; LLVM IR from m-boutaleb/LZS :: src (buffer_service)

; 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"

@buffer_size = external hidden global i16, align 2
@buffer = external hidden global i8, align 1

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

; Function Attrs: nounwind uwtable
define dso_local zeroext i8 @read_1bit() #1 {
  %1 = alloca i8, align 1
  %2 = load i16, ptr @buffer_size, align 2, !tbaa !5
  %3 = zext i16 %2 to i32
  %4 = icmp eq i32 %3, 0
  br i1 %4, label %5, label %6

5:                                                ; preds = %0
  call void @read_buffer()
  store i16 8, ptr @buffer_size, align 2, !tbaa !5
  br label %6

6:                                                ; preds = %5, %0
  call void @llvm.lifetime.start.p0(i64 1, ptr %1) #2
  %7 = load i8, ptr @buffer, align 1, !tbaa !9
  %8 = zext i8 %7 to i32
  %9 = ashr i32 %8, 7
  %10 = trunc i32 %9 to i8
  store i8 %10, ptr %1, align 1, !tbaa !9
  %11 = load i8, ptr @buffer, align 1, !tbaa !9
  %12 = zext i8 %11 to i32
  %13 = shl i32 %12, 1
  %14 = trunc i32 %13 to i8
  store i8 %14, ptr @buffer, align 1, !tbaa !9
  %15 = load i16, ptr @buffer_size, align 2, !tbaa !5
  %16 = add i16 %15, -1
  store i16 %16, ptr @buffer_size, align 2, !tbaa !5
  %17 = load i8, ptr %1, align 1, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 1, ptr %1) #2
  ret i8 %17
}

; 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
declare hidden void @read_buffer() #1

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 = !{!"short", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!7, !7, i64 0}


; 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"

@buffer_size = external hidden local_unnamed_addr global i16, align 2
@buffer = external hidden local_unnamed_addr global i8, align 1

; Function Attrs: nounwind uwtable
define dso_local zeroext range(i8 0, 2) i8 @read_1bit() local_unnamed_addr #0 {
  %1 = load i16, ptr @buffer_size, align 2, !tbaa !5
  %2 = icmp eq i16 %1, 0
  br i1 %2, label %3, label %4

3:                                                ; preds = %0
  tail call void @read_buffer()
  br label %4

4:                                                ; preds = %3, %0
  %5 = phi i16 [ 8, %3 ], [ %1, %0 ]
  %6 = load i8, ptr @buffer, align 1, !tbaa !9
  %7 = lshr i8 %6, 7
  %8 = shl i8 %6, 1
  store i8 %8, ptr @buffer, align 1, !tbaa !9
  %9 = add i16 %5, -1
  store i16 %9, ptr @buffer_size, align 2, !tbaa !5
  ret i8 %7
}

; Function Attrs: nounwind uwtable
declare hidden void @read_buffer() local_unnamed_addr #0

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" }

!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 = !{!"short", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!7, !7, i64 0}


; Effective O3 passes: DSEPass,EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,SROAPass,TailCallElimPass