grub2: bring back build of aros-side grub2 tools
[AROS.git] / workbench / libs / mesa / src / glsl / opt_constant_folding.cpp
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1 /*
2 * Copyright © 2010 Intel Corporation
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:
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.
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.
24 /**
25 * \file opt_constant_folding.cpp
26 * Replace constant-valued expressions with references to constant values.
29 #include "ir.h"
30 #include "ir_visitor.h"
31 #include "ir_rvalue_visitor.h"
32 #include "ir_optimization.h"
33 #include "glsl_types.h"
35 /**
36 * Visitor class for replacing expressions with ir_constant values.
39 class ir_constant_folding_visitor : public ir_rvalue_visitor {
40 public:
41 ir_constant_folding_visitor()
43 this->progress = false;
46 virtual ~ir_constant_folding_visitor()
48 /* empty */
51 virtual ir_visitor_status visit_enter(ir_assignment *ir);
52 virtual ir_visitor_status visit_enter(ir_call *ir);
54 virtual void handle_rvalue(ir_rvalue **rvalue);
56 bool progress;
59 void
60 ir_constant_folding_visitor::handle_rvalue(ir_rvalue **rvalue)
62 if (*rvalue == NULL || (*rvalue)->ir_type == ir_type_constant)
63 return;
65 /* Note that we do rvalue visitoring on leaving. So if an
66 * expression has a non-constant operand, no need to go looking
67 * down it to find if it's constant. This cuts the time of this
68 * pass down drastically.
70 ir_expression *expr = (*rvalue)->as_expression();
71 if (expr) {
72 for (unsigned int i = 0; i < expr->get_num_operands(); i++) {
73 if (!expr->operands[i]->as_constant())
74 return;
78 ir_constant *constant = (*rvalue)->constant_expression_value();
79 if (constant) {
80 *rvalue = constant;
81 this->progress = true;
82 } else {
83 (*rvalue)->accept(this);
87 ir_visitor_status
88 ir_constant_folding_visitor::visit_enter(ir_assignment *ir)
90 ir->rhs->accept(this);
91 handle_rvalue(&ir->rhs);
93 if (ir->condition) {
94 ir->condition->accept(this);
95 handle_rvalue(&ir->condition);
97 ir_constant *const_val = ir->condition->as_constant();
98 /* If the condition is constant, either remove the condition or
99 * remove the never-executed assignment.
101 if (const_val) {
102 if (const_val->value.b[0])
103 ir->condition = NULL;
104 else
105 ir->remove();
106 this->progress = true;
110 /* Don't descend into the LHS because we want it to stay as a
111 * variable dereference. FINISHME: We probably should to get array
112 * indices though.
114 return visit_continue_with_parent;
117 ir_visitor_status
118 ir_constant_folding_visitor::visit_enter(ir_call *ir)
120 exec_list_iterator sig_iter = ir->get_callee()->parameters.iterator();
121 foreach_iter(exec_list_iterator, iter, *ir) {
122 ir_rvalue *param_rval = (ir_rvalue *)iter.get();
123 ir_variable *sig_param = (ir_variable *)sig_iter.get();
125 if (sig_param->mode == ir_var_in || sig_param->mode == ir_var_const_in) {
126 ir_rvalue *new_param = param_rval;
128 handle_rvalue(&new_param);
129 if (new_param != param_rval) {
130 param_rval->replace_with(new_param);
133 sig_iter.next();
136 return visit_continue_with_parent;
139 bool
140 do_constant_folding(exec_list *instructions)
142 ir_constant_folding_visitor constant_folding;
144 visit_list_elements(&constant_folding, instructions);
146 return constant_folding.progress;