src/glsl/nir/nir_opt_global_to_local.c

   1 /*
   2  * Copyright © 2014 Intel 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  * Authors:
  24  *    Connor Abbott (cwabbott0@gmail.com)
  25  *
  26  */
  27
  28 #include "nir.h"
  29
  30 static bool
  31 global_to_local(nir_register *reg)
  32 {
  33    nir_function_impl *impl = NULL;
  34
  35    assert(reg->is_global);
  36
  37    nir_foreach_def(reg, def_dest) {
  38       nir_instr *instr = def_dest->reg.parent_instr;
  39       nir_function_impl *instr_impl =
  40          nir_cf_node_get_function(&instr->block->cf_node);
  41       if (impl != NULL) {
  42          if (impl != instr_impl)
  43             return false;
  44       } else {
  45          impl = instr_impl;
  46       }
  47    }
  48
  49    nir_foreach_use(reg, use_src) {
  50       nir_instr *instr = use_src->parent_instr;
  51       nir_function_impl *instr_impl =
  52          nir_cf_node_get_function(&instr->block->cf_node);
  53       if (impl != NULL) {
  54          if (impl != instr_impl)
  55             return false;
  56       } else {
  57          impl = instr_impl;
  58       }
  59    }
  60
  61    nir_foreach_if_use(reg, use_src) {
  62       nir_if *if_stmt = use_src->parent_if;
  63       nir_function_impl *if_impl = nir_cf_node_get_function(&if_stmt->cf_node);
  64       if (impl != NULL) {
  65          if (impl != if_impl)
  66             return false;
  67       } else {
  68          impl = if_impl;
  69       }
  70    }
  71
  72    if (impl == NULL) {
  73       /* this instruction is never used/defined, delete it */
  74       nir_reg_remove(reg);
  75       return true;
  76    }
  77
  78    /*
  79     * if we've gotten to this point, the register is always used/defined in
  80     * the same implementation so we can move it to be local to that
  81     * implementation.
  82     */
  83
  84    exec_node_remove(&reg->node);
  85    exec_list_push_tail(&impl->registers, &reg->node);
  86    reg->index = impl->reg_alloc++;
  87    reg->is_global = false;
  88    return true;
  89 }
  90
  91 bool
  92 nir_opt_global_to_local(nir_shader *shader)
  93 {
  94    bool progress = false;
  95
  96    foreach_list_typed_safe(nir_register, reg, node, &shader->registers) {
  97       if (global_to_local(reg))
  98          progress = true;
  99    }
 100
 101    return progress;
 102 }