From eae19f5f19f57ed669c042fea4f8eb40b8a9e23a Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Mon, 3 Dec 2018 16:30:44 -0800 Subject: [PATCH] nir/algebraic: Replace i2b used by bcsel or if-statement with comparison MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit All of the helped shaders are in Deus Ex. I looked at a couple shaders, and they have a pattern like: vec1 32 ssa_373 = i2b32 ssa_345.w vec1 32 ssa_374 = bcsel ssa_373, ssa_20, ssa_0 ... vec1 32 ssa_377 = ine ssa_345.w, ssa_0 if ssa_377 { ... vec1 32 ssa_416 = i2b32 ssa_385.w vec1 32 ssa_417 = bcsel ssa_416, ssa_386, ssa_374 ... } The massive help occurs because the i2b32 is removed, then other passes determine that ssa_374 must be ssa_20 inside the if-statement allowing the first bcsel to also be deleted. v2: Rebase on 1-bit Boolean changes. v3: Fix i2b32 vs ine problem in if-statement replacement. Noticed by Bas. Skylake total instructions in shared programs: 15241394 -> 15186287 (-0.36%) instructions in affected programs: 890583 -> 835476 (-6.19%) helped: 355 HURT: 0 helped stats (abs) min: 1 max: 497 x̄: 155.23 x̃: 149 helped stats (rel) min: 0.09% max: 16.49% x̄: 6.10% x̃: 6.59% 95% mean confidence interval for instructions value: -165.07 -145.39 95% mean confidence interval for instructions %-change: -6.42% -5.77% Instructions are helped. total cycles in shared programs: 373846583 -> 371023357 (-0.76%) cycles in affected programs: 118972102 -> 116148876 (-2.37%) helped: 343 HURT: 14 helped stats (abs) min: 45 max: 118284 x̄: 8332.32 x̃: 6089 helped stats (rel) min: 0.03% max: 38.19% x̄: 2.48% x̃: 1.77% HURT stats (abs) min: 120 max: 4126 x̄: 2482.79 x̃: 3019 HURT stats (rel) min: 0.16% max: 17.37% x̄: 2.13% x̃: 1.11% 95% mean confidence interval for cycles value: -8723.28 -7093.12 95% mean confidence interval for cycles %-change: -2.57% -2.02% Cycles are helped. total spills in shared programs: 32401 -> 23465 (-27.58%) spills in affected programs: 24457 -> 15521 (-36.54%) helped: 343 HURT: 0 total fills in shared programs: 37866 -> 31765 (-16.11%) fills in affected programs: 18889 -> 12788 (-32.30%) helped: 343 HURT: 0 Broadwell and Haswell had similar results. (Haswell shown) Haswell total instructions in shared programs: 13764783 -> 13750679 (-0.10%) instructions in affected programs: 1176256 -> 1162152 (-1.20%) helped: 334 HURT: 21 helped stats (abs) min: 1 max: 358 x̄: 42.59 x̃: 47 helped stats (rel) min: 0.09% max: 11.81% x̄: 1.30% x̃: 1.37% HURT stats (abs) min: 1 max: 61 x̄: 5.76 x̃: 1 HURT stats (rel) min: 0.03% max: 1.84% x̄: 0.17% x̃: 0.03% 95% mean confidence interval for instructions value: -43.99 -35.47 95% mean confidence interval for instructions %-change: -1.35% -1.08% Instructions are helped. total cycles in shared programs: 386511910 -> 385402528 (-0.29%) cycles in affected programs: 143831110 -> 142721728 (-0.77%) helped: 327 HURT: 39 helped stats (abs) min: 16 max: 25219 x̄: 3519.74 x̃: 3570 helped stats (rel) min: <.01% max: 10.26% x̄: 0.95% x̃: 0.96% HURT stats (abs) min: 16 max: 4881 x̄: 1065.95 x̃: 997 HURT stats (rel) min: <.01% max: 16.67% x̄: 0.70% x̃: 0.24% 95% mean confidence interval for cycles value: -3375.59 -2686.60 95% mean confidence interval for cycles %-change: -0.92% -0.64% Cycles are helped. total spills in shared programs: 100480 -> 97846 (-2.62%) spills in affected programs: 84702 -> 82068 (-3.11%) helped: 316 HURT: 21 total fills in shared programs: 96877 -> 94369 (-2.59%) fills in affected programs: 69167 -> 66659 (-3.63%) helped: 316 HURT: 9 No changes on Ivy Bridge or earlier platforms. Reviewed-by: Kenneth Graunke --- src/compiler/nir/nir_opt_algebraic.py | 3 +++ src/compiler/nir/nir_search_helpers.h | 6 ++++++ 2 files changed, 9 insertions(+) diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index 4d01f110f80..a2079140900 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -298,6 +298,7 @@ optimizations = [ (('~bcsel', ('flt', a, b), b, a), ('fmax', a, b)), (('~bcsel', ('fge', a, b), b, a), ('fmin', a, b)), (('~bcsel', ('fge', b, a), b, a), ('fmax', a, b)), + (('bcsel', ('i2b', a), b, c), ('bcsel', ('ine', a, 0), b, c)), (('bcsel', ('inot', a), b, c), ('bcsel', a, c, b)), (('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)), (('bcsel', a, b, ('bcsel', a, c, d)), ('bcsel', a, b, d)), @@ -519,6 +520,8 @@ optimizations = [ (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'), (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'), # Boolean simplifications + (('i2b32(is_used_by_if)', a), ('ine32', a, 0)), + (('i2b1(is_used_by_if)', a), ('ine', a, 0)), (('ieq', 'a@bool', True), a), (('ine(is_not_used_by_if)', 'a@bool', True), ('inot', a)), (('ine', 'a@bool', False), a), diff --git a/src/compiler/nir/nir_search_helpers.h b/src/compiler/nir/nir_search_helpers.h index 89f1cba5c52..456de81e175 100644 --- a/src/compiler/nir/nir_search_helpers.h +++ b/src/compiler/nir/nir_search_helpers.h @@ -154,6 +154,12 @@ is_used_once(nir_alu_instr *instr) return true; } +static inline bool +is_used_by_if(nir_alu_instr *instr) +{ + return !list_empty(&instr->dest.dest.ssa.if_uses); +} + static inline bool is_not_used_by_if(nir_alu_instr *instr) { -- 2.30.2