From a7ff1bb5b9a78cf57073b5e2e136daf0c85078d6 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Daniel=20Sch=C3=BCrmann?= Date: Thu, 24 Oct 2019 11:38:37 +0200 Subject: [PATCH] aco: simplify calculation of target register pressure when spilling Reviewed-by: Rhys Perry --- src/amd/compiler/aco_spill.cpp | 51 ++++++++-------------------------- 1 file changed, 12 insertions(+), 39 deletions(-) diff --git a/src/amd/compiler/aco_spill.cpp b/src/amd/compiler/aco_spill.cpp index 60a99aa9247..b684d560abf 100644 --- a/src/amd/compiler/aco_spill.cpp +++ b/src/amd/compiler/aco_spill.cpp @@ -1592,54 +1592,27 @@ void spill(Program* program, live& live_vars, const struct radv_nir_compiler_opt program->config->spilled_vgprs = 0; program->config->spilled_sgprs = 0; - /* no spilling when wave count is already high */ - if (program->num_waves >= 6) + /* no spilling when register pressure is low enough */ + if (program->num_waves > 0) return; /* lower to CSSA before spilling to ensure correctness w.r.t. phis */ lower_to_cssa(program, live_vars, options); - /* else, we check if we can improve things a bit */ - /* calculate target register demand */ - RegisterDemand max_reg_demand; - for (Block& block : program->blocks) { - max_reg_demand.update(block.register_demand); - } - - RegisterDemand target_pressure = {256, int16_t(program->sgpr_limit)}; - unsigned num_waves = 1; - int spills_to_vgpr = (max_reg_demand.sgpr - program->sgpr_limit + 63) / 64; - - /* test if it possible to increase occupancy with little spilling */ - for (unsigned num_waves_next = 2; num_waves_next <= program->max_waves; num_waves_next++) { - RegisterDemand target_pressure_next = {int16_t((256 / num_waves_next) & ~3), - int16_t(get_addr_sgpr_from_waves(program, num_waves_next))}; - - /* Currently no vgpr spilling supported. - * Spill as many sgprs as necessary to not hinder occupancy */ - if (max_reg_demand.vgpr > target_pressure_next.vgpr) - break; - /* check that we have enough free vgprs to spill sgprs to */ - if (max_reg_demand.sgpr > target_pressure_next.sgpr) { - /* add some buffer in case graph coloring is not perfect ... */ - const int spills_to_vgpr_next = (max_reg_demand.sgpr - target_pressure_next.sgpr + 63 + 32) / 64; - if (spills_to_vgpr_next + max_reg_demand.vgpr > target_pressure_next.vgpr) - break; - spills_to_vgpr = spills_to_vgpr_next; - } + RegisterDemand register_target = program->max_reg_demand; + if (register_target.sgpr > program->sgpr_limit) + register_target.vgpr += (register_target.sgpr - program->sgpr_limit + 63 + 32) / 64; + register_target.sgpr = program->sgpr_limit; - target_pressure = target_pressure_next; - num_waves = num_waves_next; - } + if (register_target.vgpr > program->vgpr_limit) + register_target.sgpr = program->sgpr_limit - 5; + register_target.vgpr = program->vgpr_limit - (register_target.vgpr - program->max_reg_demand.vgpr); - assert(max_reg_demand.vgpr <= target_pressure.vgpr && "VGPR spilling not yet supported."); - /* nothing to do */ - if (num_waves == program->num_waves) - return; + int spills_to_vgpr = (program->max_reg_demand.sgpr - register_target.sgpr + 63 + 32) / 64; /* initialize ctx */ - spill_ctx ctx(target_pressure, program, live_vars.register_demand); + spill_ctx ctx(register_target, program, live_vars.register_demand); compute_global_next_uses(ctx, live_vars.live_out); get_rematerialize_info(ctx); @@ -1653,7 +1626,7 @@ void spill(Program* program, live& live_vars, const struct radv_nir_compiler_opt /* update live variable information */ live_vars = live_var_analysis(program, options); - assert(program->num_waves >= num_waves); + assert(program->num_waves >= 0); } } -- 2.30.2