Revert "Revert "Generalize broadcast!(f, ::BitVector) optimization …

…to `BitArray`." (JuliaLang#52775)"

This reverts commit 11bb62b.

base/broadcast.jl

@@ -974,53 +974,42 @@ preprocess(dest, x) = extrude(broadcast_unalias(dest, x))
  return dest
 end
 
-# Performance optimization: for BitVector outputs, we cache the result
-# in a 64-bit register before writing into memory (to bypass LSQ)
-@inline function copyto!(dest::BitVector, bc::Broadcasted{Nothing})
- axes(dest) == axes(bc) || throwdm(axes(dest), axes(bc))
- ischunkedbroadcast(dest, bc) && return chunkedcopyto!(dest, bc)
- destc = dest.chunks
- bcp = preprocess(dest, bc)
- length(bcp) <= 0 && return dest
- len = Base.num_bit_chunks(Int(length(bcp)))
- @inbounds for i = 0:(len - 2)
- z = UInt64(0)
- for j = 0:63
- z |= UInt64(bcp[i*64 + j + 1]::Bool) << (j & 63)
- end
- destc[i + 1] = z
- end
- @inbounds let i = len - 1
- z = UInt64(0)
- for j = 0:((length(bcp) - 1) & 63)
- z |= UInt64(bcp[i*64 + j + 1]::Bool) << (j & 63)
- end
- destc[i + 1] = z
- end
- return dest
-end
-
 # Performance optimization: for BitArray outputs, we cache the result
-# in a "small" Vector{Bool}, and then copy in chunks into the output
+# in a 64-bit register before writing into memory (to bypass LSQ)
 @inline function copyto!(dest::BitArray, bc::Broadcasted{Nothing})
  axes(dest) == axes(bc) || throwdm(axes(dest), axes(bc))
  ischunkedbroadcast(dest, bc) && return chunkedcopyto!(dest, bc)
- length(dest) < 256 && return invoke(copyto!, Tuple{AbstractArray, Broadcasted{Nothing}}, dest, bc)
- tmp = Vector{Bool}(undef, bitcache_size)
- destc = dest.chunks
- cind = 1
+ ndims(dest) == 0 && (dest[] = bc[]; return dest)
  bc′ = preprocess(dest, bc)
- @inbounds for P in Iterators.partition(eachindex(bc′), bitcache_size)
- ind = 1
- @simd for I in P
- tmp[ind] = bc′[I]
- ind += 1
+ ax = axes(bc′)
+ ax1, out = ax[1], CartesianIndices(tail(ax))
+ destc, indc = dest.chunks, 0
+ bitst, remain = 0, UInt64(0)
+ for I in out
+ i = first(ax1) - 1
+ if ndims(bc) == 1 || bitst >= 64 - length(ax1)
+ if ndims(bc) > 1 && bitst != 0
+ @inbounds @simd for j = bitst:63
+ remain |= UInt64(convert(Bool, bc′[i+=1, I])) << (j & 63)
+ end
+ @inbounds destc[indc+=1] = remain
+ bitst, remain = 0, UInt64(0)
+ end
+ while i <= last(ax1) - 64
+ z = UInt64(0)
+ @inbounds @simd for j = 0:63
+ z |= UInt64(convert(Bool, bc′[i+=1, I])) << (j & 63)
+ end
+ @inbounds destc[indc+=1] = z
+ end
  end
- @simd for i in ind:bitcache_size
- tmp[i] = false
+ @inbounds @simd for j = i+1:last(ax1)
+ remain |= UInt64(convert(Bool, bc′[j, I])) << (bitst & 63)
+ bitst += 1
  end
- dumpbitcache(destc, cind, tmp)
- cind += bitcache_chunks
+ end
+ @inbounds if bitst != 0
+ destc[indc+=1] = remain
  end
  return dest
 end

test/broadcast.jl

@@ -592,6 +592,16 @@ end
  end
 end
 
+@testset "convert behavior of logical broadcast" begin
+ a = mod.(1:4, 2)
+ @test !isa(a, BitArray)
+ for T in (Array{Bool}, BitArray)
+ la = T(a)
+ la .= mod.(0:3, 2)
+ @test la == [false; true; false; true]
+ end
+end
+
 # Test that broadcast treats type arguments as scalars, i.e. containertype yields Any,
 # even for subtypes of abstract array. (https://github.com/JuliaStats/DataArrays.jl/issues/229)
 @testset "treat type arguments as scalars, DataArrays issue 229" begin