fixup N support

Author: vchuravy

src/KernelAbstractions.jl

@@ -82,6 +82,8 @@ macro kernel(ex...)
             elseif ex[i] isa Expr && ex[i].head == :(=) &&
                     ex[i].args[1] == :inbounds && ex[i].args[2] isa Bool
                 force_inbounds = ex[i].args[2]
+            elseif ex[i] isa Int
+                N = StaticSize(ex[i])
             else
                 error(
                     "Configuration should be of form:\n" *
@@ -659,7 +661,10 @@ Partition a kernel for the given ndrange and workgroupsize.
     end
 
     if static_ndims <: StaticSize
-        @assert get(static_ndims) == length(ndrange)
+        N = only(get(static_ndims))
+        if N !== length(ndrange)
+            error("Mismatch between static kernel dimension (N=$N) and ndrange=$ndrange")
+        end
     end
 
     # TODO: Add static_ndims

test/runtests.jl

@@ -21,6 +21,17 @@ kern_static(CPU(static = true), (1,))(A, ndrange = length(A))
 end
 @test_throws ErrorException("This kernel is unavailable for backend CPU") my_no_cpu_kernel(CPU())
 
+@kernel 1 function OneD()
+end
+
+@kernel 2 function TwoD()
+end
+
+@test OneD(CPU())(ndrange=1024) === nothing
+@test_throws ErrorException("Mismatch between static kernel dimension (N=1) and ndrange=(1024, 1)") OneD(CPU())(ndrange=(1024, 1))
+@test_throws ErrorException("Mismatch between static kernel dimension (N=2) and ndrange=(1024, 1)") TwoD(CPU())(ndrange=1024)
+@test TwoD(CPU())(ndrange=(1024,1)) === nothing
+
 # testing multiple configurations at the same time
 @kernel cpu = false inbounds = false function my_no_cpu_kernel2(a)
 end