src/compiler/nir/nir_lower_mediump_outputs.c

   1 /*
   2  * Copyright (C) 2020 Google, Inc.
   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 FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24 #include "nir.h"
  25 #include "nir_builder.h"
  26
  27 /* Lower mediump outputs to float16, int16, or uint16. */
  28
  29 void
  30 nir_lower_mediump_outputs(nir_shader *nir)
  31 {
  32    nir_function_impl *impl = nir_shader_get_entrypoint(nir);
  33    assert(impl);
  34
  35    /* Get rid of old derefs before we change the types of the variables */
  36    nir_opt_dce(nir);
  37
  38    nir_builder b;
  39    nir_builder_init(&b, impl);
  40
  41    nir_foreach_block_safe (block, impl) {
  42       nir_foreach_instr_safe (instr, block) {
  43          if (instr->type != nir_instr_type_intrinsic)
  44             continue;
  45
  46          nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
  47          if (intr->intrinsic != nir_intrinsic_store_output)
  48             continue;
  49
  50          nir_foreach_variable (var, &nir->outputs) {
  51             if (var->data.driver_location != nir_intrinsic_base(intr))
  52                continue; /* not found yet */
  53
  54             if (var->data.precision != GLSL_PRECISION_MEDIUM &&
  55                 var->data.precision != GLSL_PRECISION_LOW)
  56                break; /* can't lower */
  57
  58             switch (glsl_get_base_type(var->type)) {
  59             case GLSL_TYPE_FLOAT:
  60                var->type = glsl_float16_type(var->type);
  61                b.cursor = nir_before_instr(&intr->instr);
  62                nir_instr_rewrite_src(&intr->instr, &intr->src[0],
  63                      nir_src_for_ssa(nir_f2f16(&b, intr->src[0].ssa)));
  64                nir_intrinsic_set_type(intr, nir_type_float16);
  65                break;
  66
  67             case GLSL_TYPE_INT:
  68                var->type = glsl_int16_type(var->type);
  69                b.cursor = nir_before_instr(&intr->instr);
  70                nir_instr_rewrite_src(&intr->instr, &intr->src[0],
  71                      nir_src_for_ssa(nir_i2i16(&b, intr->src[0].ssa)));
  72                nir_intrinsic_set_type(intr, nir_type_int16);
  73                break;
  74
  75             case GLSL_TYPE_UINT:
  76                var->type = glsl_uint16_type(var->type);
  77                b.cursor = nir_before_instr(&intr->instr);
  78                nir_instr_rewrite_src(&intr->instr, &intr->src[0],
  79                      nir_src_for_ssa(nir_u2u16(&b, intr->src[0].ssa)));
  80                nir_intrinsic_set_type(intr, nir_type_uint16);
  81                break;
  82
  83             default:;
  84             }
  85             break;
  86          }
  87       }
  88    }
  89 }