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

[Jason Ekstrand]

On Mon, Jul 23, 2018 at 1:08 AM Timothy Arceri <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.

--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))),
> >
>
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