landingpad { ptr, i32 }
          cleanup
  %28 = extractvalue { ptr, i32 } %27, 0
  store ptr %28, ptr %8, align 8
  %29 = extractvalue { ptr, i32 } %27, 1
  store i32 %29, ptr %9, align 4
  call void @llvm.lifetime.end.p0(i64 1, ptr %7) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #4
  call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #4
  br label %34

30:                                               ; preds = %14
  store i1 true, ptr %5, align 1
  %31 = load i1, ptr %5, align 1
  br i1 %31, label %33, label %32

32:                                               ; preds = %30
  call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #4
  br label %33

33:                                               ; preds = %32, %30
  ret void

34:                                               ; preds = %26
  %35 = load ptr, ptr %8, align 8
  %36 = load i32, ptr %9, align 4
  %37 = insertvalue { ptr, i32 } poison, ptr %35, 0
  %38 = insertvalue { ptr, i32 } %37, i32 %36, 1
  resume { ptr, i32 } %38
}

; Function Attrs: mustprogress nounwind uwtable
declare void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC2Ev(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.start.p0(i64 immarg, ptr nocapture) #2

; Function Attrs: nounwind
declare i32 @rand() #3

; 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) #0 align 2

declare i32 @__gxx_personality_v0(...)

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #2

; Function Attrs: mustprogress nounwind uwtable
declare void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32)) unnamed_addr #1 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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #3 = { nounwind "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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!7, !7, i64 0}
!10 = distinct !{!10, !11}
!11 = !{!"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 @_Z18password_generatorB5cxx11i(ptr dead_on_unwind noalias nonnull writable sret(%"class.std::__cxx11::basic_string") align 8 %0, i32 noundef %1) local_unnamed_addr #0 personality ptr @__gxx_personality_v0 {
  tail call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  %3 = icmp sgt i32 %1, 0
  br i1 %3, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %2, %9
  %.06 = phi i32 [ %10, %9 ], [ 0, %2 ]
  %4 = tail call i32 @rand() #3
  %5 = srem i32 %4, 26
  %6 = trunc nsw i32 %5 to i8
  %7 = add nsw i8 %6, 97
  %8 = invoke noundef nonnull align 8 dereferenceable(32) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEpLEc(ptr noundef nonnull align 8 dereferenceable(32) %0, i8 noundef signext %7)
          to label %9 unwind label %11

9:                                                ; preds = %.lr.ph
  %10 = add nuw nsw i32 %.06, 1
  %exitcond.not = icmp eq i32 %10, %1
  br i1 %exitcond.not, label %._crit_edge, label %.lr.ph, !llvm.loop !5

11:                                               ; preds = %.lr.ph
  %12 = landingpad { ptr, i32 }
          cleanup
  tail call void @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  resume { ptr, i32 } %12

._crit_edge:                                      ; preds = %9, %2
  ret void
}

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

; Function Attrs: nounwind
declare i32 @rand() local_unnamed_addr #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 #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 #1 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 "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 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


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