1/*
2 * Copyright © 2013 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 lower_offset_array.cpp
26 *
27 * IR lower pass to decompose ir_texture ir_tg4 with an array of offsets
28 * into four ir_tg4s with a single ivec2 offset, select the .w component of each,
29 * and return those four values packed into a gvec4.
30 *
31 * \author Chris Forbes <chrisf@ijw.co.nz>
32 */
33
34#include "compiler/glsl_types.h"
35#include "ir.h"
36#include "ir_builder.h"
37#include "ir_optimization.h"
38#include "ir_rvalue_visitor.h"
39
40using namespace ir_builder;
41
42class lower_offset_array_visitor : public ir_rvalue_visitor {
43public:
44   lower_offset_array_visitor()
45   {
46      progress = false;
47   }
48
49   void handle_rvalue(ir_rvalue **rv);
50
51   bool progress;
52};
53
54void
55lower_offset_array_visitor::handle_rvalue(ir_rvalue **rv)
56{
57   if (*rv == NULL || (*rv)->ir_type != ir_type_texture)
58      return;
59
60   ir_texture *ir = (ir_texture *) *rv;
61   if (ir->op != ir_tg4 || !ir->offset || !ir->offset->type->is_array())
62      return;
63
64   void *mem_ctx = ralloc_parent(ir);
65
66   ir_variable *var =
67      new (mem_ctx) ir_variable(ir->type, "result", ir_var_temporary);
68   base_ir->insert_before(var);
69
70   for (int i = 0; i < 4; i++) {
71      ir_texture *tex = ir->clone(mem_ctx, NULL);
72      tex->offset = new (mem_ctx) ir_dereference_array(tex->offset,
73            new (mem_ctx) ir_constant(i));
74
75      base_ir->insert_before(assign(var, swizzle_w(tex), 1 << i));
76   }
77
78   *rv = new (mem_ctx) ir_dereference_variable(var);
79
80   progress = true;
81}
82
83bool
84lower_offset_arrays(exec_list *instructions)
85{
86   lower_offset_array_visitor v;
87
88   visit_list_elements(&v, instructions);
89
90   return v.progress;
91}
92