[Mesa-dev] [PATCH] nir: Add a couple of iand/ior optimizations

[Timothy Arceri]

On 24/07/18 00:10, Jason Ekstrand wrote:
> On Mon, Jul 23, 2018 at 1:08 AM Timothy Arceri <tarceri at itsqueeze.com 
> <mailto:tarceri at itsqueeze.com>> wrote:
> 
>     Ian and I have been looking at these type of things recently. Ian has
>     started work on a pass to cover this stuff without having to add dozens
>     of these types of opts.
> 
>     https://lists.freedesktop.org/archives/mesa-dev/2018-July/200583.html
> 
> 
> Does said pass work only on logical operations with booleans or also 
> regular bitwise operations?  This patch is for bitwise operations though 
> it naturally works with booleans.

Good point. I replied to this too quickly without thinking too hard. In 
that case we should probably also add these similar opt which I have 
also come across:

    (('ior', ('ior', a, b), a), ('ior', a, b)),
    (('iand', ('iand', a, b), a), ('iand', a, b)),

With those added:

Reviewed-by: Timothy Arceri <tarceri at itsqueeze.com>

> 
> --Jason
> 
>     On 23/07/18 17:36, Jason Ekstrand wrote:
>      > Spotted in a shader in Batman: Arkham City.
>      > ---
>      >   src/compiler/nir/nir_opt_algebraic.py | 2 ++
>      >   1 file changed, 2 insertions(+)
>      >
>      > diff --git a/src/compiler/nir/nir_opt_algebraic.py
>     b/src/compiler/nir/nir_opt_algebraic.py
>      > index ba277fdfd0e..f2007852b21 100644
>      > --- a/src/compiler/nir/nir_opt_algebraic.py
>      > +++ b/src/compiler/nir/nir_opt_algebraic.py
>      > @@ -377,6 +377,8 @@ optimizations = [
>      >      (('ixor', a, a), 0),
>      >      (('ixor', a, 0), a),
>      >      (('inot', ('inot', a)), a),
>      > +   (('ior', ('iand', a, b), b), b),
>      > +   (('iand', ('ior', a, b), b), b),
>      >      # DeMorgan's Laws
>      >      (('iand', ('inot', a), ('inot', b)), ('inot', ('ior',  a, b))),
>      >      (('ior',  ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
>      >
>