From 6b3670ae8045c4469dc918068a2f2c1c90a64ddf Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Wed, 1 Aug 2018 19:46:26 -0700 Subject: [PATCH] nir: Transform -fabs(a) >= 0 to a == 0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit All Gen platforms had pretty similar results. (Skylake shown) total instructions in shared programs: 14276964 -> 14276961 (<.01%) instructions in affected programs: 411 -> 408 (-0.73%) helped: 3 HURT: 0 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 0.47% max: 1.96% x̄: 1.04% x̃: 0.68% total cycles in shared programs: 532577062 -> 532577068 (<.01%) cycles in affected programs: 1093 -> 1099 (0.55%) helped: 1 HURT: 1 helped stats (abs) min: 16 max: 16 x̄: 16.00 x̃: 16 helped stats (rel) min: 7.77% max: 7.77% x̄: 7.77% x̃: 7.77% HURT stats (abs) min: 22 max: 22 x̄: 22.00 x̃: 22 HURT stats (rel) min: 2.48% max: 2.48% x̄: 2.48% x̃: 2.48% Signed-off-by: Ian Romanick Reviewed-by: Thomas Helland --- src/compiler/nir/nir_opt_algebraic.py | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index 5ba469f..fd26065 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -235,6 +235,15 @@ optimizations = [ # fabs(a) > 0.0 (('~flt', ('fneg', ('fabs', a)), 0.0), ('fne', a, 0.0)), + # 0.0 >= fabs(a) + # 0.0 == fabs(a) because fabs(a) must be >= 0 + # 0.0 == a + (('fge', 0.0, ('fabs', a)), ('feq', a, 0.0)), + + # -fabs(a) >= 0.0 + # 0.0 >= fabs(a) + (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)), + (('fmax', ('b2f(is_used_once)', a), ('b2f', b)), ('b2f', ('ior', a, b))), (('fmax', ('fneg(is_used_once)', ('b2f(is_used_once)', a)), ('fneg', ('b2f', b))), ('fneg', ('b2f', ('ior', a, b)))), (('fmin', ('b2f(is_used_once)', a), ('b2f', b)), ('b2f', ('iand', a, b))), -- 2.7.4