[Piglit] [PATCH] cl: Add tests for mad mix

[Matt Arsenault]

> On Oct 5, 2017, at 12:33, Jan Vesely <jan.vesely at rutgers.edu> wrote:
> 
> 
> ah, that makes more sense. Do you mind if I add it to the commit
> message? (I'll also fix the formatting nits) with that
> 
> Reviewed-by: Jan Vesely <jan.vesely at rutgers.edu>
> 
> out of curiosity what's the use of having these in piglit? supposedly
> the instruction selection and encoding part is tested in llvm lit. Is
> this testing whether the instruction works correctly? shouldn't the hw
> design team have tests for that?
> 
> Jan

We can test an encoding in the lit tests, but we can’t actually check that it works. I don’t really trust the encoding tests until there’s something executing it. A lot of times in the past we’ve gotten the encodings wrong and the instruction doesn’t work, or the manual has had an off by one error in some of the encodings.

-Matt