@uniforms dependent on @index values fail

[leios]

I may have missed something important, but this code is currently failing on the CPU

using KernelAbstractions

@kernel function f_test_kernel!(input)
    tid = @index(Global, Linear)
    @uniform a = tid

end

function f_test!(input; numcores = 4, numthreads = 256)

    if isa(input, Array)
        kernel! = f_test_kernel!(CPU(), numcores)
    else
        kernel! = f_test_kernel!(CUDADevice(), numthreads)
    end

    kernel!(input, ndrange=size(input))
end

f_test!(zeros(10))

With tid not defined:

julia> wait(f_test!(zeros(10)))
ERROR: TaskFailedException
Stacktrace:
 [1] wait
   @ ./task.jl:322 [inlined]
 [2] wait
   @ ~/projects/KernelAbstractions.jl/src/cpu.jl:65 [inlined]
 [3] wait (repeats 2 times)
   @ ~/projects/KernelAbstractions.jl/src/cpu.jl:29 [inlined]
 [4] top-level scope
   @ REPL[3]:1
 [5] top-level scope
   @ ~/.julia/packages/CUDA/YpW0k/src/initialization.jl:52

    nested task error: UndefVarError: tid not defined
    Stacktrace:
     [1] cpu_f_test_kernel!(::KernelAbstractions.CompilerMetadata{KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.DynamicCheck, CartesianIndex{1}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, KernelAbstractions.NDIteration.NDRange{1, KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.StaticSize{(4,)}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, Nothing}}, ::Vector{Float64})
       @ ./none:0 [inlined]
     [2] overdub
       @ ./none:0 [inlined]
     [3] __thread_run(tid::Int64, len::Int64, rem::Int64, obj::KernelAbstractions.Kernel{CPU, KernelAbstractions.NDIteration.StaticSize{(4,)}, KernelAbstractions.NDIteration.DynamicSize, typeof(cpu_f_test_kernel!)}, ndrange::Tuple{Int64}, iterspace::KernelAbstractions.NDIteration.NDRange{1, KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.StaticSize{(4,)}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, Nothing}, args::Tuple{Vector{Float64}}, dynamic::KernelAbstractions.NDIteration.DynamicCheck)
       @ KernelAbstractions ~/projects/KernelAbstractions.jl/src/cpu.jl:157
     [4] __run(obj::KernelAbstractions.Kernel{CPU, KernelAbstractions.NDIteration.StaticSize{(4,)}, KernelAbstractions.NDIteration.DynamicSize, typeof(cpu_f_test_kernel!)}, ndrange::Tuple{Int64}, iterspace::KernelAbstractions.NDIteration.NDRange{1, KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.StaticSize{(4,)}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, Nothing}, args::Tuple{Vector{Float64}}, dynamic::KernelAbstractions.NDIteration.DynamicCheck)
       @ KernelAbstractions ~/projects/KernelAbstractions.jl/src/cpu.jl:130
     [5] (::KernelAbstractions.var"#33#34"{Nothing, Nothing, typeof(KernelAbstractions.__run), Tuple{KernelAbstractions.Kernel{CPU, KernelAbstractions.NDIteration.StaticSize{(4,)}, KernelAbstractions.NDIteration.DynamicSize, typeof(cpu_f_test_kernel!)}, Tuple{Int64}, KernelAbstractions.NDIteration.NDRange{1, KernelAbstractions.NDIteration.DynamicSize, KernelAbstractions.NDIteration.StaticSize{(4,)}, CartesianIndices{1, Tuple{Base.OneTo{Int64}}}, Nothing}, Tuple{Vector{Float64}}, KernelAbstractions.NDIteration.DynamicCheck}})()
       @ KernelAbstractions ~/projects/KernelAbstractions.jl/src/cpu.jl:22

In my case, I wanted to use @uniform elem = input[tid] as a separate element variable, which I expect to be a fairly common use-case

[albertomercurio]

I have the same issue.

[vchuravy]

Very belatedly, but @index is a non-uniform statement (with maybe @index(Group)) being an exception. So yeah this is expected to not work.