; LLVM IR from nonstriater/Learn-Algorithms :: 9 Algorithms Job Interview/codes/5 array (delete_occurence_character)

; 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: nounwind uwtable
define dso_local ptr @delete_occurence_character(ptr noundef %0, i8 noundef signext %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca i8, align 1
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i8 %1, ptr %4, align 1, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %7, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %8, ptr %6, align 8, !tbaa !5
  br label %9

9:                                                ; preds = %27, %2
  %10 = load ptr, ptr %5, align 8, !tbaa !5
  %11 = load i8, ptr %10, align 1, !tbaa !9
  %12 = sext i8 %11 to i32
  %13 = icmp ne i32 %12, 0
  br i1 %13, label %14, label %30

14:                                               ; preds = %9
  %15 = load ptr, ptr %5, align 8, !tbaa !5
  %16 = load i8, ptr %15, align 1, !tbaa !9
  %17 = sext i8 %16 to i32
  %18 = load i8, ptr %4, align 1, !tbaa !9
  %19 = sext i8 %18 to i32
  %20 = icmp ne i32 %17, %19
  br i1 %20, label %21, label %27

21:                                               ; preds = %14
  %22 = load ptr, ptr %5, align 8, !tbaa !5
  %23 = load i8, ptr %22, align 1, !tbaa !9
  %24 = load ptr, ptr %6, align 8, !tbaa !5
  store i8 %23, ptr %24, align 1, !tbaa !9
  %25 = load ptr, ptr %6, align 8, !tbaa !5
  %26 = getelementptr inbounds i8, ptr %25, i32 1
  store ptr %26, ptr %6, align 8, !tbaa !5
  br label %27

27:                                               ; preds = %21, %14
  %28 = load ptr, ptr %5, align 8, !tbaa !5
  %29 = getelementptr inbounds i8, ptr %28, i32 1
  store ptr %29, ptr %5, align 8, !tbaa !5
  br label %9, !llvm.loop !10

30:                                               ; preds = %9
  %31 = load ptr, ptr %6, align 8, !tbaa !5
  store i8 0, ptr %31, align 1, !tbaa !9
  %32 = load ptr, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  ret ptr %32
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

attributes #0 = { 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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 noundef ptr @delete_occurence_character(ptr noundef returned %0, i8 noundef signext %1) local_unnamed_addr #0 {
  %3 = load i8, ptr %0, align 1, !tbaa !5
  %.not13 = icmp eq i8 %3, 0
  br i1 %.not13, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %2, %7
  %4 = phi i8 [ %9, %7 ], [ %3, %2 ]
  %.015 = phi ptr [ %.1, %7 ], [ %0, %2 ]
  %.01014 = phi ptr [ %8, %7 ], [ %0, %2 ]
  %.not12 = icmp eq i8 %4, %1
  br i1 %.not12, label %7, label %5

5:                                                ; preds = %.lr.ph
  store i8 %4, ptr %.015, align 1, !tbaa !5
  %6 = getelementptr inbounds i8, ptr %.015, i64 1
  br label %7

7:                                                ; preds = %5, %.lr.ph
  %.1 = phi ptr [ %6, %5 ], [ %.015, %.lr.ph ]
  %8 = getelementptr inbounds i8, ptr %.01014, i64 1
  %9 = load i8, ptr %8, align 1, !tbaa !5
  %.not = icmp eq i8 %9, 0
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !8

._crit_edge:                                      ; preds = %7, %2
  %.0.lcssa = phi ptr [ %0, %2 ], [ %.1, %7 ]
  store i8 0, ptr %.0.lcssa, align 1, !tbaa !5
  ret ptr %0
}

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