1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
/*
* Copyright © 2014 Broadcom
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
/**
* @file vc4_opt_copy_propagation.c
*
* This implements simple copy propagation for QIR without control flow.
*
* For each temp, it keeps a qreg of which source it was MOVed from, if it
* was. If we see that used later, we can just reuse the source value, since
* we know we don't have control flow, and we have SSA for our values so
* there's no killing to worry about.
*/
#include "vc4_qir.h"
bool
qir_opt_copy_propagation(struct vc4_compile *c)
{
bool progress = false;
struct simple_node *node;
bool debug = false;
struct qreg *movs = calloc(c->num_temps, sizeof(struct qreg));
foreach(node, &c->instructions) {
struct qinst *inst = (struct qinst *)node;
/* A single instruction can only read one uniform value. (It
* could maybe read the same uniform value in two operands,
* but that doesn't seem important to do).
*/
bool reads_a_uniform = false;
for (int i = 0; i < qir_get_op_nsrc(inst->op); i++) {
if (inst->src[i].file == QFILE_UNIF)
reads_a_uniform = true;
}
for (int i = 0; i < qir_get_op_nsrc(inst->op); i++) {
int index = inst->src[i].index;
if (inst->src[i].file == QFILE_TEMP &&
(movs[index].file == QFILE_TEMP ||
(movs[index].file == QFILE_UNIF &&
!reads_a_uniform))) {
if (debug) {
fprintf(stderr, "Copy propagate: ");
qir_dump_inst(inst);
fprintf(stderr, "\n");
}
inst->src[i] = movs[index];
if (movs[index].file == QFILE_UNIF)
reads_a_uniform = true;
if (debug) {
fprintf(stderr, "to: ");
qir_dump_inst(inst);
fprintf(stderr, "\n");
}
progress = true;
}
}
if (inst->op == QOP_MOV && inst->dst.file == QFILE_TEMP)
movs[inst->dst.index] = inst->src[0];
}
free(movs);
return progress;
}
|
