src/gallium/drivers/lima/ir/lima_nir_duplicate_consts.c

   1 /*
   2  * Copyright (c) 2020 Lima Project
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #include "nir.h"
  25 #include "nir_builder.h"
  26 #include "lima_ir.h"
  27
  28 static bool
  29 lima_nir_duplicate_load_const(nir_builder *b, nir_load_const_instr *load)
  30 {
  31    nir_load_const_instr *last_dupl = NULL;
  32    nir_instr *last_parent_instr = NULL;
  33
  34    nir_foreach_use_safe(use_src, &load->def) {
  35       nir_load_const_instr *dupl;
  36
  37       if (last_parent_instr != use_src->parent_instr) {
  38          /* if ssa use, clone for the target block */
  39          b->cursor = nir_before_instr(use_src->parent_instr);
  40
  41          dupl = nir_load_const_instr_create(b->shader, load->def.num_components,
  42                                             load->def.bit_size);
  43          memcpy(&dupl->value, &load->value, sizeof(*load->value) * load->def.num_components);
  44
  45          dupl->instr.pass_flags = 1;
  46          nir_builder_instr_insert(b, &dupl->instr);
  47       }
  48       else {
  49          dupl = last_dupl;
  50       }
  51
  52       nir_instr_rewrite_src(use_src->parent_instr, use_src, nir_src_for_ssa(&dupl->def));
  53       last_parent_instr = use_src->parent_instr;
  54       last_dupl = dupl;
  55    }
  56
  57    last_dupl = NULL;
  58    last_parent_instr = NULL;
  59
  60    nir_foreach_if_use_safe(use_src, &load->def) {
  61       nir_load_const_instr *dupl;
  62
  63       if (last_parent_instr != use_src->parent_instr) {
  64          /* if 'if use', clone where it is */
  65          b->cursor = nir_before_instr(&load->instr);
  66
  67          dupl = nir_load_const_instr_create(b->shader, load->def.num_components,
  68                                             load->def.bit_size);
  69          memcpy(&dupl->value, &load->value, sizeof(*load->value) * load->def.num_components);
  70
  71          dupl->instr.pass_flags = 1;
  72          nir_builder_instr_insert(b, &dupl->instr);
  73       }
  74       else {
  75          dupl = last_dupl;
  76       }
  77
  78       nir_if_rewrite_condition(use_src->parent_if, nir_src_for_ssa(&dupl->def));
  79       last_parent_instr = use_src->parent_instr;
  80       last_dupl = dupl;
  81    }
  82
  83    nir_instr_remove(&load->instr);
  84    return true;
  85 }
  86
  87 static void
  88 lima_nir_duplicate_load_consts_impl(nir_shader *shader, nir_function_impl *impl)
  89 {
  90    nir_builder builder;
  91    nir_builder_init(&builder, impl);
  92
  93    nir_foreach_block(block, impl) {
  94       nir_foreach_instr(instr, block) {
  95          instr->pass_flags = 0;
  96       }
  97
  98       nir_foreach_instr_safe(instr, block) {
  99          if (instr->type != nir_instr_type_load_const)
 100             continue;
 101
 102          nir_load_const_instr *load = nir_instr_as_load_const(instr);
 103
 104          if (load->instr.pass_flags)
 105             continue;
 106
 107          lima_nir_duplicate_load_const(&builder, load);
 108       }
 109    }
 110
 111    nir_metadata_preserve(impl, nir_metadata_block_index |
 112                                nir_metadata_dominance);
 113 }
 114
 115 /* Duplicate load consts for every user.
 116  * Helps by utilizing the load const instruction slots that would
 117  * otherwise stay empty, and reduces register pressure. */
 118 void
 119 lima_nir_duplicate_load_consts(nir_shader *shader)
 120 {
 121    nir_foreach_function(function, shader) {
 122       if (function->impl) {
 123          lima_nir_duplicate_load_consts_impl(shader, function->impl);
 124       }
 125    }
 126 }