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_swizzle_swizzle.cpp
26 *
27 * Eliminates the second swizzle in a swizzle chain.
28 */
29
30#include "ir.h"
31#include "ir_visitor.h"
32#include "ir_optimization.h"
33#include "glsl_types.h"
34
35namespace {
36
37class ir_swizzle_swizzle_visitor : public ir_hierarchical_visitor {
38public:
39   ir_swizzle_swizzle_visitor()
40   {
41      progress = false;
42   }
43
44   virtual ir_visitor_status visit_enter(ir_swizzle *);
45
46   bool progress;
47};
48
49} /* unnamed namespace */
50
51ir_visitor_status
52ir_swizzle_swizzle_visitor::visit_enter(ir_swizzle *ir)
53{
54   int mask2[4];
55
56   ir_swizzle *swiz2 = ir->val->as_swizzle();
57   if (!swiz2)
58      return visit_continue;
59
60   memset(&mask2, 0, sizeof(mask2));
61   if (swiz2->mask.num_components >= 1)
62      mask2[0] = swiz2->mask.x;
63   if (swiz2->mask.num_components >= 2)
64      mask2[1] = swiz2->mask.y;
65   if (swiz2->mask.num_components >= 3)
66      mask2[2] = swiz2->mask.z;
67   if (swiz2->mask.num_components >= 4)
68      mask2[3] = swiz2->mask.w;
69
70   if (ir->mask.num_components >= 1)
71      ir->mask.x = mask2[ir->mask.x];
72   if (ir->mask.num_components >= 2)
73      ir->mask.y = mask2[ir->mask.y];
74   if (ir->mask.num_components >= 3)
75      ir->mask.z = mask2[ir->mask.z];
76   if (ir->mask.num_components >= 4)
77      ir->mask.w = mask2[ir->mask.w];
78
79   ir->val = swiz2->val;
80
81   this->progress = true;
82
83   return visit_continue;
84}
85
86/**
87 * Does a copy propagation pass on the code present in the instruction stream.
88 */
89bool
90do_swizzle_swizzle(exec_list *instructions)
91{
92   ir_swizzle_swizzle_visitor v;
93
94   v.run(instructions);
95
96   return v.progress;
97}
98