[Mesa-dev] [PATCH 4/6] glsl: mark xfb inputs as always_active_io

[Timothy Arceri]

On 10/10/17 09:31, Eric Anholt wrote:
> Timothy Arceri <tarceri at itsqueeze.com> writes:
> 
>> We won't split varyings marked as always active because there
>> is no point in doing so. This means we need to mark both
>> sides of the interface as always active otherwise we will have
>> a mismatch and start removing things we shouldn't.
> 
> Is this just needed because the next patch only updates a single bit in
> the read/write arrays for multi-channel variables?  Or is there
> something else?

We want to keep both sides the same. We don't want to have:

vec4 on one side and float * 4 on the other. We might be able to handle 
it but just for the simple readability of NIR dumps I don't think we 
should do it. Thoughts?

> 
> If there's nothing else, then updating the NIR pass for tracking all of
> the channels seems pretty doable and would have fewer magic requirements
> between stages.
>