[Mesa-dev] [PATCH 8/8] i965/vec4: Do copy before constant propagation after opt_vector_float().

[Ian Romanick]

On 12/23/2014 08:26 AM, Matt Turner wrote:
> On 12/22/14, Ian Romanick <idr at freedesktop.org> wrote:
>> On 12/21/2014 03:24 PM, Matt Turner wrote:
>>> total instructions in shared programs: 5877012 -> 5876617 (-0.01%)
>>> instructions in affected programs:     33140 -> 32745 (-1.19%)
>>>
>>> From before the commit that allows VF constant propagation (which hurt
>>> some programs) to here, the results are:
>>>
>>> total instructions in shared programs: 5877951 -> 5876617 (-0.02%)
>>> instructions in affected programs:     123444 -> 122110 (-1.08%)
>>>
>>> with no programs hurt.
>>> ---
>>>  src/mesa/drivers/dri/i965/brw_vec4.cpp | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp
>>> b/src/mesa/drivers/dri/i965/brw_vec4.cpp
>>> index d36a735..c9ba338 100644
>>> --- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
>>> +++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
>>> @@ -1800,6 +1800,7 @@ vec4_visitor::run()
>>>
>>>     if (opt_vector_float()) {
>>>        opt_cse();
>>> +      opt_copy_propagation(false);
>>
>> The commit messages suggest the above line should go before the
>> opt_cse() call.
> 
> Right, saying "after opt_cse()" seems too general though. How about:
> 
>> i965/vec4: Do separate copy followed by constant propagation after opt_vector_float().

That works for me.

>>>        opt_copy_propagation();
>>
>> Seeing these two lines together makes the default parameter to
>> opt_copy_propagation feel a little icky... but I guess the
>> OPT(opt_copy_propagation()) in vec4_visitor::run won't really work
>> otherwise.
>>
>> Maybe pass an explicit true here anyway?
> 
> The OPT macro is actually variadic and passes extra arguments to the
> optimization pass, but I think I like the default argument there, and
> explicitly passing true/false in the opt_vector_float() block to show
> explicitly what's going on.

With the changes you've proposed here and in patch 2, the series is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>