Merge pull request #20817 from Sacha0/tuplebc

fast broadcast over combinations of tuples and scalars

Author: pabloferz

base/broadcast.jl

@@ -297,11 +297,6 @@ _broadcast_eltype(f, A, Bs...) = Base._return_type(f, eltypestuple(A, Bs...))
     end
     return broadcast_t(f, Any, shape, iter, A, Bs...)
 end
-function broadcast_c(f, ::Type{Tuple}, As...)
-    shape = broadcast_indices(As...)
-    n = length(shape[1])
-    return ntuple(k->f((_broadcast_getindex(A, k) for A in As)...), n)
-end
 @inline function broadcast_c(f, ::Type{Nullable}, a...)
     nonnull = all(hasvalue, a)
     S = _broadcast_eltype(f, a...)
@@ -316,6 +311,20 @@ end
     end
 end
 @inline broadcast_c(f, ::Type{Any}, a...) = f(a...)
+broadcast_c(f, ::Type{Tuple}, As...) =
+    ntuple(k -> f(_tuplebroadcast_getargs(As, k)...), _tuplebroadcast_reslength(As))
+broadcast_c{T}(f, ::Type{Tuple}, ::Type{T}, As...) =
+    ntuple(k -> f(T, _tuplebroadcast_getargs(As, k)...), _tuplebroadcast_reslength(As))
+@inline _tuplebroadcast_getargs(::Tuple{}, k) = ()
+@inline _tuplebroadcast_getargs(As, k) =
+    (_broadcast_getindex(first(As), k), _tuplebroadcast_getargs(tail(As), k)...)
+@noinline _tuplebroadcast_reslength(As) =
+    _tuplebroadcast_maxlength(_tuplebroadcast_length(first(As)), tail(As))
+@inline _tuplebroadcast_maxlength(l, As) =
+    _tuplebroadcast_maxlength(max(l, _tuplebroadcast_length(first(As))), tail(As))
+@inline _tuplebroadcast_maxlength(l, ::Tuple{}) = l
+@inline _tuplebroadcast_length(t::Tuple) = length(t)
+@inline _tuplebroadcast_length(s) = 1
 
 """
     broadcast(f, As...)