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#include "ir.h"
24#include "ir_builder.h"
25#include "ir_rvalue_visitor.h"
26#include "ir_optimization.h"
27
28using namespace ir_builder;
29
30namespace {
31
32class vector_insert_visitor : public ir_rvalue_visitor {
33public:
34   vector_insert_visitor(bool lower_nonconstant_index)
35      : progress(false), lower_nonconstant_index(lower_nonconstant_index)
36   {
37      factory.instructions = &factory_instructions;
38   }
39
40   virtual ~vector_insert_visitor()
41   {
42      assert(factory_instructions.is_empty());
43   }
44
45   virtual void handle_rvalue(ir_rvalue **rv);
46
47   ir_factory factory;
48   exec_list factory_instructions;
49   bool progress;
50   bool lower_nonconstant_index;
51};
52
53} /* anonymous namespace */
54
55void
56vector_insert_visitor::handle_rvalue(ir_rvalue **rv)
57{
58   if (*rv == NULL || (*rv)->ir_type != ir_type_expression)
59      return;
60
61   ir_expression *const expr = (ir_expression *) *rv;
62
63   if (likely(expr->operation != ir_triop_vector_insert))
64      return;
65
66   factory.mem_ctx = ralloc_parent(expr);
67
68   ir_constant *const idx = expr->operands[2]->constant_expression_value();
69   if (idx != NULL) {
70      /* Replace (vector_insert (vec) (scalar) (index)) with a dereference of
71       * a new temporary.  The new temporary gets assigned as
72       *
73       *     t = vec
74       *     t.mask = scalar
75       *
76       * where mask is the component selected by index.
77       */
78      ir_variable *const temp =
79         factory.make_temp(expr->operands[0]->type, "vec_tmp");
80
81      const int mask = 1 << idx->value.i[0];
82
83      factory.emit(assign(temp, expr->operands[0]));
84      factory.emit(assign(temp, expr->operands[1], mask));
85
86      this->progress = true;
87      *rv = new(factory.mem_ctx) ir_dereference_variable(temp);
88   } else if (this->lower_nonconstant_index) {
89      /* Replace (vector_insert (vec) (scalar) (index)) with a dereference of
90       * a new temporary.  The new temporary gets assigned as
91       *
92       *     t = vec
93       *     if (index == 0)
94       *         t.x = scalar
95       *     if (index == 1)
96       *         t.y = scalar
97       *     if (index == 2)
98       *         t.z = scalar
99       *     if (index == 3)
100       *         t.w = scalar
101       */
102      ir_variable *const temp =
103         factory.make_temp(expr->operands[0]->type, "vec_tmp");
104
105      ir_variable *const src_temp =
106         factory.make_temp(expr->operands[1]->type, "src_temp");
107
108      factory.emit(assign(temp, expr->operands[0]));
109      factory.emit(assign(src_temp, expr->operands[1]));
110
111      assert(expr->operands[2]->type == glsl_type::int_type ||
112             expr->operands[2]->type == glsl_type::uint_type);
113
114      for (unsigned i = 0; i < expr->type->vector_elements; i++) {
115         ir_constant *const cmp_index =
116            ir_constant::zero(factory.mem_ctx, expr->operands[2]->type);
117         cmp_index->value.u[0] = i;
118
119         ir_variable *const cmp_result =
120            factory.make_temp(glsl_type::bool_type, "index_condition");
121
122         factory.emit(assign(cmp_result,
123                             equal(expr->operands[2]->clone(factory.mem_ctx,
124                                                            NULL),
125                                   cmp_index)));
126
127         factory.emit(if_tree(cmp_result,
128                              assign(temp, src_temp, WRITEMASK_X << i)));
129      }
130
131      this->progress = true;
132      *rv = new(factory.mem_ctx) ir_dereference_variable(temp);
133   }
134
135   base_ir->insert_before(factory.instructions);
136}
137
138bool
139lower_vector_insert(exec_list *instructions, bool lower_nonconstant_index)
140{
141   vector_insert_visitor v(lower_nonconstant_index);
142
143   visit_list_elements(&v, instructions);
144
145   return v.progress;
146}
147