From 391fb32bbef3bdeb7bab78a4d3c5317a0153381e Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Wed, 21 Jan 2015 23:36:01 -0800 Subject: [PATCH] nir: Add algebraic optimizations for simplifying comparisons. 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: 6035392 -> 6025505 (-0.16%) i965 instructions in affected programs: 784980 -> 775093 (-1.26%) helped: 4508 HURT: 2 Signed-off-by: Kenneth Graunke Reviewed-by: Jason Ekstrand Reviewed-by: Matt Turner --- 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 be9487031d2..40722de1ea5 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 -- 2.30.2