; 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"

; Function Attrs: nounwind uwtable
define dso_local zeroext i16 @read_offset(i16 noundef zeroext %0) #0 {
  %2 = alloca i16, align 2
  %3 = alloca i16, align 2
  %4 = alloca i32, align 4
  store i16 %0, ptr %2, align 2, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 2, ptr %3) #2
  store i16 0, ptr %3, align 2, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 1, ptr %4, align 4, !tbaa !9
  br label %5

5:                                                ; preds = %22, %1
  %6 = load i32, ptr %4, align 4, !tbaa !9
  %7 = load i16, ptr %2, align 2, !tbaa !5
  %8 = zext i16 %7 to i32
  %9 = icmp ne i32 %8, 0
  %10 = zext i1 %9 to i64
  %11 = select i1 %9, i32 12, i32 8
  %12 = icmp slt i32 %6, %11
  br i1 %12, label %14, label %13

13:                                               ; preds = %5
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %25

14:                                               ; preds = %5
  %15 = load i16, ptr %3, align 2, !tbaa !5
  %16 = zext i16 %15 to i32
  %17 = shl i32 %16, 1
  %18 = call zeroext i8 @read_1bit()
  %19 = zext i8 %18 to i32
  %20 = or i32 %17, %19
  %21 = trunc i32 %20 to i16
  store i16 %21, ptr %3, align 2, !tbaa !5
  br label %22

22:                                               ; preds = %14
  %23 = load i32, ptr %4, align 4, !tbaa !9
  %24 = add nsw i32 %23, 1
  store i32 %24, ptr %4, align 4, !tbaa !9
  br label %5, !llvm.loop !11

25:                                               ; preds = %13
  %26 = load i16, ptr %3, align 2, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 2, ptr %3) #2
  ret i16 %26
}

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

; Function Attrs: nounwind uwtable
declare dso_local zeroext i8 @read_1bit() #0

; 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 = !{!"short", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"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: nounwind uwtable
define dso_local zeroext i16 @read_offset(i16 noundef zeroext %0) local_unnamed_addr #0 {
  %.not = icmp eq i16 %0, 0
  %2 = select i1 %.not, i32 8, i32 12
  br label %4

3:                                                ; preds = %4
  ret i16 %8

4:                                                ; preds = %1, %4
  %.07 = phi i32 [ 1, %1 ], [ %9, %4 ]
  %.056 = phi i16 [ 0, %1 ], [ %8, %4 ]
  %5 = shl i16 %.056, 1
  %6 = tail call zeroext i8 @read_1bit()
  %7 = zext i8 %6 to i16
  %8 = or i16 %5, %7
  %9 = add nuw nsw i32 %.07, 1
  %exitcond.not = icmp eq i32 %9, %2
  br i1 %exitcond.not, label %3, label %4, !llvm.loop !5
}

; Function Attrs: nounwind uwtable
declare dso_local zeroext i8 @read_1bit() 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 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


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