[PATCH][AArch64] Add support for vget/vset_lane_f16 ACLE functions

[Tim Northover]

Hi Chad,

> I'm checking the target triple to allow for half-float arguments/return
> types in Sema.  However, I'm currently looking into defining the AArch64
> PCS as an alternative solution.  I was hoping we could get these patches
> into the 3.4 release, so I'm sending patches with the less invasive change
> for now.

I don't think this is the right solution. ACLE itself says that __fp16
(and by extension float16_t) should *not* be permitted as an argument
or return type (section 4.1.2). That should make this patch rather
easier, actually.

Cheers.

Tim.