src/intel/compiler/brw_nir_lower_cs_intrinsics.c - third_party/mesa - Git at Google

 /*
  * Copyright (c) 2016 Intel Corporation
  *
  * 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.
  */

 #include "brw_nir.h"
 #include "compiler/nir/nir_builder.h"

 struct lower_intrinsics_state {
    nir_shader *nir;
    unsigned dispatch_width;
    nir_function_impl *impl;
    bool progress;
    nir_builder builder;
    unsigned local_workgroup_size;
 };

 static bool
 lower_cs_intrinsics_convert_block(struct lower_intrinsics_state *state,
                                   nir_block *block)
 {
    bool progress = false;
    nir_builder *b = &state->builder;
    nir_shader *nir = state->nir;

    /* Reuse calculated values inside the block. */
    nir_ssa_def *local_index = NULL;
    nir_ssa_def *local_id = NULL;

    nir_foreach_instr_safe(instr, block) {
       if (instr->type != nir_instr_type_intrinsic)
          continue;

       nir_intrinsic_instr *intrinsic = nir_instr_as_intrinsic(instr);

       b->cursor = nir_after_instr(&intrinsic->instr);

       nir_ssa_def *sysval;
       switch (intrinsic->intrinsic) {
       case nir_intrinsic_barrier: {
          /* Our HW barrier instruction doesn't do a memory barrier for us but
           * the GLSL barrier() intrinsic does for shared memory.  Insert a
           * shared memory barrier before every barrier().
           */
          b->cursor = nir_before_instr(&intrinsic->instr);

          nir_intrinsic_instr *shared_barrier =
             nir_intrinsic_instr_create(b->shader,
                                        nir_intrinsic_memory_barrier_shared);
          nir_builder_instr_insert(b, &shared_barrier->instr);
          continue;
       }

       case nir_intrinsic_load_local_invocation_index:
       case nir_intrinsic_load_local_invocation_id: {
          /* First time we are using those, so let's calculate them. */
          if (!local_index) {
             assert(!local_id);

             nir_ssa_def *subgroup_id;
             if (state->local_workgroup_size <= state->dispatch_width)
                subgroup_id = nir_imm_int(b, 0);
             else
                subgroup_id = nir_load_subgroup_id(b);

             nir_ssa_def *thread_local_id =
                nir_imul_imm(b, subgroup_id, state->dispatch_width);
             nir_ssa_def *channel = nir_load_subgroup_invocation(b);
             nir_ssa_def *linear = nir_iadd(b, channel, thread_local_id);

             nir_ssa_def *size_x = nir_imm_int(b, nir->info.cs.local_size[0]);
             nir_ssa_def *size_y = nir_imm_int(b, nir->info.cs.local_size[1]);

             /* The local invocation index and ID must respect the following
              *
              *    gl_LocalInvocationID.x =
              *       gl_LocalInvocationIndex % gl_WorkGroupSize.x;
              *    gl_LocalInvocationID.y =
              *       (gl_LocalInvocationIndex / gl_WorkGroupSize.x) %
              *       gl_WorkGroupSize.y;
              *    gl_LocalInvocationID.z =
              *       (gl_LocalInvocationIndex /
              *        (gl_WorkGroupSize.x * gl_WorkGroupSize.y)) %
              *       gl_WorkGroupSize.z;
              *
              * However, the final % gl_WorkGroupSize.z does nothing unless we
              * accidentally end up with a gl_LocalInvocationIndex that is too
              * large so it can safely be omitted.
              */

             if (state->nir->info.cs.derivative_group != DERIVATIVE_GROUP_QUADS) {
                /* If we are not grouping in quads, just set the local invocatio
                 * index linearly, and calculate local invocation ID from that.
                 */
                local_index = linear;

                nir_ssa_def *id_x, *id_y, *id_z;
                id_x = nir_umod(b, local_index, size_x);
                id_y = nir_umod(b, nir_udiv(b, local_index, size_x), size_y);
                id_z = nir_udiv(b, local_index, nir_imul(b, size_x, size_y));
                local_id = nir_vec3(b, id_x, id_y, id_z);
             } else {
                /* For quads, first we figure out the 2x2 grid the invocation
                 * belongs to -- treating extra Z layers as just more rows.
                 * Then map that into local invocation ID (trivial) and local
                 * invocation index.  Skipping Z simplify index calculation.
                 */

                nir_ssa_def *one = nir_imm_int(b, 1);
                nir_ssa_def *double_size_x = nir_ishl(b, size_x, one);

                /* ID within a pair of rows, where each group of 4 is 2x2 quad. */
                nir_ssa_def *row_pair_id = nir_umod(b, linear, double_size_x);
                nir_ssa_def *y_row_pairs = nir_udiv(b, linear, double_size_x);

                nir_ssa_def *x =
                   nir_ior(b,
                           nir_iand(b, row_pair_id, one),
                           nir_iand(b, nir_ishr(b, row_pair_id, one),
                                    nir_imm_int(b, 0xfffffffe)));
                nir_ssa_def *y =
                   nir_ior(b,
                           nir_ishl(b, y_row_pairs, one),
                           nir_iand(b, nir_ishr(b, row_pair_id, one), one));

                local_id = nir_vec3(b, x,
                                    nir_umod(b, y, size_y),
                                    nir_udiv(b, y, size_y));
                local_index = nir_iadd(b, x, nir_imul(b, y, size_x));
             }
          }

          assert(local_id);
          assert(local_index);
          if (intrinsic->intrinsic == nir_intrinsic_load_local_invocation_id)
             sysval = local_id;
          else
             sysval = local_index;
          break;
       }

       case nir_intrinsic_load_subgroup_id:
          if (state->local_workgroup_size > 8)
             continue;

          /* For small workgroup sizes, we know subgroup_id will be zero */
          sysval = nir_imm_int(b, 0);
          break;

       case nir_intrinsic_load_num_subgroups: {
          unsigned local_workgroup_size =
             nir->info.cs.local_size[0] * nir->info.cs.local_size[1] *
             nir->info.cs.local_size[2];
          unsigned num_subgroups =
             DIV_ROUND_UP(local_workgroup_size, state->dispatch_width);
          sysval = nir_imm_int(b, num_subgroups);
          break;
       }

       default:
          continue;
       }

       nir_ssa_def_rewrite_uses(&intrinsic->dest.ssa, nir_src_for_ssa(sysval));
       nir_instr_remove(&intrinsic->instr);

       state->progress = true;
    }

    return progress;
 }

 static void
 lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state *state)
 {
    nir_builder_init(&state->builder, state->impl);

    nir_foreach_block(block, state->impl) {
       lower_cs_intrinsics_convert_block(state, block);
    }

    nir_metadata_preserve(state->impl,
                          nir_metadata_block_index | nir_metadata_dominance);
 }

 bool
 brw_nir_lower_cs_intrinsics(nir_shader *nir,
                             unsigned dispatch_width)
 {
    assert(nir->info.stage == MESA_SHADER_COMPUTE);

    struct lower_intrinsics_state state = {
       .nir = nir,
       .dispatch_width = dispatch_width,
    };

    assert(!nir->info.cs.local_size_variable);
    state.local_workgroup_size = nir->info.cs.local_size[0] *
                                 nir->info.cs.local_size[1] *
                                 nir->info.cs.local_size[2];

    /* Constraints from NV_compute_shader_derivatives. */
    if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_QUADS) {
       assert(nir->info.cs.local_size[0] % 2 == 0);
       assert(nir->info.cs.local_size[1] % 2 == 0);
    } else if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_LINEAR) {
       assert(state.local_workgroup_size % 4 == 0);
    }

    nir_foreach_function(function, nir) {
       if (function->impl) {
          state.impl = function->impl;
          lower_cs_intrinsics_convert_impl(&state);
       }
    }

    return state.progress;
 }
	/*
	* Copyright (c) 2016 Intel Corporation
	*
	* 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.
	*/

	#include "brw_nir.h"
	#include "compiler/nir/nir_builder.h"

	struct lower_intrinsics_state {
	nir_shader *nir;
	unsigned dispatch_width;
	nir_function_impl *impl;
	bool progress;
	nir_builder builder;
	unsigned local_workgroup_size;
	};

	static bool
	lower_cs_intrinsics_convert_block(struct lower_intrinsics_state *state,
	nir_block *block)
	{
	bool progress = false;
	nir_builder *b = &state->builder;
	nir_shader *nir = state->nir;

	/* Reuse calculated values inside the block. */
	nir_ssa_def *local_index = NULL;
	nir_ssa_def *local_id = NULL;

	nir_foreach_instr_safe(instr, block) {
	if (instr->type != nir_instr_type_intrinsic)
	continue;

	nir_intrinsic_instr *intrinsic = nir_instr_as_intrinsic(instr);

	b->cursor = nir_after_instr(&intrinsic->instr);

	nir_ssa_def *sysval;
	switch (intrinsic->intrinsic) {
	case nir_intrinsic_barrier: {
	/* Our HW barrier instruction doesn't do a memory barrier for us but
	* the GLSL barrier() intrinsic does for shared memory. Insert a
	* shared memory barrier before every barrier().
	*/
	b->cursor = nir_before_instr(&intrinsic->instr);

	nir_intrinsic_instr *shared_barrier =
	nir_intrinsic_instr_create(b->shader,
	nir_intrinsic_memory_barrier_shared);
	nir_builder_instr_insert(b, &shared_barrier->instr);
	continue;
	}

	case nir_intrinsic_load_local_invocation_index:
	case nir_intrinsic_load_local_invocation_id: {
	/* First time we are using those, so let's calculate them. */
	if (!local_index) {
	assert(!local_id);

	nir_ssa_def *subgroup_id;
	if (state->local_workgroup_size <= state->dispatch_width)
	subgroup_id = nir_imm_int(b, 0);
	else
	subgroup_id = nir_load_subgroup_id(b);

	nir_ssa_def *thread_local_id =
	nir_imul_imm(b, subgroup_id, state->dispatch_width);
	nir_ssa_def *channel = nir_load_subgroup_invocation(b);
	nir_ssa_def *linear = nir_iadd(b, channel, thread_local_id);

	nir_ssa_def *size_x = nir_imm_int(b, nir->info.cs.local_size[0]);
	nir_ssa_def *size_y = nir_imm_int(b, nir->info.cs.local_size[1]);

	/* The local invocation index and ID must respect the following
	*
	* gl_LocalInvocationID.x =
	* gl_LocalInvocationIndex % gl_WorkGroupSize.x;
	* gl_LocalInvocationID.y =
	* (gl_LocalInvocationIndex / gl_WorkGroupSize.x) %
	* gl_WorkGroupSize.y;
	* gl_LocalInvocationID.z =
	* (gl_LocalInvocationIndex /
	* (gl_WorkGroupSize.x * gl_WorkGroupSize.y)) %
	* gl_WorkGroupSize.z;
	*
	* However, the final % gl_WorkGroupSize.z does nothing unless we
	* accidentally end up with a gl_LocalInvocationIndex that is too
	* large so it can safely be omitted.
	*/

	if (state->nir->info.cs.derivative_group != DERIVATIVE_GROUP_QUADS) {
	/* If we are not grouping in quads, just set the local invocatio
	* index linearly, and calculate local invocation ID from that.
	*/
	local_index = linear;

	nir_ssa_def id_x, id_y, *id_z;
	id_x = nir_umod(b, local_index, size_x);
	id_y = nir_umod(b, nir_udiv(b, local_index, size_x), size_y);
	id_z = nir_udiv(b, local_index, nir_imul(b, size_x, size_y));
	local_id = nir_vec3(b, id_x, id_y, id_z);
	} else {
	/* For quads, first we figure out the 2x2 grid the invocation
	* belongs to -- treating extra Z layers as just more rows.
	* Then map that into local invocation ID (trivial) and local
	* invocation index. Skipping Z simplify index calculation.
	*/

	nir_ssa_def *one = nir_imm_int(b, 1);
	nir_ssa_def *double_size_x = nir_ishl(b, size_x, one);

	/* ID within a pair of rows, where each group of 4 is 2x2 quad. */
	nir_ssa_def *row_pair_id = nir_umod(b, linear, double_size_x);
	nir_ssa_def *y_row_pairs = nir_udiv(b, linear, double_size_x);

	nir_ssa_def *x =
	nir_ior(b,
	nir_iand(b, row_pair_id, one),
	nir_iand(b, nir_ishr(b, row_pair_id, one),
	nir_imm_int(b, 0xfffffffe)));
	nir_ssa_def *y =
	nir_ior(b,
	nir_ishl(b, y_row_pairs, one),
	nir_iand(b, nir_ishr(b, row_pair_id, one), one));

	local_id = nir_vec3(b, x,
	nir_umod(b, y, size_y),
	nir_udiv(b, y, size_y));
	local_index = nir_iadd(b, x, nir_imul(b, y, size_x));
	}
	}

	assert(local_id);
	assert(local_index);
	if (intrinsic->intrinsic == nir_intrinsic_load_local_invocation_id)
	sysval = local_id;
	else
	sysval = local_index;
	break;
	}

	case nir_intrinsic_load_subgroup_id:
	if (state->local_workgroup_size > 8)
	continue;

	/* For small workgroup sizes, we know subgroup_id will be zero */
	sysval = nir_imm_int(b, 0);
	break;

	case nir_intrinsic_load_num_subgroups: {
	unsigned local_workgroup_size =
	nir->info.cs.local_size[0] * nir->info.cs.local_size[1] *
	nir->info.cs.local_size[2];
	unsigned num_subgroups =
	DIV_ROUND_UP(local_workgroup_size, state->dispatch_width);
	sysval = nir_imm_int(b, num_subgroups);
	break;
	}

	default:
	continue;
	}

	nir_ssa_def_rewrite_uses(&intrinsic->dest.ssa, nir_src_for_ssa(sysval));
	nir_instr_remove(&intrinsic->instr);

	state->progress = true;
	}

	return progress;
	}

	static void
	lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state *state)
	{
	nir_builder_init(&state->builder, state->impl);

	nir_foreach_block(block, state->impl) {
	lower_cs_intrinsics_convert_block(state, block);
	}

	nir_metadata_preserve(state->impl,
	nir_metadata_block_index \| nir_metadata_dominance);
	}

	bool
	brw_nir_lower_cs_intrinsics(nir_shader *nir,
	unsigned dispatch_width)
	{
	assert(nir->info.stage == MESA_SHADER_COMPUTE);

	struct lower_intrinsics_state state = {
	.nir = nir,
	.dispatch_width = dispatch_width,
	};

	assert(!nir->info.cs.local_size_variable);
	state.local_workgroup_size = nir->info.cs.local_size[0] *
	nir->info.cs.local_size[1] *
	nir->info.cs.local_size[2];

	/* Constraints from NV_compute_shader_derivatives. */
	if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_QUADS) {
	assert(nir->info.cs.local_size[0] % 2 == 0);
	assert(nir->info.cs.local_size[1] % 2 == 0);
	} else if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_LINEAR) {
	assert(state.local_workgroup_size % 4 == 0);
	}

	nir_foreach_function(function, nir) {
	if (function->impl) {
	state.impl = function->impl;
	lower_cs_intrinsics_convert_impl(&state);
	}
	}

	return state.progress;
	}