From a7f0c57673d2c56c46c4383a7008f525102cd33b Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Tue, 5 Mar 2019 14:54:35 -0800 Subject: [PATCH] nir/algebraic: Eliminate useless fsat() on operand of comparison w/value in (0, 1) MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit v2: Fix copy-and-paste bug in a cmp b vs b cmp a cases. All Gen7+ platforms had similar results. (Ice Lake shown) total instructions in shared programs: 17224337 -> 17224269 (<.01%) instructions in affected programs: 13578 -> 13510 (-0.50%) helped: 68 HURT: 0 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 0.31% max: 3.12% x̄: 0.84% x̃: 0.42% 95% mean confidence interval for instructions value: -1.00 -1.00 95% mean confidence interval for instructions %-change: -1.05% -0.63% Instructions are helped. total cycles in shared programs: 360826090 -> 360825137 (<.01%) cycles in affected programs: 94867 -> 93914 (-1.00%) helped: 58 HURT: 1 helped stats (abs) min: 2 max: 28 x̄: 17.74 x̃: 18 helped stats (rel) min: 0.08% max: 3.17% x̄: 1.39% x̃: 1.22% HURT stats (abs) min: 76 max: 76 x̄: 76.00 x̃: 76 HURT stats (rel) min: 2.86% max: 2.86% x̄: 2.86% x̃: 2.86% 95% mean confidence interval for cycles value: -19.53 -12.78 95% mean confidence interval for cycles %-change: -1.56% -1.08% Cycles are helped. No changes on any other Intel platform. Reviewed-by: Matt Turner Reviewed-by: Thomas Helland --- src/compiler/nir/nir_opt_algebraic.py | 27 +++++++++++++++++++++++++++ src/compiler/nir/nir_search_helpers.h | 30 ++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index 5fc6fd8..79058c0 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -213,6 +213,18 @@ optimizations = [ (('fne', ('fneg', a), -1.0), ('fne', 1.0, a)), (('feq', -1.0, ('fneg', a)), ('feq', a, 1.0)), + (('flt', ('fsat(is_used_once)', a), '#b(is_gt_0_and_lt_1)'), ('flt', a, b)), + (('flt', '#b(is_gt_0_and_lt_1)', ('fsat(is_used_once)', a)), ('flt', b, a)), + (('fge', ('fsat(is_used_once)', a), '#b(is_gt_0_and_lt_1)'), ('fge', a, b)), + (('fge', '#b(is_gt_0_and_lt_1)', ('fsat(is_used_once)', a)), ('fge', b, a)), + (('feq', ('fsat(is_used_once)', a), '#b(is_gt_0_and_lt_1)'), ('feq', a, b)), + (('fne', ('fsat(is_used_once)', a), '#b(is_gt_0_and_lt_1)'), ('fne', a, b)), + + (('fge', ('fsat(is_used_once)', a), 1.0), ('fge', a, 1.0)), + (('flt', ('fsat(is_used_once)', a), 1.0), ('flt', a, 1.0)), + (('fge', 0.0, ('fsat(is_used_once)', a)), ('fge', 0.0, a)), + (('flt', 0.0, ('fsat(is_used_once)', a)), ('flt', 0.0, a)), + # 0.0 >= b2f(a) # b2f(a) <= 0.0 # b2f(a) == 0.0 because b2f(a) can only be 0 or 1 @@ -1136,6 +1148,21 @@ late_optimizations = [ # optimization loop can prevent other optimizations. (('fneg', ('fneg', a)), a), + # These are duplicated from the main optimizations table. The late + # patterns that rearrange expressions like x - .5 < 0 to x < .5 can create + # new patterns like these. The patterns that compare with zero are removed + # because they are unlikely to be created in by anything in + # late_optimizations. + (('flt', ('fsat(is_used_once)', a), '#b(is_gt_0_and_lt_1)'), ('flt', a, b)), + (('flt', '#b(is_gt_0_and_lt_1)', ('fsat(is_used_once)', a)), ('flt', b, a)), + (('fge', ('fsat(is_used_once)', a), '#b(is_gt_0_and_lt_1)'), ('fge', a, b)), + (('fge', '#b(is_gt_0_and_lt_1)', ('fsat(is_used_once)', a)), ('fge', b, a)), + (('feq', ('fsat(is_used_once)', a), '#b(is_gt_0_and_lt_1)'), ('feq', a, b)), + (('fne', ('fsat(is_used_once)', a), '#b(is_gt_0_and_lt_1)'), ('fne', a, b)), + + (('fge', ('fsat(is_used_once)', a), 1.0), ('fge', a, 1.0)), + (('flt', ('fsat(is_used_once)', a), 1.0), ('flt', a, 1.0)), + (('~fge', ('fmin(is_used_once)', ('fadd(is_used_once)', a, b), ('fadd', c, d)), 0.0), ('iand', ('fge', a, ('fneg', b)), ('fge', c, ('fneg', d)))), (('flt', ('fneg', a), ('fneg', b)), ('flt', b, a)), diff --git a/src/compiler/nir/nir_search_helpers.h b/src/compiler/nir/nir_search_helpers.h index dd220df..9e03c61 100644 --- a/src/compiler/nir/nir_search_helpers.h +++ b/src/compiler/nir/nir_search_helpers.h @@ -109,6 +109,36 @@ is_zero_to_one(nir_alu_instr *instr, unsigned src, unsigned num_components, return true; } +/** + * Exclusive compare with (0, 1). + * + * This differs from \c is_zero_to_one because that function tests 0 <= src <= + * 1 while this function tests 0 < src < 1. + */ +static inline bool +is_gt_0_and_lt_1(nir_alu_instr *instr, unsigned src, unsigned num_components, + const uint8_t *swizzle) +{ + /* only constant srcs: */ + if (!nir_src_is_const(instr->src[src].src)) + return false; + + for (unsigned i = 0; i < num_components; i++) { + switch (nir_op_infos[instr->op].input_types[src]) { + case nir_type_float: { + double val = nir_src_comp_as_float(instr->src[src].src, swizzle[i]); + if (isnan(val) || val <= 0.0f || val >= 1.0f) + return false; + break; + } + default: + return false; + } + } + + return true; +} + static inline bool is_not_const_zero(nir_alu_instr *instr, unsigned src, unsigned num_components, const uint8_t *swizzle) -- 2.7.4