; 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 @delete_character(ptr noundef %0, i8 noundef signext %1) #1 {
  %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 = %29, %2
  %10 = load ptr, ptr %6, align 8, !tbaa !5
  %11 = load i8, ptr %10, align 1, !tbaa !9
  %12 = icmp ne i8 %11, 0
  br i1 %12, label %13, label %30

13:                                               ; preds = %9
  %14 = load ptr, ptr %6, align 8, !tbaa !5
  %15 = load i8, ptr %14, align 1, !tbaa !9
  %16 = sext i8 %15 to i32
  %17 = load i8, ptr %4, align 1, !tbaa !9
  %18 = sext i8 %17 to i32
  %19 = icmp eq i32 %16, %18
  br i1 %19, label %20, label %23

20:                                               ; preds = %13
  %21 = load ptr, ptr %6, align 8, !tbaa !5
  %22 = getelementptr inbounds i8, ptr %21, i32 1
  store ptr %22, ptr %6, align 8, !tbaa !5
  br label %29

23:                                               ; preds = %13
  %24 = load ptr, ptr %6, align 8, !tbaa !5
  %25 = getelementptr inbounds i8, ptr %24, i32 1
  store ptr %25, ptr %6, align 8, !tbaa !5
  %26 = load i8, ptr %24, align 1, !tbaa !9
  %27 = load ptr, ptr %5, align 8, !tbaa !5
  %28 = getelementptr inbounds i8, ptr %27, i32 1
  store ptr %28, ptr %5, align 8, !tbaa !5
  store i8 %26, ptr %27, align 1, !tbaa !9
  br label %29

29:                                               ; preds = %23, %20
  br label %9, !llvm.loop !10

30:                                               ; preds = %9
  %31 = load ptr, ptr %5, align 8, !tbaa !5
  store i8 0, ptr %31, align 1, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  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 @delete_character(ptr nocapture noundef %0, i8 noundef signext %1) local_unnamed_addr #0 {
  %3 = load i8, ptr %0, align 1, !tbaa !5
  %.not11 = icmp eq i8 %3, 0
  br i1 %.not11, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %2, %8
  %4 = phi i8 [ %9, %8 ], [ %3, %2 ]
  %.013 = phi ptr [ %.1, %8 ], [ %0, %2 ]
  %.0812 = phi ptr [ %.19, %8 ], [ %0, %2 ]
  %5 = icmp eq i8 %4, %1
  br i1 %5, label %8, label %6

6:                                                ; preds = %.lr.ph
  %7 = getelementptr inbounds i8, ptr %.0812, i64 1
  store i8 %4, ptr %.0812, align 1, !tbaa !5
  br label %8

8:                                                ; preds = %.lr.ph, %6
  %.19 = phi ptr [ %7, %6 ], [ %.0812, %.lr.ph ]
  %.1 = getelementptr inbounds i8, ptr %.013, i64 1
  %9 = load i8, ptr %.1, 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 = %8, %2
  %.08.lcssa = phi ptr [ %0, %2 ], [ %.19, %8 ]
  store i8 0, ptr %.08.lcssa, align 1, !tbaa !5
  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