circshift code generation fails

I'm trying to go through the code generation process to make an FDM model as quick as possible for use in another program. To find boundaries and assign boundary conditions, I need to shift a 3D mask in all 3 dimensions. Originally, to do this I used imtranslate. However, code generation is not supported for 3D calls of imtranslate. I switched to circshift, which effectively does the same thing. However, when I run through the code generation process, I get a "Function call failed" error every time I call circshift. MATLAB says it supports circshift for code generation, so I'm clearly missing something.

Since the size of my 3D mask varies, I left all the dimensions unbounded. Could this be the source of the problem? Are there any other methods for simply shifting an array over by one in a dimension that is compatible with code generation?