The first batch removes bonus fnot/inot operations, possibly allowing
other optimizations to better recognize patterns.
The next batch replaces a fadd and constant 0.0 with an fneg - negation
is usually free on GPUs, while addition is not.
total NIR instructions in shared programs: 2020814 -> 2015593 (-0.26%)
NIR instructions in affected programs: 411143 -> 405922 (-1.27%)
helped: 2233
HURT: 214
A few shaders are hurt by a few instructions due to moving neg such
that it has a constant operand, which is then folded, resulting in two
distinct load_consts for x and -x. We can always clean that up later.
total i965 instructions in shared programs: 6035393 -> 6025508 (-0.16%)
i965 instructions in affected programs: 785208 -> 775323 (-1.26%)
helped: 4509
HURT: 2
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
src/glsl/nir/nir_opt_algebraic.py | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
index 58e71e0..dec250b 100644
--- a/src/glsl/nir/nir_opt_algebraic.py
+++ b/src/glsl/nir/nir_opt_algebraic.py
@@ -66,6 +66,15 @@ optimizations = [
(('flrp', a, a, b), a),
(('flrp', 0.0, a, b), ('fmul', a, b)),
(('fadd', ('fmul', a, b), c), ('ffma', a, b, c)),
+ # Comparison simplifications
+ (('inot', ('flt', a, b)), ('fge', a, b)),
+ (('inot', ('fge', a, b)), ('flt', a, b)),
+ (('inot', ('ilt', a, b)), ('ige', a, b)),
+ (('inot', ('ige', a, b)), ('ilt', a, b)),
+ (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
+ (('fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
+ (('feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
+ (('fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
(('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
(('fmin', ('fmax', a, 1.0), 0.0), ('fsat', a)),
# Logical and bit operations
--
2.2.2