; 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 @compress(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  %6 = load ptr, ptr %2, align 8, !tbaa !5
  %7 = load i8, ptr %6, align 1, !tbaa !9
  %8 = sext i8 %7 to i64
  %9 = inttoptr i64 %8 to ptr
  %10 = icmp eq ptr %9, null
  br i1 %10, label %11, label %12

11:                                               ; preds = %1
  br label %47

12:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  store i32 1, ptr %3, align 4, !tbaa !10
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %13 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %13, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %14 = load ptr, ptr %2, align 8, !tbaa !5
  %15 = getelementptr inbounds i8, ptr %14, i64 1
  store ptr %15, ptr %5, align 8, !tbaa !5
  br label %16

16:                                               ; preds = %43, %12
  %17 = load ptr, ptr %5, align 8, !tbaa !5
  %18 = load i8, ptr %17, align 1, !tbaa !9
  %19 = icmp ne i8 %18, 0
  br i1 %19, label %20, label %44

20:                                               ; preds = %16
  store i32 1, ptr %3, align 4, !tbaa !10
  %21 = load ptr, ptr %5, align 8, !tbaa !5
  %22 = load i8, ptr %21, align 1, !tbaa !9
  %23 = sext i8 %22 to i32
  %24 = load ptr, ptr %4, align 8, !tbaa !5
  %25 = load i8, ptr %24, align 1, !tbaa !9
  %26 = sext i8 %25 to i32
  %27 = icmp eq i32 %23, %26
  br i1 %27, label %28, label %33

28:                                               ; preds = %20
  %29 = load i32, ptr %3, align 4, !tbaa !10
  %30 = add nsw i32 %29, 1
  store i32 %30, ptr %3, align 4, !tbaa !10
  %31 = load ptr, ptr %5, align 8, !tbaa !5
  %32 = getelementptr inbounds i8, ptr %31, i32 1
  store ptr %32, ptr %5, align 8, !tbaa !5
  br label %43

33:                                               ; preds = %20
  %34 = load i32, ptr %3, align 4, !tbaa !10
  %35 = icmp ne i32 %34, 1
  br i1 %35, label %36, label %42

36:                                               ; preds = %33
  %37 = load ptr, ptr %4, align 8, !tbaa !5
  %38 = getelementptr inbounds i8, ptr %37, i32 1
  store ptr %38, ptr %4, align 8, !tbaa !5
  %39 = load i32, ptr %3, align 4, !tbaa !10
  %40 = trunc i32 %39 to i8
  %41 = load ptr, ptr %4, align 8, !tbaa !5
  store i8 %40, ptr %41, align 1, !tbaa !9
  br label %42

42:                                               ; preds = %36, %33
  br label %43

43:                                               ; preds = %42, %28
  br label %16, !llvm.loop !12

44:                                               ; preds = %16
  %45 = load ptr, ptr %4, align 8, !tbaa !5
  %46 = getelementptr inbounds i8, ptr %45, i32 1
  store ptr %46, ptr %4, align 8, !tbaa !5
  store i8 0, ptr %46, align 1, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  br label %47

47:                                               ; preds = %44, %11
  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 = !{!11, !11, i64 0}
!11 = !{!"int", !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"

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) uwtable
define dso_local void @compress(ptr nocapture noundef %0) local_unnamed_addr #0 {
  %2 = load i8, ptr %0, align 1, !tbaa !5
  %3 = icmp eq i8 %2, 0
  br i1 %3, label %5, label %._crit_edge

._crit_edge:                                      ; preds = %1
  %4 = getelementptr inbounds i8, ptr %0, i64 1
  store i8 0, ptr %4, align 1, !tbaa !5
  br label %5

5:                                                ; preds = %1, %._crit_edge
  ret void
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite) 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"}


; Effective O3 passes: ADCEPass,EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LoopRotatePass,LoopSimplifyPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass