UndefVarError when variable is defined

[efaulhaber]

using KernelAbstractions

@kernel function mykernel(y)
    z = length(y)

    for i in 1:z
        @synchronize
    end
end

x = zeros(3)
backend = get_backend(x)

mykernel(backend)(x; ndrange=length(x))

KernelAbstractions.synchronize(backend)

This MWE yields:

ERROR: UndefVarError: `z` not defined in `Main`
Suggestion: check for spelling errors or missing imports.
Stacktrace:
 [1] cpu_mykernel
   @ ~/.julia/packages/KernelAbstractions/lGrz7/src/macros.jl:307 [inlined]
 [2] cpu_mykernel(__ctx__::KernelAbstractions.CompilerMetadata{…}, x::Vector{…})
   @ Main ./none:0
 [3] __thread_run(tid::Int64, len::Int64, rem::Int64, obj::KernelAbstractions.Kernel{…}, ndrange::Tuple{…}, iterspace::KernelAbstractions.NDIteration.NDRange{…}, args::Tuple{…}, dynamic::KernelAbstractions.NDIteration.NoDynamicCheck)
   @ KernelAbstractions ~/.julia/packages/KernelAbstractions/lGrz7/src/cpu.jl:145
 [4] __run(obj::KernelAbstractions.Kernel{…}, ndrange::Tuple{…}, iterspace::KernelAbstractions.NDIteration.NDRange{…}, args::Tuple{…}, dynamic::KernelAbstractions.NDIteration.NoDynamicCheck, static_threads::Bool)
   @ KernelAbstractions ~/.julia/packages/KernelAbstractions/lGrz7/src/cpu.jl:112
 [5] (::KernelAbstractions.Kernel{…})(args::Vector{…}; ndrange::Int64, workgroupsize::Nothing)
   @ KernelAbstractions ~/.julia/packages/KernelAbstractions/lGrz7/src/cpu.jl:46
 [6] top-level scope
   @ Untitled-2:14
Some type information was truncated. Use `show(err)` to see complete types.

[efaulhaber]

Update: It seems to work on the GPU, but I would love to run it on the CPU for debugging because I'm getting illegal memory access on the GPU with my larger kernel.

[yolhan83]

Are you on main ? otherwise use @uniform,

@kernel function mykernel(y)
    @uniform z = length(y)

    for i in 1:z
        @synchronize
    end
end

edit : it does not work, synchronize in loops doesn't work on the old CPU backend.

use add KernelAbstraction#main and your code it works thanks to the Pocl backend. So its fixed on main.