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_visitor.h"
36#include "ir_rvalue_visitor.h"
37#include "ir_expression_flattening.h"
38#include "glsl_types.h"
39
40class ir_expression_flattening_visitor : public ir_rvalue_visitor {
41public:
42   ir_expression_flattening_visitor(bool (*predicate)(ir_instruction *ir))
43   {
44      this->predicate = predicate;
45   }
46
47   virtual ~ir_expression_flattening_visitor()
48   {
49      /* empty */
50   }
51
52   void handle_rvalue(ir_rvalue **rvalue);
53   bool (*predicate)(ir_instruction *ir);
54};
55
56void
57do_expression_flattening(exec_list *instructions,
58			 bool (*predicate)(ir_instruction *ir))
59{
60   ir_expression_flattening_visitor v(predicate);
61
62   foreach_iter(exec_list_iterator, iter, *instructions) {
63      ir_instruction *ir = (ir_instruction *)iter.get();
64
65      ir->accept(&v);
66   }
67}
68
69void
70ir_expression_flattening_visitor::handle_rvalue(ir_rvalue **rvalue)
71{
72   ir_variable *var;
73   ir_assignment *assign;
74   ir_rvalue *ir = *rvalue;
75
76   if (!ir || !this->predicate(ir))
77      return;
78
79   void *ctx = ralloc_parent(ir);
80
81   var = new(ctx) ir_variable(ir->type, "flattening_tmp", ir_var_temporary);
82   base_ir->insert_before(var);
83
84   assign = new(ctx) ir_assignment(new(ctx) ir_dereference_variable(var),
85				   ir,
86				   NULL);
87   base_ir->insert_before(assign);
88
89   *rvalue = new(ctx) ir_dereference_variable(var);
90}
91