ReadVertex took the GE's viewport arithmetic one coordinate at a time,
with a reciprocal of w for each, and stored the position, the UVs and
the whole vertex in pieces that were then reloaded with wider loads,
each a store forwarding stall. x, y and z now go through one GERecip and
the four-lane multiply and add (the scalar path stays for non-finite
input and zero or denormal w), the position is loaded as a vector, and
the vertex is written straight into its destination.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
