[Mesa-dev] [PATCH 3/9] nir: Add lowering of POW instructions if the lower flag is set.

[Eric Anholt]

Erik Faye-Lund <kusmabite at gmail.com> writes:

> On Sun, Feb 1, 2015 at 10:17 PM, Eric Anholt <eric at anholt.net> wrote:
>> This could be done in a separate pass like we do in GLSL IR, but it seems
>> to me like having the definitions of the transformations in the two
>> directions next to each other makes a lot of sense.
>> ---
>>  src/glsl/nir/nir_opt_algebraic.py | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
>> index 2414f71..41bfe04 100644
>> --- a/src/glsl/nir/nir_opt_algebraic.py
>> +++ b/src/glsl/nir/nir_opt_algebraic.py
>> @@ -107,6 +107,7 @@ optimizations = [
>>     (('fexp',  ('flog',  a)), a), # e^ln(a)  = a
>>     (('flog2', ('fexp2', a)), a), # lg2(2^a) = a
>>     (('flog',  ('fexp',  a)), a), # ln(e^a)  = a
>> +   (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # 2^(lg2(a)*b) = a^b
>
> Maybe update the comment to be "# a^b = 2^(lg2(a)*b)" instead? That
> way you're consistent with the other rewrite-rules that seems to list
> the source expression first and the replacement second...

Done.
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