SVE support in Xcode-beta?

I'm trying to understand if the Xcode beta includes support for SVE which then in theory might also mean Apple Silicon could have support for it since again in theory it's post armv8.2-a hardware. Obviously SVE is an optional feature, but as a software dev it'd be good to know one way or another. Certainly NEON will be around.

From what I've seen

neither
#ifdef _ARMFEATURESVE
nor
#include <arm
sve.h>
exist.

yet:
clang happily accepts -march=armv8-a+sve

As it's more than reasonable that other defines or includes that are specific to the Apple ecosystem would be what to use thought I'd ask.

Thanks!