src/intel/compiler/brw_nir_lower_cs_intrinsics.c

   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
  27 struct lower_intrinsics_state {
  28    nir_shader *nir;
  29    nir_function_impl *impl;
  30    bool progress;
  31    nir_builder builder;
  32 };
  33
  34 static bool
  35 lower_cs_intrinsics_convert_block(struct lower_intrinsics_state *state,
  36                                   nir_block *block)
  37 {
  38    bool progress = false;
  39    nir_builder *b = &state->builder;
  40    nir_shader *nir = state->nir;
  41
  42    /* Reuse calculated values inside the block. */
  43    nir_ssa_def *local_index = NULL;
  44    nir_ssa_def *local_id = NULL;
  45
  46    nir_foreach_instr_safe(instr, block) {
  47       if (instr->type != nir_instr_type_intrinsic)
  48          continue;
  49
  50       nir_intrinsic_instr *intrinsic = nir_instr_as_intrinsic(instr);
  51
  52       b->cursor = nir_after_instr(&intrinsic->instr);
  53
  54       nir_ssa_def *sysval;
  55       switch (intrinsic->intrinsic) {
  56       case nir_intrinsic_load_local_group_size:
  57       case nir_intrinsic_load_work_group_id:
  58       case nir_intrinsic_load_num_work_groups:
  59          /* Convert this to 32-bit if it's not */
  60          if (intrinsic->dest.ssa.bit_size == 64) {
  61             intrinsic->dest.ssa.bit_size = 32;
  62             sysval = nir_u2u64(b, &intrinsic->dest.ssa);
  63             nir_ssa_def_rewrite_uses_after(&intrinsic->dest.ssa,
  64                                            nir_src_for_ssa(sysval),
  65                                            sysval->parent_instr);
  66          }
  67          continue;
  68
  69       case nir_intrinsic_load_local_invocation_index:
  70       case nir_intrinsic_load_local_invocation_id: {
  71          /* First time we are using those, so let's calculate them. */
  72          if (!local_index) {
  73             assert(!local_id);
  74
  75             nir_ssa_def *subgroup_id = nir_load_subgroup_id(b);
  76
  77             nir_ssa_def *thread_local_id =
  78                nir_imul(b, subgroup_id, nir_load_simd_width_intel(b));
  79             nir_ssa_def *channel = nir_load_subgroup_invocation(b);
  80             nir_ssa_def *linear = nir_iadd(b, channel, thread_local_id);
  81
  82             nir_ssa_def *size_x;
  83             nir_ssa_def *size_y;
  84             if (state->nir->info.cs.local_size_variable) {
  85                nir_ssa_def *size_xyz = nir_load_local_group_size(b);
  86                size_x = nir_channel(b, size_xyz, 0);
  87                size_y = nir_channel(b, size_xyz, 1);
  88             } else {
  89                size_x = nir_imm_int(b, nir->info.cs.local_size[0]);
  90                size_y = nir_imm_int(b, nir->info.cs.local_size[1]);
  91             }
  92
  93             /* The local invocation index and ID must respect the following
  94              *
  95              *    gl_LocalInvocationID.x =
  96              *       gl_LocalInvocationIndex % gl_WorkGroupSize.x;
  97              *    gl_LocalInvocationID.y =
  98              *       (gl_LocalInvocationIndex / gl_WorkGroupSize.x) %
  99              *       gl_WorkGroupSize.y;
 100              *    gl_LocalInvocationID.z =
 101              *       (gl_LocalInvocationIndex /
 102              *        (gl_WorkGroupSize.x * gl_WorkGroupSize.y)) %
 103              *       gl_WorkGroupSize.z;
 104              *
 105              * However, the final % gl_WorkGroupSize.z does nothing unless we
 106              * accidentally end up with a gl_LocalInvocationIndex that is too
 107              * large so it can safely be omitted.
 108              */
 109
 110             if (state->nir->info.cs.derivative_group != DERIVATIVE_GROUP_QUADS) {
 111                /* If we are not grouping in quads, just set the local invocatio
 112                 * index linearly, and calculate local invocation ID from that.
 113                 */
 114                local_index = linear;
 115
 116                nir_ssa_def *id_x, *id_y, *id_z;
 117                id_x = nir_umod(b, local_index, size_x);
 118                id_y = nir_umod(b, nir_udiv(b, local_index, size_x), size_y);
 119                id_z = nir_udiv(b, local_index, nir_imul(b, size_x, size_y));
 120                local_id = nir_vec3(b, id_x, id_y, id_z);
 121             } else {
 122                /* For quads, first we figure out the 2x2 grid the invocation
 123                 * belongs to -- treating extra Z layers as just more rows.
 124                 * Then map that into local invocation ID (trivial) and local
 125                 * invocation index.  Skipping Z simplify index calculation.
 126                 */
 127
 128                nir_ssa_def *one = nir_imm_int(b, 1);
 129                nir_ssa_def *double_size_x = nir_ishl(b, size_x, one);
 130
 131                /* ID within a pair of rows, where each group of 4 is 2x2 quad. */
 132                nir_ssa_def *row_pair_id = nir_umod(b, linear, double_size_x);
 133                nir_ssa_def *y_row_pairs = nir_udiv(b, linear, double_size_x);
 134
 135                nir_ssa_def *x =
 136                   nir_ior(b,
 137                           nir_iand(b, row_pair_id, one),
 138                           nir_iand(b, nir_ishr(b, row_pair_id, one),
 139                                    nir_imm_int(b, 0xfffffffe)));
 140                nir_ssa_def *y =
 141                   nir_ior(b,
 142                           nir_ishl(b, y_row_pairs, one),
 143                           nir_iand(b, nir_ishr(b, row_pair_id, one), one));
 144
 145                local_id = nir_vec3(b, x,
 146                                    nir_umod(b, y, size_y),
 147                                    nir_udiv(b, y, size_y));
 148                local_index = nir_iadd(b, x, nir_imul(b, y, size_x));
 149             }
 150          }
 151
 152          assert(local_id);
 153          assert(local_index);
 154          if (intrinsic->intrinsic == nir_intrinsic_load_local_invocation_id)
 155             sysval = local_id;
 156          else
 157             sysval = local_index;
 158          break;
 159       }
 160
 161       case nir_intrinsic_load_num_subgroups: {
 162          nir_ssa_def *size;
 163          if (state->nir->info.cs.local_size_variable) {
 164             nir_ssa_def *size_xyz = nir_load_local_group_size(b);
 165             nir_ssa_def *size_x = nir_channel(b, size_xyz, 0);
 166             nir_ssa_def *size_y = nir_channel(b, size_xyz, 1);
 167             nir_ssa_def *size_z = nir_channel(b, size_xyz, 2);
 168             size = nir_imul(b, nir_imul(b, size_x, size_y), size_z);
 169          } else {
 170             size = nir_imm_int(b, nir->info.cs.local_size[0] *
 171                                   nir->info.cs.local_size[1] *
 172                                   nir->info.cs.local_size[2]);
 173          }
 174
 175          /* Calculate the equivalent of DIV_ROUND_UP. */
 176          nir_ssa_def *simd_width = nir_load_simd_width_intel(b);
 177          sysval =
 178             nir_udiv(b, nir_iadd_imm(b, nir_iadd(b, size, simd_width), -1),
 179                         simd_width);
 180          break;
 181       }
 182
 183       default:
 184          continue;
 185       }
 186
 187       if (intrinsic->dest.ssa.bit_size == 64)
 188          sysval = nir_u2u64(b, sysval);
 189
 190       nir_ssa_def_rewrite_uses(&intrinsic->dest.ssa, nir_src_for_ssa(sysval));
 191       nir_instr_remove(&intrinsic->instr);
 192
 193       state->progress = true;
 194    }
 195
 196    return progress;
 197 }
 198
 199 static void
 200 lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state *state)
 201 {
 202    nir_builder_init(&state->builder, state->impl);
 203
 204    nir_foreach_block(block, state->impl) {
 205       lower_cs_intrinsics_convert_block(state, block);
 206    }
 207
 208    nir_metadata_preserve(state->impl,
 209                          nir_metadata_block_index | nir_metadata_dominance);
 210 }
 211
 212 bool
 213 brw_nir_lower_cs_intrinsics(nir_shader *nir)
 214 {
 215    assert(nir->info.stage == MESA_SHADER_COMPUTE ||
 216           nir->info.stage == MESA_SHADER_KERNEL);
 217
 218    struct lower_intrinsics_state state = {
 219       .nir = nir,
 220    };
 221
 222    /* Constraints from NV_compute_shader_derivatives. */
 223    if (!nir->info.cs.local_size_variable) {
 224       if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_QUADS) {
 225          assert(nir->info.cs.local_size[0] % 2 == 0);
 226          assert(nir->info.cs.local_size[1] % 2 == 0);
 227       } else if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_LINEAR) {
 228          ASSERTED unsigned local_workgroup_size =
 229             nir->info.cs.local_size[0] *
 230             nir->info.cs.local_size[1] *
 231             nir->info.cs.local_size[2];
 232          assert(local_workgroup_size % 4 == 0);
 233       }
 234    }
 235
 236    nir_foreach_function(function, nir) {
 237       if (function->impl) {
 238          state.impl = function->impl;
 239          lower_cs_intrinsics_convert_impl(&state);
 240       }
 241    }
 242
 243    return state.progress;
 244 }