[Mesa-dev] [PATCH 00/10] i965: Silly vec4 un/packing optimizations

[Matt Turner]

When I implemented these built-ins couple of years ago, I thought there
must be a neat way to optimize them. I tried a couple of things with the
different vector immediates i965 provides, but the V/UV types are too
small to represent the appropriate shift values, and shift instructions
can't shift by a floating-point source (if using the vector float imm).

Curro pointed out that I could actually load the integer shift values
with VF immediate just by doing a type converting move. How simple.

So anyway, these optimizations are of pretty negligible value, except
for maybe demonstrating that VF works. I've had them sitting on a branch
for months, so time for them to live somewhere else. At least we can
disassemble VF immediates now.

I hope to have some more uses of VF immediates soon too.