From 69e55d9c1b473dd5577d0fe48998421136860598 Mon Sep 17 00:00:00 2001 From: Rhys Perry Date: Wed, 14 Dec 2022 17:50:24 +0000 Subject: [PATCH] ac/nir: fix ngg culling on gfx11 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This subtraction can underflow. If subgroup_id*wave_size is larger than num_live_vertices_in_workgroup, num_es_threads_var should be zero. fossil-db (gfx1100, nggc): Totals from 41388 (30.75% of 134574) affected shaders: Instrs: 25700772 -> 25783544 (+0.32%) CodeSize: 126950072 -> 127281160 (+0.26%) Latency: 92809233 -> 92849566 (+0.04%); split: -0.00%, +0.04% InvThroughput: 9526675 -> 9542194 (+0.16%) Copies: 2031078 -> 2031074 (-0.00%) Signed-off-by: Rhys Perry Reviewed-by: Qiang Yu Reviewed-by: Timur Kristóf Reviewed-by: Marek Olšák Part-of: --- src/amd/common/ac_nir_lower_ngg.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/amd/common/ac_nir_lower_ngg.c b/src/amd/common/ac_nir_lower_ngg.c index f6643b228d3..75519b84b61 100644 --- a/src/amd/common/ac_nir_lower_ngg.c +++ b/src/amd/common/ac_nir_lower_ngg.c @@ -1547,8 +1547,8 @@ add_deferred_attribute_culling(nir_builder *b, nir_cf_list *original_extracted_c nir_ssa_def *num_live_vertices_in_wave = num_live_vertices_in_workgroup; if (nogs_state->max_num_waves > 1) { num_live_vertices_in_wave = - nir_isub(b, num_live_vertices_in_wave, - nir_imul_imm(b, nir_load_subgroup_id(b), nogs_state->options->wave_size)); + nir_usub_sat(b, num_live_vertices_in_wave, + nir_imul_imm(b, nir_load_subgroup_id(b), nogs_state->options->wave_size)); num_live_vertices_in_wave = nir_umin(b, num_live_vertices_in_wave, nir_imm_int(b, nogs_state->options->wave_size)); }