simdloop.jl
# This file is a part of Julia. License is MIT: https://julialang.org/license
function simd_loop_example_from_manual(x, y, z)
s = zero(eltype(z))
n = min(length(x),length(y),length(z))
@simd for i in 1:n
@inbounds begin
z[i] = x[i]-y[i]
s += z[i]*z[i]
end
end
s
end
function simd_loop_axpy!(a, X, Y)
@simd ivdep for i in eachindex(X)
@inbounds Y[i] += a*X[i]
end
return Y
end
function simd_loop_with_multiple_reductions(x, y, z)
# Use non-zero initial value to make sure reduction values include it.
(s,t) = (one(eltype(x)),one(eltype(y)))
@simd for i in 1:length(z)
@inbounds begin
s += x[i]
t += 2*y[i]
s += z[i] # Two reductions go into s
end
end
(s,t)
end
for T in [Int32,Int64,Float32,Float64]
# Try various lengths to make sure "remainder loop" works
for n in [0,1,2,3,4,255,256,257]
local n, a, b, c, s, t
# Dataset chosen so that results will be exact with only 24 bits of mantissa
a = convert(Array{T},[2*j+1 for j in 1:n])
b = convert(Array{T},[3*j+2 for j in 1:n])
c = convert(Array{T},[5*j+3 for j in 1:n])
s = simd_loop_example_from_manual(a,b,c)
@test a==[2*j+1 for j in 1:n]
@test b==[3*j+2 for j in 1:n]
@test c==[-j-1 for j in 1:n]
@test s==sum(c.*c)
(s,t) = simd_loop_with_multiple_reductions(a,b,c)
@test s==sum(a)+sum(c)+1
@test t==2*sum(b)+1
X = ones(T, n)
Y = zeros(T, n)
simd_loop_axpy!(T(2), X, Y)
@test all(y->y==T(2), Y)
end
end
# Test that scope rules match regular for
let j=4, k=4
# Use existing local variable.
@simd for j=1:0 end
for k=1:0 end
@test j==k
@simd for j=1:3 end
for k=1:3 end
@test j==k
# Use global variable
global simd_glob = 4
global glob = 4
@simd for simd_glob=1:0 end
for glob=1:0 end
@test simd_glob==glob
@simd for simd_glob=1:3 end
for glob=1:3 end
@test simd_glob==glob
# Index that is local to loop
@simd for simd_loop_local=1:0 end
simd_loop_local_present = true
try
simd_loop_local += 1
catch
simd_loop_local_present = false
end
@test !simd_loop_local_present
end
import Base.SimdLoop.SimdError
# Test that @simd rejects inner loop body with invalid control flow statements
# issue #8613
@test_throws SimdError("break is not allowed inside a @simd loop body") @macroexpand begin
@simd for x = 1:10
x == 1 && break
end
end
@test_throws SimdError("continue is not allowed inside a @simd loop body") @macroexpand begin
@simd for x = 1:10
x < 5 && continue
end
end
@test_throws SimdError("@goto is not allowed inside a @simd loop body") @macroexpand begin
@simd for x = 1:10
x == 1 || @goto exit_loop
end
@label exit_loop
end
# @simd with cartesian iteration
function simd_cartesian_range!(indices, crng)
@simd for I in crng
push!(indices, I)
end
indices
end
crng = CartesianIndices(map(Base.Slice, (2:4, 0:1, 1:1, 3:5)))
indices = simd_cartesian_range!(Vector{eltype(crng)}(), crng)
@test indices == vec(collect(crng))
crng = CartesianIndices(map(Base.Slice, (-1:1, 1:3)))
indices = simd_cartesian_range!(Vector{eltype(crng)}(), crng)
@test indices == vec(collect(crng))
crng = CartesianIndices(map(Base.Slice, (-1:-1, 1:3)))
indices = simd_cartesian_range!(Vector{eltype(crng)}(), crng)
@test indices == vec(collect(crng))
crng = CartesianIndices(map(Base.Slice, (2:4,)))
indices = simd_cartesian_range!(Vector{eltype(crng)}(), crng)
@test indices == collect(crng)
crng = CartesianIndices(())
indices = simd_cartesian_range!(Vector{eltype(crng)}(), crng)
@test indices == vec(collect(crng))
# @simd with array as "range"
# issue #13869
function simd_sum_over_array(a)
s = zero(eltype(a))
@inbounds @simd for x in a
s += x
end
s
end
@test 2001000 == simd_sum_over_array(Vector(1:2000))
@test 2001000 == simd_sum_over_array(Float32[i+j*500 for i=1:500, j=0:3])
#Opt out of simd
struct iter31113{T}
parent::T
end
Base.iterate(it::iter31113, args...) = iterate(it.parent, args...)
Base.eltype(it::iter31113) = eltype(it.parent)
Base.SimdLoop.simd_index(v::iter31113, j, i) = j
Base.SimdLoop.simd_inner_length(v::iter31113, j) = 1
Base.SimdLoop.simd_outer_range(v::iter31113) = v
@test 2001000 == simd_sum_over_array(iter31113(Vector(1:2000)))