1 /*
2 * Copyright (C) 2020 Collabora, Ltd.
3 * Copyright (C) 2014 Intel Corporation
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * 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 DEALINGS
22 * IN THE SOFTWARE.
23 *
24 * Authors:
25 * Alyssa Rosenzweig <alyssa@collabora.com>
26 * Jason Ekstrand (jason@jlekstrand.net)
27 *
28 */
29
30 #include "nir.h"
31 #include "pan_ir.h"
32
33 /* Check if a given ALU source is the result of a particular componentwise 1-op
34 * ALU source (principally fneg or fabs). If so, return true and rewrite the
35 * source to be the argument, respecting swizzles as needed. If not (or it
36 * cannot be proven), return false and leave the source untouched.
37 */
38
39 bool
pan_has_source_mod(nir_alu_src * src,nir_op op)40 pan_has_source_mod(nir_alu_src *src, nir_op op)
41 {
42 if (!src->src.is_ssa || src->src.ssa->parent_instr->type != nir_instr_type_alu)
43 return false;
44
45 nir_alu_instr *alu = nir_instr_as_alu(src->src.ssa->parent_instr);
46
47 if (alu->op != op)
48 return false;
49
50 /* This only works for unary ops */
51 assert(nir_op_infos[op].num_inputs == 1);
52
53 /* If the copied source is not SSA, moving it might not be valid */
54 if (!alu->src[0].src.is_ssa)
55 return false;
56
57 /* Okay - we've found the modifier we wanted. Let's construct the new ALU
58 * src. In a scalar world, this is just psrc, but for vector archs we need
59 * to respect the swizzle, so we compose.
60 */
61
62 nir_alu_src nsrc = {
63 .src = alu->src[0].src,
64 };
65
66 for (unsigned i = 0; i < NIR_MAX_VEC_COMPONENTS; ++i) {
67 /* (a o b)(i) = a(b(i)) ... swizzle composition is intense. */
68 nsrc.swizzle[i] = alu->src[0].swizzle[src->swizzle[i]];
69 }
70
71 *src = nsrc;
72 return true;
73 }
74
75 /* Check if a given instruction's result will be fed into a
76 * componentwise 1-op ALU instruction (principally fsat without
77 * swizzles). If so, return true and rewrite the destination. The
78 * backend will need to track the new destinations to avoid
79 * incorrect double-emits. */
80
81 bool
pan_has_dest_mod(nir_dest ** odest,nir_op op)82 pan_has_dest_mod(nir_dest **odest, nir_op op)
83 {
84 /* This only works for unary ops */
85 assert(nir_op_infos[op].num_inputs == 1);
86
87 /* If not SSA, this might not be legal */
88 nir_dest *dest = *odest;
89 if (!dest->is_ssa)
90 return false;
91
92 /* Check the uses. We want a single use, with the op `op` */
93 if (!list_is_empty(&dest->ssa.if_uses))
94 return false;
95
96 if (!list_is_singular(&dest->ssa.uses))
97 return false;
98
99 nir_src *use = list_first_entry(&dest->ssa.uses, nir_src, use_link);
100 nir_instr *parent = use->parent_instr;
101
102 /* Check if the op is `op` */
103 if (parent->type != nir_instr_type_alu)
104 return false;
105
106 nir_alu_instr *alu = nir_instr_as_alu(parent);
107 if (alu->op != op)
108 return false;
109
110 /* We can't do expansions without a move in the middle */
111 unsigned nr_components = nir_dest_num_components(alu->dest.dest);
112
113 if (nir_dest_num_components(*dest) != nr_components)
114 return false;
115
116 /* We don't handle swizzles here, so check for the identity */
117 for (unsigned i = 0; i < nr_components; ++i) {
118 if (alu->src[0].swizzle[i] != i)
119 return false;
120 }
121
122 if (!alu->dest.dest.is_ssa)
123 return false;
124
125 /* Otherwise, we're good */
126 *odest = &alu->dest.dest;
127 return true;
128 }
129