1/*
2 * Copyright © 2016 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#ifndef OPT_ADD_NEG_TO_SUB_H
25#define OPT_ADD_NEG_TO_SUB_H
26
27#include "ir.h"
28#include "ir_hierarchical_visitor.h"
29
30class add_neg_to_sub_visitor : public ir_hierarchical_visitor {
31public:
32   add_neg_to_sub_visitor()
33   {
34      /* empty */
35   }
36
37   ir_visitor_status visit_leave(ir_expression *ir)
38   {
39      if (ir->operation != ir_binop_add)
40         return visit_continue;
41
42      for (unsigned i = 0; i < 2; i++) {
43         ir_expression *const op = ir->operands[i]->as_expression();
44
45         if (op != NULL && op->operation == ir_unop_neg) {
46            ir->operation = ir_binop_sub;
47
48            /* This ensures that -a + b becomes b - a. */
49            if (i == 0)
50               ir->operands[0] = ir->operands[1];
51
52            ir->operands[1] = op->operands[0];
53            break;
54         }
55      }
56
57      return visit_continue;
58   }
59};
60
61#endif /* OPT_ADD_NEG_TO_SUB_H */
62