brw_nir_intrinsics.c revision 3ef0957dac11edee7babc9746ec766dcb055d909 
1/*
2 * Copyright (c) 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 DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24#include "brw_nir.h"
25#include "compiler/nir/nir_builder.h"
26
27struct lower_intrinsics_state {
28   nir_shader *nir;
29   union {
30      struct brw_stage_prog_data *prog_data;
31      struct brw_cs_prog_data *cs_prog_data;
32   };
33   nir_function_impl *impl;
34   bool progress;
35   nir_builder builder;
36   bool cs_thread_id_used;
37};
38
39static nir_ssa_def *
40read_thread_local_id(struct lower_intrinsics_state *state)
41{
42   assert(state->cs_prog_data->thread_local_id_index >= 0);
43   state->cs_thread_id_used = true;
44   const int id_index = state->cs_prog_data->thread_local_id_index;
45
46   nir_builder *b = &state->builder;
47   nir_shader *nir = state->nir;
48   nir_intrinsic_instr *load =
49      nir_intrinsic_instr_create(nir, nir_intrinsic_load_uniform);
50   load->num_components = 1;
51   load->src[0] = nir_src_for_ssa(nir_imm_int(b, 0));
52   nir_ssa_dest_init(&load->instr, &load->dest, 1, 32, NULL);
53   nir_intrinsic_set_base(load, id_index * sizeof(uint32_t));
54   nir_intrinsic_set_range(load, sizeof(uint32_t));
55   nir_builder_instr_insert(b, &load->instr);
56   return &load->dest.ssa;
57}
58
59static bool
60lower_cs_intrinsics_convert_block(struct lower_intrinsics_state *state,
61                                  nir_block *block)
62{
63   bool progress = false;
64   nir_builder *b = &state->builder;
65   nir_shader *nir = state->nir;
66
67   nir_foreach_instr_safe(instr, block) {
68      if (instr->type != nir_instr_type_intrinsic)
69         continue;
70
71      nir_intrinsic_instr *intrinsic = nir_instr_as_intrinsic(instr);
72
73      b->cursor = nir_after_instr(&intrinsic->instr);
74
75      nir_ssa_def *sysval;
76      switch (intrinsic->intrinsic) {
77      case nir_intrinsic_load_local_invocation_index: {
78         assert(nir->stage == MESA_SHADER_COMPUTE);
79         /* We construct the local invocation index from:
80          *
81          *    gl_LocalInvocationIndex =
82          *       cs_thread_local_id + channel_num;
83          */
84         nir_ssa_def *thread_local_id = read_thread_local_id(state);
85         nir_ssa_def *channel =
86            nir_load_system_value(b, nir_intrinsic_load_channel_num, 0);
87         sysval = nir_iadd(b, channel, thread_local_id);
88         break;
89      }
90
91      case nir_intrinsic_load_local_invocation_id: {
92         assert(nir->stage == MESA_SHADER_COMPUTE);
93         /* We lower gl_LocalInvocationID from gl_LocalInvocationIndex based
94          * on this formula:
95          *
96          *    gl_LocalInvocationID.x =
97          *       gl_LocalInvocationIndex % gl_WorkGroupSize.x;
98          *    gl_LocalInvocationID.y =
99          *       (gl_LocalInvocationIndex / gl_WorkGroupSize.x) %
100          *       gl_WorkGroupSize.y;
101          *    gl_LocalInvocationID.z =
102          *       (gl_LocalInvocationIndex /
103          *        (gl_WorkGroupSize.x * gl_WorkGroupSize.y)) %
104          *       gl_WorkGroupSize.z;
105          */
106         unsigned *size = nir->info.cs.local_size;
107
108         nir_ssa_def *local_index =
109            nir_load_system_value(b, nir_intrinsic_load_local_invocation_index, 0);
110
111         nir_const_value uvec3;
112         uvec3.u32[0] = 1;
113         uvec3.u32[1] = size[0];
114         uvec3.u32[2] = size[0] * size[1];
115         nir_ssa_def *div_val = nir_build_imm(b, 3, 32, uvec3);
116         uvec3.u32[0] = size[0];
117         uvec3.u32[1] = size[1];
118         uvec3.u32[2] = size[2];
119         nir_ssa_def *mod_val = nir_build_imm(b, 3, 32, uvec3);
120
121         sysval = nir_imod(b, nir_idiv(b, local_index, div_val), mod_val);
122         break;
123      }
124
125      default:
126         continue;
127      }
128
129      nir_ssa_def_rewrite_uses(&intrinsic->dest.ssa, nir_src_for_ssa(sysval));
130      nir_instr_remove(&intrinsic->instr);
131
132      state->progress = true;
133   }
134
135   return progress;
136}
137
138static void
139lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state *state)
140{
141   nir_builder_init(&state->builder, state->impl);
142
143   nir_foreach_block(block, state->impl) {
144      lower_cs_intrinsics_convert_block(state, block);
145   }
146
147   nir_metadata_preserve(state->impl,
148                         nir_metadata_block_index | nir_metadata_dominance);
149}
150
151bool
152brw_nir_lower_intrinsics(nir_shader *nir, struct brw_stage_prog_data *prog_data)
153{
154   /* Currently we only lower intrinsics for compute shaders */
155   if (nir->stage != MESA_SHADER_COMPUTE)
156      return false;
157
158   bool progress = false;
159   struct lower_intrinsics_state state;
160   memset(&state, 0, sizeof(state));
161   state.nir = nir;
162   state.prog_data = prog_data;
163
164   /* Currently this pass only lowers intrinsics using the uniform specified
165    * by thread_local_id_index.
166    */
167   if (nir->stage == MESA_SHADER_COMPUTE &&
168       state.cs_prog_data->thread_local_id_index < 0)
169      return false;
170
171   do {
172      state.progress = false;
173      nir_foreach_function(function, nir) {
174         if (function->impl) {
175            state.impl = function->impl;
176            lower_cs_intrinsics_convert_impl(&state);
177         }
178      }
179      progress |= state.progress;
180   } while (state.progress);
181
182   if (nir->stage == MESA_SHADER_COMPUTE && !state.cs_thread_id_used)
183      state.cs_prog_data->thread_local_id_index = -1;
184
185   return progress;
186}
187