; LLVM IR from nonstriater/Learn-Algorithms :: 9 Algorithms Job Interview/codes/1 string (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: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

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

; Function Attrs: nounwind uwtable
define dso_local void @filternum(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  %5 = load ptr, ptr %2, align 8, !tbaa !5
  %6 = load i8, ptr %5, align 1, !tbaa !9
  %7 = icmp ne i8 %6, 0
  br i1 %7, label %9, label %8

8:                                                ; preds = %1
  br label %38

9:                                                ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #2
  %10 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %10, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %11 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %11, ptr %4, align 8, !tbaa !5
  br label %12

12:                                               ; preds = %35, %9
  %13 = load ptr, ptr %4, align 8, !tbaa !5
  %14 = load i8, ptr %13, align 1, !tbaa !9
  %15 = icmp ne i8 %14, 0
  br i1 %15, label %16, label %36

16:                                               ; preds = %12
  %17 = load ptr, ptr %4, align 8, !tbaa !5
  %18 = load i8, ptr %17, align 1, !tbaa !9
  %19 = sext i8 %18 to i32
  %20 = icmp sge i32 %19, 48
  br i1 %20, label %21, label %29

21:                                               ; preds = %16
  %22 = load ptr, ptr %4, align 8, !tbaa !5
  %23 = load i8, ptr %22, align 1, !tbaa !9
  %24 = sext i8 %23 to i32
  %25 = icmp sle i32 %24, 57
  br i1 %25, label %26, label %29

26:                                               ; preds = %21
  %27 = load ptr, ptr %4, align 8, !tbaa !5
  %28 = getelementptr inbounds i8, ptr %27, i32 1
  store ptr %28, ptr %4, align 8, !tbaa !5
  br label %35

29:                                               ; preds = %21, %16
  %30 = load ptr, ptr %4, align 8, !tbaa !5
  %31 = getelementptr inbounds i8, ptr %30, i32 1
  store ptr %31, ptr %4, align 8, !tbaa !5
  %32 = load i8, ptr %30, align 1, !tbaa !9
  %33 = load ptr, ptr %3, align 8, !tbaa !5
  %34 = getelementptr inbounds i8, ptr %33, i32 1
  store ptr %34, ptr %3, align 8, !tbaa !5
  store i8 %32, ptr %33, align 1, !tbaa !9
  br label %35

35:                                               ; preds = %29, %26
  br label %12, !llvm.loop !10

36:                                               ; preds = %12
  %37 = load ptr, ptr %3, align 8, !tbaa !5
  store i8 0, ptr %37, align 1, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #2
  br label %38

38:                                               ; preds = %36, %8
  ret void
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/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"

; Function Attrs: nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local void @filternum(ptr nocapture noundef %0) local_unnamed_addr #0 {
  %2 = load i8, ptr %0, align 1, !tbaa !5
  %.not = icmp eq i8 %2, 0
  br i1 %.not, label %9, label %.preheader

.preheader:                                       ; preds = %1, %7
  %.016 = phi ptr [ %.1, %7 ], [ %0, %1 ]
  %.01015 = phi ptr [ %.111, %7 ], [ %0, %1 ]
  %3 = phi i8 [ %.pr, %7 ], [ %2, %1 ]
  %4 = add i8 %3, -48
  %or.cond = icmp ult i8 %4, 10
  br i1 %or.cond, label %7, label %5

5:                                                ; preds = %.preheader
  %6 = getelementptr inbounds i8, ptr %.01015, i64 1
  store i8 %3, ptr %.01015, align 1, !tbaa !5
  br label %7

7:                                                ; preds = %.preheader, %5
  %.111 = phi ptr [ %6, %5 ], [ %.01015, %.preheader ]
  %.1 = getelementptr inbounds i8, ptr %.016, i64 1
  %.pr = load i8, ptr %.1, align 1, !tbaa !5
  %.not14 = icmp eq i8 %.pr, 0
  br i1 %.not14, label %8, label %.preheader, !llvm.loop !8

8:                                                ; preds = %7
  store i8 0, ptr %.111, align 1, !tbaa !5
  br label %9

9:                                                ; preds = %1, %8
  ret void
}

attributes #0 = { nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) 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" }

!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/C++ TBAA"}
!8 = distinct !{!8, !9}
!9 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass