nir: add an optimization to remove useless phi nodes

Graphics / Mesa 3D Graphics Library / Mesa - Connor Abbott [gmail.com] - 3 February 2015 15:00 EST

This removes phi nodes whose sources all point to the same thing.

Shader-db results:

total NIR instructions in shared programs: 2045293 -> 2041209 (-0.20%) NIR instructions in affected programs: 126564 -> 122480 (-3.23%) helped: 615 HURT: 0

total FS instructions in shared programs: 4321840 -> 4320392 (-0.03%) FS instructions in affected programs: 24622 -> 23174 (-5.88%) helped: 138 HURT: 0

a135f34 nir: add an optimization to remove useless phi nodes
src/glsl/Makefile.sources | 1 +
src/glsl/nir/nir.h | 2 +
src/glsl/nir/nir_opt_remove_phis.c | 109 ++++++++++++++++++++++++++++++++++++
3 files changed, 112 insertions(+)

Upstream: cgit.freedesktop.org


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