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    struct set_entry *entry;
  38    set_foreach(reg->defs, entry) {
  39       nir_instr *instr = (nir_instr *) entry->key;
  40       nir_function_impl *instr_impl =
  41          nir_cf_node_get_function(&instr->block->cf_node);
  42       if (impl != NULL) {
  43          if (impl != instr_impl)
  44             return false;
  45       } else {
  46          impl = instr_impl;
  47       }
  48    }
  49
  50    set_foreach(reg->uses, entry) {
  51       nir_instr *instr = (nir_instr *) entry->key;
  52       nir_function_impl *instr_impl =
  53          nir_cf_node_get_function(&instr->block->cf_node);
  54       if (impl != NULL) {
  55          if (impl != instr_impl)
  56             return false;
  57       } else {
  58          impl = instr_impl;
  59       }
  60    }
  61
  62    set_foreach(reg->if_uses, entry) {
  63       nir_if *if_stmt = (nir_if *) entry->key;
  64       nir_function_impl *if_impl = nir_cf_node_get_function(&if_stmt->cf_node);
  65       if (impl != NULL) {
  66          if (impl != if_impl)
  67             return false;
  68       } else {
  69          impl = if_impl;
  70       }
  71    }
  72
  73    if (impl == NULL) {
  74       /* this instruction is never used/defined, delete it */
  75       nir_reg_remove(reg);
  76       return true;
  77    }
  78
  79    /*
  80     * if we've gotten to this point, the register is always used/defined in
  81     * the same implementation so we can move it to be local to that
  82     * implementation.
  83     */
  84
  85    exec_node_remove(&reg->node);
  86    exec_list_push_tail(&impl->registers, &reg->node);
  87    reg->index = impl->reg_alloc++;
  88    reg->is_global = false;
  89    return true;
  90 }
  91
  92 bool
  93 nir_opt_global_to_local(nir_shader *shader)
  94 {
  95    bool progress = false;
  96
  97    foreach_list_typed_safe(nir_register, reg, node, &shader->registers) {
  98       if (global_to_local(reg))
  99          progress = true;
 100    }
 101
 102    return progress;
 103 }