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 opt_noop_swizzle.cpp
26 *
27 * If a swizzle doesn't change the order or count of components, then
28 * remove the swizzle so that other optimization passes see the value
29 * behind it.
30 */
31
32#include "ir.h"
33#include "ir_visitor.h"
34#include "ir_rvalue_visitor.h"
35#include "ir_print_visitor.h"
36#include "glsl_types.h"
37
38namespace {
39
40class ir_noop_swizzle_visitor : public ir_rvalue_visitor {
41public:
42   ir_noop_swizzle_visitor()
43   {
44      this->progress = false;
45   }
46
47   void handle_rvalue(ir_rvalue **rvalue);
48   bool progress;
49};
50
51} /* unnamed namespace */
52
53void
54ir_noop_swizzle_visitor::handle_rvalue(ir_rvalue **rvalue)
55{
56   if (!*rvalue)
57      return;
58
59   ir_swizzle *swiz = (*rvalue)->as_swizzle();
60   if (!swiz || swiz->type != swiz->val->type)
61      return;
62
63   int elems = swiz->val->type->vector_elements;
64   if (swiz->mask.x != 0)
65      return;
66   if (elems >= 2 && swiz->mask.y != 1)
67      return;
68   if (elems >= 3 && swiz->mask.z != 2)
69      return;
70   if (elems >= 4 && swiz->mask.w != 3)
71      return;
72
73   this->progress = true;
74   *rvalue = swiz->val;
75}
76
77bool
78do_noop_swizzle(exec_list *instructions)
79{
80   ir_noop_swizzle_visitor v;
81   visit_list_elements(&v, instructions);
82
83   return v.progress;
84}
85