Well, RAW image formats vary per camera, so it probably won't "support" any particular format out of the box since that is not really the responsibility of the language.
But given a known format I'm pretty sure you can convert any RAW image format into something Halide understands without loss (at the moment most RAW image data uses at most 14 bits IIRC, so a 16 bit RGB array should be enough), after which you can implement, say, debayering algorithms yourself.
In fact, that's the first example you see in the first publication (see top left) about Halide:
But given a known format I'm pretty sure you can convert any RAW image format into something Halide understands without loss (at the moment most RAW image data uses at most 14 bits IIRC, so a 16 bit RGB array should be enough), after which you can implement, say, debayering algorithms yourself.
In fact, that's the first example you see in the first publication (see top left) about Halide:
http://people.csail.mit.edu/jrk/halide12/