; LLVM IR from AdaptiveCpp/AdaptiveCpp :: src/libkernel/sscp/host/integer.ll_ (acpp_sscp_clz_u16)

; 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 speculatable willreturn memory(none)
declare i32 @llvm.ctlz.i32(i32, i1 immarg) #1

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

; Function Attrs: alwaysinline mustprogress nounwind uwtable
define dso_local zeroext i16 @__acpp_sscp_clz_u16(i16 noundef zeroext %0) #2 {
  %2 = alloca i16, align 2
  %3 = alloca i16, align 2
  %4 = alloca i16, align 2
  store i16 %0, ptr %3, align 2, !tbaa !5
  %5 = load i16, ptr %3, align 2, !tbaa !5
  %6 = zext i16 %5 to i32
  %7 = icmp eq i32 %6, 0
  br i1 %7, label %8, label %9

8:                                                ; preds = %1
  store i16 16, ptr %2, align 2
  br label %15

9:                                                ; preds = %1
  call void @llvm.lifetime.start.p0(i64 2, ptr %4) #3
  store i16 16, ptr %4, align 2, !tbaa !5
  %10 = load i16, ptr %3, align 2, !tbaa !5
  %11 = zext i16 %10 to i32
  %12 = call i32 @llvm.ctlz.i32(i32 %11, i1 true)
  %13 = sub nsw i32 %12, 16
  %14 = trunc i32 %13 to i16
  store i16 %14, ptr %2, align 2
  call void @llvm.lifetime.end.p0(i64 2, ptr %4) #3
  br label %15

15:                                               ; preds = %9, %8
  %16 = load i16, ptr %2, align 2
  ret i16 %16
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
attributes #2 = { alwaysinline 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 }

!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++ TBAA"}


; 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: alwaysinline mustprogress nofree norecurse nosync nounwind willreturn memory(none) uwtable
define dso_local zeroext range(i16 0, 17) i16 @__acpp_sscp_clz_u16(i16 noundef zeroext %0) local_unnamed_addr #0 {
  %2 = tail call range(i16 0, 17) i16 @llvm.ctlz.i16(i16 %0, i1 false)
  ret i16 %2
}

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i16 @llvm.ctlz.i16(i16, i1 immarg) #1

attributes #0 = { alwaysinline mustprogress nofree norecurse nosync nounwind willreturn memory(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" }
attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }

!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)"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass