On Mon, Jul 7, 2014 at 6:56 AM, Abdiel Janulgue <abdiel.janul...@linux.intel.com> wrote: > V2 of clamp/saturate optimizations > > This patch series add the plumbing to support the GLSL IR instruction > saturate(). > Previously, saturate is implemented as min/max instructions. Most GPUs, > however, > can probably perform saturate for free. With these changes, we can allow > saturate > to be optimized as a single instruction. > > In addition, the optimization try_emit_saturate was previously used to > optimize > min/max operations to a saturate operation. It didn't work for code such as > min(max(a, b), c) where (b == 0.0 and c < 1.0) and related cases. > With this infrastructure in place, we can optimize those operations easily in > the > do_algebraic pass. > > Changes since v1: > - Only remove the old try_emit_saturate operations after the new > optimizations are > in place. (Matt, Ian) > - Output [min/max](saturate(x),b) instead of saturate([min/max](x,b)) as > suggested > by Ilia Mirkin. > - The change above required some refactoring in the fs/vec4 backend to allow > propagation of certain instructions with saturate flag to SEL. For other > instructions, > we don't propagate saturate instructions, similar to the previous > behaviour. > > Results: > > helped: shaders/0ad/9.shader_test fs16: 38 -> 37 (-2.63%) > helped: shaders/0ad/9.shader_test fs8: 38 -> 37 (-2.63%) > helped: shaders/gst-gl-tunnel.frag fs16: 65 -> 64 (-1.54%) > helped: shaders/gst-gl-tunnel.frag fs8: 65 -> 64 (-1.54%) > > total instructions in shared programs: 41595 -> 41591 (-0.01%) > instructions in affected programs: 206 -> 202 (-1.94%)
Off-list: You'll need to run this with the closed shader-db branch on teamforge: https://git-amr-2.devtools.intel.com/gerrit/gitweb?p=otc_gen_graphics-shader-db.git There are a lot of instruction count regressions that'll need to be investigated. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
