1 /*
2 * Mesa 3-D graphics library
3 *
4 * Copyright (C) 2012-2013 LunarG, Inc.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Authors:
25 * Chia-I Wu <olv@lunarg.com>
26 */
27
28 #include "toy_compiler.h"
29 #include "toy_tgsi.h"
30 #include "toy_optimize.h"
31
32 /**
33 * This just eliminates instructions with null dst so far.
34 */
35 static void
eliminate_dead_code(struct toy_compiler * tc)36 eliminate_dead_code(struct toy_compiler *tc)
37 {
38 struct toy_inst *inst;
39
40 tc_head(tc);
41 while ((inst = tc_next(tc)) != NULL) {
42 switch (inst->opcode) {
43 case GEN6_OPCODE_IF:
44 case GEN6_OPCODE_ELSE:
45 case GEN6_OPCODE_ENDIF:
46 case GEN6_OPCODE_WHILE:
47 case GEN6_OPCODE_BREAK:
48 case GEN6_OPCODE_CONT:
49 case GEN6_OPCODE_SEND:
50 case GEN6_OPCODE_SENDC:
51 case GEN6_OPCODE_NOP:
52 /* never eliminated */
53 break;
54 default:
55 if (tdst_is_null(inst->dst) || !inst->dst.writemask) {
56 /* math is always GEN6_COND_NORMAL */
57 if ((inst->opcode == GEN6_OPCODE_MATH ||
58 inst->cond_modifier == GEN6_COND_NONE) &&
59 !inst->acc_wr_ctrl)
60 tc_discard_inst(tc, inst);
61 }
62 break;
63 }
64 }
65 }
66
67 void
toy_compiler_optimize(struct toy_compiler * tc)68 toy_compiler_optimize(struct toy_compiler *tc)
69 {
70 eliminate_dead_code(tc);
71 }
72