src/compiler/nir/nir_opt_shrink_load.c

   1 /*
   2  * Copyright © 2018 Valve Corporation
   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
  26 static bool
  27 opt_shrink_load(nir_intrinsic_instr *instr)
  28 {
  29    bool progress = false;
  30
  31    if (instr->intrinsic == nir_intrinsic_load_push_constant) {
  32       unsigned mask = nir_ssa_def_components_read(&instr->dest.ssa);
  33
  34       if (instr->num_components > util_last_bit(mask)) {
  35          instr->num_components = util_last_bit(mask);
  36          instr->dest.ssa.num_components = instr->num_components;
  37          progress = true;
  38       }
  39    }
  40
  41    return progress;
  42 }
  43
  44 bool
  45 nir_opt_shrink_load(nir_shader *shader)
  46 {
  47    bool progress = false;
  48
  49    nir_foreach_function(function, shader) {
  50       if (!function->impl)
  51          continue;
  52
  53       nir_foreach_block(block, function->impl) {
  54          nir_foreach_instr(instr, block) {
  55             if (instr->type != nir_instr_type_intrinsic)
  56                continue;
  57
  58             progress |= opt_shrink_load(nir_instr_as_intrinsic(instr));
  59          }
  60       }
  61
  62       nir_metadata_preserve(function->impl, nir_metadata_block_index |
  63                                             nir_metadata_dominance);
  64    }
  65
  66    return progress;
  67 }