1/*
2 * Copyright © 2017 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 DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24#include "nir.h"
25#include "nir_builder.h"
26
27/**
28 * \file nir_opt_intrinsics.c
29 */
30
31static bool
32opt_intrinsics_impl(nir_function_impl *impl,
33                    const struct nir_shader_compiler_options *options)
34{
35   nir_builder b;
36   nir_builder_init(&b, impl);
37   bool progress = false;
38
39   nir_foreach_block(block, impl) {
40      nir_foreach_instr_safe(instr, block) {
41         if (instr->type != nir_instr_type_intrinsic)
42            continue;
43
44         nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
45         nir_ssa_def *replacement = NULL;
46         b.cursor = nir_before_instr(instr);
47
48         switch (intrin->intrinsic) {
49         case nir_intrinsic_vote_any:
50         case nir_intrinsic_vote_all:
51            if (nir_src_is_const(intrin->src[0]))
52               replacement = nir_ssa_for_src(&b, intrin->src[0], 1);
53            break;
54         case nir_intrinsic_vote_feq:
55         case nir_intrinsic_vote_ieq:
56            if (nir_src_is_const(intrin->src[0]))
57               replacement = nir_imm_true(&b);
58            break;
59         case nir_intrinsic_load_sample_mask_in:
60            /* Transform:
61             *   gl_SampleMaskIn == 0 ---> gl_HelperInvocation
62             *   gl_SampleMaskIn != 0 ---> !gl_HelperInvocation
63             */
64            if (!options->optimize_sample_mask_in)
65               continue;
66
67            nir_foreach_use_safe(use_src, &intrin->dest.ssa) {
68               if (use_src->parent_instr->type == nir_instr_type_alu) {
69                  nir_alu_instr *alu = nir_instr_as_alu(use_src->parent_instr);
70
71                  if (alu->op == nir_op_ieq ||
72                      alu->op == nir_op_ine) {
73                     /* Check for 0 in either operand. */
74                     nir_const_value *const_val =
75                         nir_src_as_const_value(alu->src[0].src);
76                     if (!const_val)
77                        const_val = nir_src_as_const_value(alu->src[1].src);
78                     if (!const_val || const_val->i32 != 0)
79                        continue;
80
81                     nir_ssa_def *new_expr = nir_load_helper_invocation(&b, 1);
82
83                     if (alu->op == nir_op_ine)
84                        new_expr = nir_inot(&b, new_expr);
85
86                     nir_ssa_def_rewrite_uses(&alu->dest.dest.ssa,
87                                              nir_src_for_ssa(new_expr));
88                     nir_instr_remove(&alu->instr);
89                     continue;
90                  }
91               }
92            }
93            continue;
94         default:
95            break;
96         }
97
98         if (!replacement)
99            continue;
100
101         nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
102                                  nir_src_for_ssa(replacement));
103         nir_instr_remove(instr);
104         progress = true;
105      }
106   }
107
108   return progress;
109}
110
111bool
112nir_opt_intrinsics(nir_shader *shader)
113{
114   bool progress = false;
115
116   nir_foreach_function(function, shader) {
117      if (!function->impl)
118         continue;
119
120      if (opt_intrinsics_impl(function->impl, shader->options)) {
121         progress = true;
122         nir_metadata_preserve(function->impl, nir_metadata_block_index |
123                                               nir_metadata_dominance);
124      }
125   }
126
127   return progress;
128}
129