nir: Optimize (a*b)+(a*c) -> a*(b+c)

Shader-db i965 instructions:
total instructions in shared programs: 1715894 -> 1710802 (-0.30%)
instructions in affected programs:     443080 -> 437988 (-1.15%)
helped:                                1502
HURT:                                  13
GAINED:                                4
LOST:                                  4

Shader-db NIR instructions:
total instructions in shared programs: 607710 -> 606187 (-0.25%)
instructions in affected programs:     208285 -> 206762 (-0.73%)
helped:                                769
HURT:                                  8
GAINED:                                0
LOST:                                  0

Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Signed-off-by: Thomas Helland <thomashelland90@gmail.com>

diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
index 7bf6431345a46198784fa7bc5e814351ed07891b..688ceff8c92e0e0ee20a0e6441695115a56eec8e 100644 (file)
--- a/src/glsl/nir/nir_opt_algebraic.py
+++ b/src/glsl/nir/nir_opt_algebraic.py
@@ -56,6 +56,8 @@ optimizations = [
    (('iabs', ('ineg', a)), ('iabs', a)),
    (('fadd', a, 0.0), a),
    (('iadd', a, 0), a),
+   (('fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
+   (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
    (('fmul', a, 0.0), 0.0),
    (('imul', a, 0), 0),
    (('fmul', a, 1.0), a),