From ba203a3cd7707a4c2328520281c986801cfb5733 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Tue, 7 May 2019 09:22:27 -0700 Subject: [PATCH] =?utf8?q?nir/flrp:=20Fix=20typo=20on=20the=20flrp(=C2=B11?= =?utf8?q?,=20b,=20c)=20path?= MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit After Samuel reported the bisect, I was able to find the bug by inspection. Good thing for well-named varibles. :) Unfortunately, this undoes almost all of the benefit of the original patch. Ice Lake total instructions in shared programs: 17183159 -> 17218166 (0.20%) instructions in affected programs: 1308722 -> 1343729 (2.67%) helped: 98 HURT: 4746 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 0.47% max: 2.70% x̄: 0.60% x̃: 0.57% HURT stats (abs) min: 1 max: 691 x̄: 7.40 x̃: 8 HURT stats (rel) min: 0.10% max: 700.00% x̄: 5.82% x̃: 2.83% 95% mean confidence interval for instructions value: 6.82 7.64 95% mean confidence interval for instructions %-change: 5.22% 6.15% Instructions are HURT. total cycles in shared programs: 360705959 -> 360853522 (0.04%) cycles in affected programs: 10754380 -> 10901943 (1.37%) helped: 1594 HURT: 3331 helped stats (abs) min: 1 max: 1896 x̄: 119.81 x̃: 60 helped stats (rel) min: <.01% max: 35.48% x̄: 5.06% x̃: 3.64% HURT stats (abs) min: 1 max: 10208 x̄: 101.63 x̃: 38 HURT stats (rel) min: 0.01% max: 878.95% x̄: 9.01% x̃: 2.78% 95% mean confidence interval for cycles value: 21.11 38.81 95% mean confidence interval for cycles %-change: 3.76% 5.15% Cycles are HURT. total spills in shared programs: 12158 -> 12355 (1.62%) spills in affected programs: 98 -> 295 (201.02%) helped: 1 HURT: 2 total fills in shared programs: 25204 -> 25398 (0.77%) fills in affected programs: 94 -> 288 (206.38%) helped: 0 HURT: 3 LOST: 15 GAINED: 8 Iron Lake total instructions in shared programs: 8121430 -> 8166733 (0.56%) instructions in affected programs: 1148353 -> 1193656 (3.95%) helped: 2 HURT: 4046 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 1.85% max: 1.92% x̄: 1.89% x̃: 1.89% HURT stats (abs) min: 1 max: 43 x̄: 11.20 x̃: 11 HURT stats (rel) min: 0.20% max: 716.67% x̄: 7.40% x̃: 3.87% 95% mean confidence interval for instructions value: 11.02 11.37 95% mean confidence interval for instructions %-change: 6.84% 7.94% Instructions are HURT. total cycles in shared programs: 188376326 -> 188601568 (0.12%) cycles in affected programs: 27416674 -> 27641916 (0.82%) helped: 68 HURT: 3947 helped stats (abs) min: 2 max: 222 x̄: 13.88 x̃: 6 helped stats (rel) min: <.01% max: 1.28% x̄: 0.15% x̃: 0.01% HURT stats (abs) min: 2 max: 670 x̄: 57.31 x̃: 64 HURT stats (rel) min: <.01% max: 1811.11% x̄: 4.11% x̃: 1.09% 95% mean confidence interval for cycles value: 55.01 57.20 95% mean confidence interval for cycles %-change: 2.88% 5.19% Cycles are HURT. LOST: 35 GAINED: 3 GM45 total instructions in shared programs: 4979794 -> 5003551 (0.48%) instructions in affected programs: 635174 -> 658931 (3.74%) helped: 1 HURT: 2142 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 1.85% max: 1.85% x̄: 1.85% x̃: 1.85% HURT stats (abs) min: 1 max: 43 x̄: 11.09 x̃: 11 HURT stats (rel) min: 0.20% max: 716.67% x̄: 7.00% x̃: 3.53% 95% mean confidence interval for instructions value: 10.85 11.33 95% mean confidence interval for instructions %-change: 6.25% 7.74% Instructions are HURT. total cycles in shared programs: 128519586 -> 128654990 (0.11%) cycles in affected programs: 17635304 -> 17770708 (0.77%) helped: 46 HURT: 2088 helped stats (abs) min: 4 max: 220 x̄: 18.13 x̃: 6 helped stats (rel) min: <.01% max: 1.28% x̄: 0.15% x̃: 0.01% HURT stats (abs) min: 2 max: 670 x̄: 65.25 x̃: 66 HURT stats (rel) min: <.01% max: 1464.29% x̄: 4.05% x̃: 0.99% 95% mean confidence interval for cycles value: 61.75 65.15 95% mean confidence interval for cycles %-change: 2.58% 5.34% Cycles are HURT. LOST: 38 GAINED: 38 Fixes: 5b908db604b ("nir/flrp: Lower flrp(±1, b, c) and flrp(a, ±1, c) differently") Reported-by: Samuel Pitoiset Reviewed-by: Matt Turner Reviewed-by: Samuel Pitoiset --- src/compiler/nir/nir_lower_flrp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/compiler/nir/nir_lower_flrp.c b/src/compiler/nir/nir_lower_flrp.c index 31969a61c79..41342403d48 100644 --- a/src/compiler/nir/nir_lower_flrp.c +++ b/src/compiler/nir/nir_lower_flrp.c @@ -172,6 +172,8 @@ replace_with_fast(struct nir_builder *bld, struct u_vector *dead_flrp, /** * Replace flrp(a, b, c) with (b*c ± c) + a + * + * \note: This only works if a = ±1. */ static void replace_with_expanded_ffma_and_add(struct nir_builder *bld, @@ -182,7 +184,7 @@ replace_with_expanded_ffma_and_add(struct nir_builder *bld, nir_ssa_def *const b = nir_ssa_for_alu_src(bld, alu, 1); nir_ssa_def *const c = nir_ssa_for_alu_src(bld, alu, 2); - nir_ssa_def *const b_times_c = nir_fadd(bld, b, c); + nir_ssa_def *const b_times_c = nir_fmul(bld, b, c); nir_instr_as_alu(b_times_c->parent_instr)->exact = alu->exact; nir_ssa_def *inner_sum; -- 2.30.2