src/compiler/nir/nir_lower_io_to_scalar.c

   1 /*
   2  * Copyright © 2016 Broadcom
   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
  27 /** @file nir_lower_io_to_scalar.c
  28  *
  29  * Replaces nir_load_input/nir_store_output operations with num_components !=
  30  * 1 with individual per-channel operations.
  31  */
  32
  33 static void
  34 lower_load_input_to_scalar(nir_builder *b, nir_intrinsic_instr *intr)
  35 {
  36    b->cursor = nir_before_instr(&intr->instr);
  37
  38    assert(intr->dest.is_ssa);
  39
  40    nir_ssa_def *loads[4];
  41
  42    for (unsigned i = 0; i < intr->num_components; i++) {
  43       nir_intrinsic_instr *chan_intr =
  44          nir_intrinsic_instr_create(b->shader, intr->intrinsic);
  45       nir_ssa_dest_init(&chan_intr->instr, &chan_intr->dest,
  46                         1, intr->dest.ssa.bit_size, NULL);
  47       chan_intr->num_components = 1;
  48
  49       nir_intrinsic_set_base(chan_intr, nir_intrinsic_base(intr));
  50       nir_intrinsic_set_component(chan_intr, nir_intrinsic_component(intr) + i);
  51       /* offset */
  52       chan_intr->src[0] = intr->src[0];
  53
  54       nir_builder_instr_insert(b, &chan_intr->instr);
  55
  56       loads[i] = &chan_intr->dest.ssa;
  57    }
  58
  59    nir_ssa_def_rewrite_uses(&intr->dest.ssa,
  60                             nir_src_for_ssa(nir_vec(b, loads,
  61                                                     intr->num_components)));
  62    nir_instr_remove(&intr->instr);
  63 }
  64
  65 static void
  66 lower_store_output_to_scalar(nir_builder *b, nir_intrinsic_instr *intr)
  67 {
  68    b->cursor = nir_before_instr(&intr->instr);
  69
  70    nir_ssa_def *value = nir_ssa_for_src(b, intr->src[0], intr->num_components);
  71
  72    for (unsigned i = 0; i < intr->num_components; i++) {
  73       if (!(nir_intrinsic_write_mask(intr) & (1 << i)))
  74          continue;
  75
  76       nir_intrinsic_instr *chan_intr =
  77          nir_intrinsic_instr_create(b->shader, intr->intrinsic);
  78       chan_intr->num_components = 1;
  79
  80       nir_intrinsic_set_base(chan_intr, nir_intrinsic_base(intr));
  81       nir_intrinsic_set_write_mask(chan_intr, 0x1);
  82       nir_intrinsic_set_component(chan_intr, nir_intrinsic_component(intr) + i);
  83
  84       /* value */
  85       chan_intr->src[0] = nir_src_for_ssa(nir_channel(b, value, i));
  86       /* offset */
  87       chan_intr->src[1] = intr->src[1];
  88
  89       nir_builder_instr_insert(b, &chan_intr->instr);
  90    }
  91
  92    nir_instr_remove(&intr->instr);
  93 }
  94
  95 void
  96 nir_lower_io_to_scalar(nir_shader *shader, nir_variable_mode mask)
  97 {
  98    nir_foreach_function(function, shader) {
  99       if (function->impl) {
 100          nir_builder b;
 101          nir_builder_init(&b, function->impl);
 102
 103          nir_foreach_block(block, function->impl) {
 104             nir_foreach_instr_safe(instr, block) {
 105                if (instr->type != nir_instr_type_intrinsic)
 106                   continue;
 107
 108                nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
 109
 110                if (intr->num_components == 1)
 111                   continue;
 112
 113                switch (intr->intrinsic) {
 114                case nir_intrinsic_load_input:
 115                   if (mask & nir_var_shader_in)
 116                      lower_load_input_to_scalar(&b, intr);
 117                   break;
 118                case nir_intrinsic_store_output:
 119                   if (mask & nir_var_shader_out)
 120                      lower_store_output_to_scalar(&b, intr);
 121                   break;
 122                default:
 123                   break;
 124                }
 125             }
 126          }
 127       }
 128    }
 129 }