[Mesa-dev] [PATCH 0/4] i965: skip control-flow aware liveness analysis if we only have 1 block

[Jordan Justen]

On 2015-10-13 22:49:08, Iago Toral wrote:
> On Tue, 2015-10-13 at 09:44 -0700, Jordan Justen wrote:
> > On 2015-10-13 05:17:37, Francisco Jerez wrote:
> > > Iago Toral Quiroga <itoral at igalia.com> writes:
> > > 
> > > > This fixes the following test:
> > > >
> > > > [require]
> > > > GL >= 3.3
> > > > GLSL >= 3.30
> > > > GL_ARB_shader_storage_buffer_object
> > > >
> > > > [fragment shader]
> > > > #version 330
> > > > #extension GL_ARB_shader_storage_buffer_object: require
> > > >
> > > > buffer SSBO {
> > > >     mat4 sm4;
> > > > };
> > > >
> > > >
> > > > mat4 um4;
> > > >
> > > > void main() {
> > > >     sm4 *= um4;
> > > 
> > > This is using the value of "um4", which is never assigned, so liveness
> > > analysis will correctly extend its live interval up to the start of the
> > > block.
> > 
> > This test was derived by simplifying a CTS test case.
> > 
> > Anyway, I'm not sure what happened on the way to the commit message,
> > but um4 should be a uniform.
> > 
> > http://sprunge.us/cEUe
> 
> Oh yes, that was me playing around with the example. The patches also
> fix the uniform version. Jordan, can you verify if this fixes the CTS
> test case?

Unfortunately, no. The CTS case has some control flow. I had removed
it to minimize the test case.

Here is a small shader_test that has control flow and still fails to
compile with your patches:

http://sprunge.us/LIjA

> In any case, since Curro is working on a more general fix for this
> stuff, I guess you'd rather wait for his patches...

It depends how long we'd have to wait. :) Anyway, since we don't have
a short-term fix anyhow, let's wait to see what curro has to say.

-Jordan