[Mesa-dev] tgsi_set_exec_mask?

[Brian Paul]

On 03/20/2016 08:08 PM, Dave Airlie wrote:
> This appears to set some values into some temp register that we never
> read from or look at again,
>
> should it be setting something that ExecMask gets set to at machine run time?
>
> just noticed it while trying to work out the various mask for shader images.

My recollection is that it's supposed to disable execution channels for 
non-existant vertices.  For example, if we only have 3 vertices to 
process, the 4th execution channel should be disabled.

But like you say, it doesn't seem to get used.  I could do a piglit run 
with tgsi_set_exec_mask() nop'd and see what happens...

-Brian