src/compiler/nir/nir_opt_move_load_ubo.c

   1 /*
   2  * Copyright © 2016 Intel Corporation
   3  * Copyright © 2018 Valve Corporation
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice (including the next
  13  * paragraph) shall be included in all copies or substantial portions of the
  14  * Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22  * IN THE SOFTWARE.
  23  */
  24
  25 #include "nir.h"
  26
  27 /**
  28  * \file nir_opt_move_load_ubo.c
  29  *
  30  * This pass moves load UBO operations just before their first use inside
  31  * the same basic block.
  32  */
  33 static bool
  34 move_load_ubo_source(nir_src *src, nir_block *block, nir_instr *before)
  35 {
  36    if (!src->is_ssa)
  37       return false;
  38
  39    nir_instr *src_instr = src->ssa->parent_instr;
  40
  41    if (src_instr->block == block &&
  42        src_instr->type == nir_instr_type_intrinsic &&
  43        nir_instr_as_intrinsic(src_instr)->intrinsic == nir_intrinsic_load_ubo) {
  44
  45       exec_node_remove(&src_instr->node);
  46
  47       if (before)
  48          exec_node_insert_node_before(&before->node, &src_instr->node);
  49       else
  50          exec_list_push_tail(&block->instr_list, &src_instr->node);
  51
  52       return true;
  53    }
  54    return false;
  55 }
  56
  57 static bool
  58 move_load_ubo_source_cb(nir_src *src, void *data)
  59 {
  60    bool *progress = data;
  61
  62    nir_instr *instr = src->parent_instr;
  63    if (move_load_ubo_source(src, instr->block, instr))
  64       *progress = true;
  65
  66    return true; /* nir_foreach_src should keep going */
  67 }
  68
  69 static bool
  70 move_load_ubo(nir_block *block)
  71 {
  72    bool progress = false;
  73
  74    nir_if *iff = nir_block_get_following_if(block);
  75    if (iff) {
  76       progress |= move_load_ubo_source(&iff->condition, block, NULL);
  77    }
  78
  79    nir_foreach_instr_reverse(instr, block) {
  80
  81       if (instr->type == nir_instr_type_phi) {
  82          /* We're going backwards so everything else is a phi too */
  83       } else if (instr->type == nir_instr_type_alu) {
  84          nir_alu_instr *alu = nir_instr_as_alu(instr);
  85
  86          for (int i = nir_op_infos[alu->op].num_inputs - 1; i >= 0; i--) {
  87             progress |= move_load_ubo_source(&alu->src[i].src, block, instr);
  88          }
  89       } else {
  90          nir_foreach_src(instr, move_load_ubo_source_cb, &progress);
  91       }
  92    }
  93
  94    return progress;
  95 }
  96
  97 bool
  98 nir_opt_move_load_ubo(nir_shader *shader)
  99 {
 100    bool progress = false;
 101
 102    nir_foreach_function(func, shader) {
 103       if (!func->impl)
 104          continue;
 105
 106       nir_foreach_block(block, func->impl) {
 107          if (move_load_ubo(block)) {
 108             nir_metadata_preserve(func->impl, nir_metadata_block_index |
 109                                               nir_metadata_dominance |
 110                                               nir_metadata_live_ssa_defs);
 111             progress = true;
 112          }
 113       }
 114    }
 115
 116    return progress;
 117 }