; LLVM IR from next-step-for-interview-prep/Coding-Ninjas-DSA-course_code_and_notes_cpp :: Milestone-2=Intro_to_C++/questions and solutions/Lec-10=Character-arrays_and_2D-arra_84b933b9 (Z26removeAllOccurrencesOfCharPcc)

; 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: mustprogress nounwind uwtable
define dso_local void @_Z26removeAllOccurrencesOfCharPcc(ptr noundef %0, i8 noundef signext %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca i8, align 1
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  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 4, ptr %5) #4
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  %9 = call i64 @strlen(ptr noundef %8) #5
  %10 = trunc i64 %9 to i32
  store i32 %10, ptr %5, align 4, !tbaa !10
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #4
  store i32 0, ptr %6, align 4, !tbaa !10
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #4
  store i32 0, ptr %7, align 4, !tbaa !10
  br label %11

11:                                               ; preds = %37, %2
  %12 = load i32, ptr %7, align 4, !tbaa !10
  %13 = load i32, ptr %5, align 4, !tbaa !10
  %14 = icmp slt i32 %12, %13
  br i1 %14, label %16, label %15

15:                                               ; preds = %11
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #4
  br label %40

16:                                               ; preds = %11
  %17 = load ptr, ptr %3, align 8, !tbaa !5
  %18 = load i32, ptr %7, align 4, !tbaa !10
  %19 = sext i32 %18 to i64
  %20 = getelementptr inbounds i8, ptr %17, i64 %19
  %21 = load i8, ptr %20, align 1, !tbaa !9
  %22 = sext i8 %21 to i32
  %23 = load i8, ptr %4, align 1, !tbaa !9
  %24 = sext i8 %23 to i32
  %25 = icmp ne i32 %22, %24
  br i1 %25, label %26, label %36

26:                                               ; preds = %16
  %27 = load ptr, ptr %3, align 8, !tbaa !5
  %28 = load i32, ptr %7, align 4, !tbaa !10
  %29 = sext i32 %28 to i64
  %30 = getelementptr inbounds i8, ptr %27, i64 %29
  %31 = load ptr, ptr %3, align 8, !tbaa !5
  %32 = load i32, ptr %6, align 4, !tbaa !10
  %33 = add nsw i32 %32, 1
  store i32 %33, ptr %6, align 4, !tbaa !10
  %34 = sext i32 %32 to i64
  %35 = getelementptr inbounds i8, ptr %31, i64 %34
  call void @_ZSt4swapIcENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 1 dereferenceable(1) %30, ptr noundef nonnull align 1 dereferenceable(1) %35) #4
  br label %36

36:                                               ; preds = %26, %16
  br label %37

37:                                               ; preds = %36
  %38 = load i32, ptr %7, align 4, !tbaa !10
  %39 = add nsw i32 %38, 1
  store i32 %39, ptr %7, align 4, !tbaa !10
  br label %11, !llvm.loop !12

40:                                               ; preds = %15
  %41 = load ptr, ptr %3, align 8, !tbaa !5
  %42 = load i32, ptr %6, align 4, !tbaa !10
  %43 = sext i32 %42 to i64
  %44 = getelementptr inbounds i8, ptr %41, i64 %43
  store i8 0, ptr %44, align 1, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #4
  ret void
}

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

; Function Attrs: nounwind willreturn memory(read)
declare i64 @strlen(ptr noundef) #2

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local void @_ZSt4swapIcENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 1 dereferenceable(1), ptr noundef nonnull align 1 dereferenceable(1)) #3

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

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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { nounwind willreturn memory(read) "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 = { inlinehint 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 #4 = { nounwind }
attributes #5 = { nounwind willreturn memory(read) }

!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 = !{!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 nounwind uwtable
define dso_local void @_Z26removeAllOccurrencesOfCharPcc(ptr noundef %0, i8 noundef signext %1) local_unnamed_addr #0 {
  %3 = tail call i64 @strlen(ptr noundef nonnull dereferenceable(1) %0) #3
  %4 = trunc i64 %3 to i32
  %5 = icmp sgt i32 %4, 0
  br i1 %5, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %2
  %wide.trip.count = and i64 %3, 2147483647
  br label %.lr.ph

._crit_edge.loopexit:                             ; preds = %14
  %6 = sext i32 %.1 to i64
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %2
  %.012.lcssa = phi i64 [ 0, %2 ], [ %6, %._crit_edge.loopexit ]
  %7 = getelementptr inbounds i8, ptr %0, i64 %.012.lcssa
  store i8 0, ptr %7, align 1, !tbaa !5
  ret void

.lr.ph:                                           ; preds = %.lr.ph.preheader, %14
  %indvars.iv = phi i64 [ 0, %.lr.ph.preheader ], [ %indvars.iv.next, %14 ]
  %.01213 = phi i32 [ 0, %.lr.ph.preheader ], [ %.1, %14 ]
  %8 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv
  %9 = load i8, ptr %8, align 1, !tbaa !5
  %.not = icmp eq i8 %9, %1
  br i1 %.not, label %14, label %10

10:                                               ; preds = %.lr.ph
  %11 = add nsw i32 %.01213, 1
  %12 = sext i32 %.01213 to i64
  %13 = getelementptr inbounds i8, ptr %0, i64 %12
  tail call void @_ZSt4swapIcENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 1 dereferenceable(1) %8, ptr noundef nonnull align 1 dereferenceable(1) %13) #4
  br label %14

14:                                               ; preds = %.lr.ph, %10
  %.1 = phi i32 [ %11, %10 ], [ %.01213, %.lr.ph ]
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %exitcond.not = icmp eq i64 %indvars.iv.next, %wide.trip.count
  br i1 %exitcond.not, label %._crit_edge.loopexit, label %.lr.ph, !llvm.loop !8
}

; Function Attrs: mustprogress nofree nounwind willreturn memory(argmem: read)
declare i64 @strlen(ptr nocapture noundef) local_unnamed_addr #1

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local void @_ZSt4swapIcENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 1 dereferenceable(1), ptr noundef nonnull align 1 dereferenceable(1)) local_unnamed_addr #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 nofree nounwind willreturn memory(argmem: read) "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 = { inlinehint 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 #3 = { nounwind willreturn memory(read) }
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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C++ TBAA"}
!8 = distinct !{!8, !9}
!9 = !{!"llvm.loop.mustprogress"}


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