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 FS outputs to fp16 */
  28
  29 static bool
  30 lower_output_var(nir_shader *nir, int location)
  31 {
  32    nir_foreach_variable (var, &nir->outputs) {
  33       if (var->data.driver_location == location &&
  34             ((var->data.precision == GLSL_PRECISION_MEDIUM) ||
  35              (var->data.precision == GLSL_PRECISION_LOW))) {
  36          if (glsl_get_base_type(var->type) == GLSL_TYPE_FLOAT)
  37             var->type = glsl_float16_type(var->type);
  38
  39          return glsl_get_base_type(var->type) == GLSL_TYPE_FLOAT16;
  40       }
  41    }
  42
  43    return false;
  44 }
  45
  46 void
  47 nir_lower_mediump_outputs(nir_shader *nir)
  48 {
  49    nir_function_impl *impl = nir_shader_get_entrypoint(nir);
  50    assert(impl);
  51
  52    /* Get rid of old derefs before we change the types of the variables */
  53    nir_opt_dce(nir);
  54
  55    nir_builder b;
  56    nir_builder_init(&b, impl);
  57
  58    nir_foreach_block_safe (block, impl) {
  59       nir_foreach_instr_safe (instr, block) {
  60          if (instr->type != nir_instr_type_intrinsic)
  61             continue;
  62
  63          nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
  64          if (intr->intrinsic != nir_intrinsic_store_output)
  65             continue;
  66
  67          if (!lower_output_var(nir, nir_intrinsic_base(intr)))
  68             continue;
  69
  70          b.cursor = nir_before_instr(&intr->instr);
  71          nir_instr_rewrite_src(&intr->instr, &intr->src[0],
  72          nir_src_for_ssa(nir_f2f16(&b, intr->src[0].ssa)));
  73
  74          nir_intrinsic_set_type(intr, nir_type_float16);
  75       }
  76    }
  77 }