On 12/15/2015 09:28 AM, Kristian Høgsberg Kristensen wrote:
> This optimizes a + b - b to just a. Modest shader-db results (BDW):
>
> total instructions in shared programs: 7842452 -> 7841862 (-0.01%)
> instructions in affected programs: 61938 -> 61348 (-0.95%)
> total loops in shared programs: 2131 -> 2131 (0.00%)
> helped: 263
> HURT: 0
> GAINED: 0
> LOST: 0
>
In HSW, I get these shader-db results:
total instructions in shared programs: 6257265 -> 6256788 (-0.01%)
instructions in affected programs: 46601 -> 46124 (-1.02%)
helped: 218
HURT: 0
total cycles in shared programs: 56010026 -> 56007760 (-0.00%)
cycles in affected programs: 1048392 -> 1046126 (-0.22%)
helped: 199
HURT: 154
total loops in shared programs: 1979 -> 1979 (0.00%)
loops in affected programs: 0 -> 0
helped: 0
HURT: 0
LOST: 0
GAINED: 0
I wonder where those cycle HURTs come from. In any case, the net result
is positive.
Patch is:
Reviewed-by: Eduardo Lima Mitev <el...@igalia.com>
> but the optimization turns
>
> gl_VertexID - gl_BaseVertexARB
>
> into just a reference to SYSTEM_VALUE_VERTEX_ID_ZERO_BASE, which the
> i965 hardware supports natively. That means we can avoid using the
> internal vertex buffer for gl_BaseVertexARB in this case.
> ---
> src/glsl/nir/nir_opt_algebraic.py | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/src/glsl/nir/nir_opt_algebraic.py
> b/src/glsl/nir/nir_opt_algebraic.py
> index cb715c0..1fdad3d 100644
> --- a/src/glsl/nir/nir_opt_algebraic.py
> +++ b/src/glsl/nir/nir_opt_algebraic.py
> @@ -62,6 +62,10 @@ optimizations = [
> (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
> (('fadd', ('fneg', a), a), 0.0),
> (('iadd', ('ineg', a), a), 0),
> + (('iadd', ('ineg', a), ('iadd', a, b)), b),
> + (('iadd', a, ('iadd', ('ineg', a), b)), b),
> + (('fadd', ('fneg', a), ('fadd', a, b)), b),
> + (('fadd', a, ('fadd', ('fneg', a), b)), b),
> (('fmul', a, 0.0), 0.0),
> (('imul', a, 0), 0),
> (('umul_unorm_4x8', a, 0), 0),
>
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
