src/glsl/ir_expression_flattening.cpp

   1 /*
   2  * Copyright © 2010 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
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * \file ir_expression_flattening.cpp
  26  *
  27  * Takes the leaves of expression trees and makes them dereferences of
  28  * assignments of the leaves to temporaries, according to a predicate.
  29  *
  30  * This is used for breaking down matrix operations, where it's easier to
  31  * create a temporary and work on each of its vector components individually.
  32  */
  33
  34 #include "ir.h"
  35 #include "ir_rvalue_visitor.h"
  36 #include "ir_expression_flattening.h"
  37
  38 class ir_expression_flattening_visitor : public ir_rvalue_visitor {
  39 public:
  40    ir_expression_flattening_visitor(bool (*predicate)(ir_instruction *ir))
  41    {
  42       this->predicate = predicate;
  43    }
  44
  45    virtual ~ir_expression_flattening_visitor()
  46    {
  47       /* empty */
  48    }
  49
  50    void handle_rvalue(ir_rvalue **rvalue);
  51    bool (*predicate)(ir_instruction *ir);
  52 };
  53
  54 void
  55 do_expression_flattening(exec_list *instructions,
  56                          bool (*predicate)(ir_instruction *ir))
  57 {
  58    ir_expression_flattening_visitor v(predicate);
  59
  60    foreach_list(n, instructions) {
  61       ir_instruction *ir = (ir_instruction *) n;
  62
  63       ir->accept(&v);
  64    }
  65 }
  66
  67 void
  68 ir_expression_flattening_visitor::handle_rvalue(ir_rvalue **rvalue)
  69 {
  70    ir_variable *var;
  71    ir_assignment *assign;
  72    ir_rvalue *ir = *rvalue;
  73
  74    if (!ir || !this->predicate(ir))
  75       return;
  76
  77    void *ctx = ralloc_parent(ir);
  78
  79    var = new(ctx) ir_variable(ir->type, "flattening_tmp", ir_var_temporary);
  80    base_ir->insert_before(var);
  81
  82    assign = new(ctx) ir_assignment(new(ctx) ir_dereference_variable(var),
  83                                    ir,
  84                                    NULL);
  85    base_ir->insert_before(assign);
  86
  87    *rvalue = new(ctx) ir_dereference_variable(var);
  88 }