[Mesa-dev] [PATCH 2/5] nir: Recognize sum of open-coded pow()s.

[Matt Turner]

On Mon, Feb 8, 2016 at 12:01 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> On Thu, Feb 4, 2016 at 5:47 PM, Matt Turner <mattst88 at gmail.com> wrote:
>>
>> Prevents regressions in the next commit.
>> ---
>>  src/compiler/nir/nir_opt_algebraic.py | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/src/compiler/nir/nir_opt_algebraic.py
>> b/src/compiler/nir/nir_opt_algebraic.py
>> index 60df69f..0a248a2 100644
>> --- a/src/compiler/nir/nir_opt_algebraic.py
>> +++ b/src/compiler/nir/nir_opt_algebraic.py
>> @@ -167,6 +167,7 @@ optimizations = [
>>     (('flog2', ('fexp2', a)), a), # lg2(2^a) = a
>>     (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)),
>> 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
>>     (('fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b),
>> '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
>> +   (('fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c),
>> d))), ('fadd', ('fpow', a, b), ('fpow', c, d))),
>
>
> I think you mean ('fmul', ('fpow', a, b), ('fpow', c, d)).  You can't pull
> an add out of an exp and get another add.

Whoops. Yes, thank you!