1. Does simd work for Integer types?
code_llvm shows vector.body section for Int16,Int32,Float32,Float64 but not
for Int64. (on my Windows 64 machine, Julia v0.4.1)
Speedup is seen for Float32 and to lesser extent Float64, as expected.
Integers show no speed up. Is this because simd is applied implicitly?
Why is Int64 apparently not using simd?
buf = IOBuffer()
n = 10000
reps = 1000
for T in (Int16,Int32,Int64,Float32,Float64)
code_llvm(buf, innersimd, Tuple{Vector{T},Vector{T}})
println(T, " ", contains(takebuf_string(buf), "vector.body"))
timeit(T, n, reps)
end
Int16 true
GFlop Int16 = 14.329049425190183
GFlop Int16 (SIMD) = 14.64120268695352
Int32 true
GFlop Int32 = 4.339303129613899
GFlop Int32 (SIMD) = 4.436321047681579
Int64 false
GFlop Int64 = 2.1942537759816103
GFlop Int64 (SIMD) = 2.195101499298226
Float32 true
GFlop Float32 = 2.1954870446504984
GFlop Float32 (SIMD) = 7.82465266366826
Float64 true
GFlop Float64 = 2.171535919755667
GFlop Float64 (SIMD) = 4.0068798126383
2. Can simd be applied to unrolled statements? Perhaps using some form of
meta expression?
begin
Expr(:meta, :simd)
s = 0
s += x[1]*y[1]
s += x[2]*y[2]
s += x[3]*y[3]
s += x[4]*y[4]
s += x[5]*y[5]
s += x[6]*y[6]
s += x[7]*y[7]
s += x[8]*y[8]
end
