Module: Mesa Branch: staging/21.2 Commit: 134d11e4c2ef8f955a768981e45882d1a67223e1 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=134d11e4c2ef8f955a768981e45882d1a67223e1
Author: Timur Kristóf <[email protected]> Date: Fri Sep 24 17:23:17 2021 +0200 ac/nir/nggc: Refactor save_reusable_variables. This makes the code more elegant and also fixes the mistake of skipping the blocks that come before loops. Fossil DB changes on Sienna Cichlid with NGGC on: Totals from 1026 (0.80% of 128647) affected shaders: SpillSGPRs: 3817 -> 4035 (+5.71%) CodeSize: 5582856 -> 5538732 (-0.79%); split: -0.89%, +0.10% Instrs: 1106907 -> 1100180 (-0.61%); split: -0.68%, +0.07% Latency: 10084948 -> 10052197 (-0.32%); split: -0.37%, +0.05% InvThroughput: 1567012 -> 1564949 (-0.13%); split: -0.16%, +0.03% SClause: 39789 -> 39075 (-1.79%); split: -2.33%, +0.54% Copies: 95184 -> 96456 (+1.34%); split: -0.19%, +1.53% Branches: 44087 -> 44093 (+0.01%); split: -0.01%, +0.02% PreSGPRs: 47584 -> 51009 (+7.20%); split: -0.61%, +7.80% Fixes: 0bb543bb60f93bea5b1c0ed6382ced49e659273e Signed-off-by: Timur Kristóf <[email protected]> Reviewed-by: Daniel Schürmann <[email protected]> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13001> (cherry picked from commit cb19ebe7baca5f2c4c547094ae3088ad3035be84) --- .pick_status.json | 2 +- src/amd/common/ac_nir_lower_ngg.c | 47 ++++++++++++++++++++++++--------------- 2 files changed, 30 insertions(+), 19 deletions(-) diff --git a/.pick_status.json b/.pick_status.json index e585819ff3f..c05804a3b84 100644 --- a/.pick_status.json +++ b/.pick_status.json @@ -544,7 +544,7 @@ "description": "ac/nir/nggc: Refactor save_reusable_variables.", "nominated": true, "nomination_type": 1, - "resolution": 0, + "resolution": 1, "main_sha": null, "because_sha": "0bb543bb60f93bea5b1c0ed6382ced49e659273e" }, diff --git a/src/amd/common/ac_nir_lower_ngg.c b/src/amd/common/ac_nir_lower_ngg.c index 2d35d65bbec..e33a431affa 100644 --- a/src/amd/common/ac_nir_lower_ngg.c +++ b/src/amd/common/ac_nir_lower_ngg.c @@ -744,31 +744,24 @@ save_reusable_variables(nir_builder *b, lower_ngg_nogs_state *nogs_state) ASSERTED int vec_ok = u_vector_init(&nogs_state->saved_uniforms, sizeof(saved_uniform), 4 * sizeof(saved_uniform)); assert(vec_ok); - unsigned loop_depth = 0; - - nir_foreach_block_safe(block, b->impl) { - /* Check whether we're in a loop. */ - nir_cf_node *next_cf_node = nir_cf_node_next(&block->cf_node); - nir_cf_node *prev_cf_node = nir_cf_node_prev(&block->cf_node); - if (next_cf_node && next_cf_node->type == nir_cf_node_loop) - loop_depth++; - if (prev_cf_node && prev_cf_node->type == nir_cf_node_loop) - loop_depth--; - - /* The following code doesn't make sense in loops, so just skip it then. */ - if (loop_depth) - continue; - + nir_block *block = nir_start_block(b->impl); + while (block) { + /* Process the instructions in the current block. */ nir_foreach_instr_safe(instr, block) { /* Find instructions whose SSA definitions are used by both - * the top and bottom parts of the shader. In this case, it - * makes sense to try to reuse these from the top part. + * the top and bottom parts of the shader (before and after culling). + * Only in this case, it makes sense for the bottom part + * to try to reuse these from the top part. */ if ((instr->pass_flags & nggc_passflag_used_by_both) != nggc_passflag_used_by_both) continue; + /* Determine if we can reuse the current SSA value. + * When vertex compaction is used, it is possible that the same shader invocation + * processes a different vertex in the top and bottom part of the shader. + * Therefore, we only reuse uniform values. + */ nir_ssa_def *ssa = NULL; - switch (instr->type) { case nir_instr_type_alu: { nir_alu_instr *alu = nir_instr_as_alu(instr); @@ -802,6 +795,7 @@ save_reusable_variables(nir_builder *b, lower_ngg_nogs_state *nogs_state) assert(ssa); + /* Determine a suitable type for the SSA value. */ enum glsl_base_type base_type = GLSL_TYPE_UINT; switch (ssa->bit_size) { case 8: base_type = GLSL_TYPE_UINT8; break; @@ -818,6 +812,10 @@ save_reusable_variables(nir_builder *b, lower_ngg_nogs_state *nogs_state) saved_uniform *saved = (saved_uniform *) u_vector_add(&nogs_state->saved_uniforms); assert(saved); + /* Create a new NIR variable where we store the reusable value. + * Then, we reload the variable and replace the uses of the value + * with the reloaded variable. + */ saved->var = nir_local_variable_create(b->impl, t, NULL); saved->ssa = ssa; @@ -828,6 +826,19 @@ save_reusable_variables(nir_builder *b, lower_ngg_nogs_state *nogs_state) nir_ssa_def *reloaded = nir_load_var(b, saved->var); nir_ssa_def_rewrite_uses_after(ssa, reloaded, reloaded->parent_instr); } + + /* Look at the next CF node. */ + nir_cf_node *next_cf_node = nir_cf_node_next(&block->cf_node); + if (next_cf_node) { + /* It makes no sense to try to reuse things from within loops. */ + if (next_cf_node->type == nir_cf_node_loop) { + block = nir_cf_node_cf_tree_next(next_cf_node); + continue; + } + } + + /* Go to the next block. */ + block = nir_block_cf_tree_next(block); } }
