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/*
* Copyright © 2017 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 "nir.h"
#include "nir_builder.h"
/**
* \file nir_opt_intrinsics.c
*/
/* Converts a uint32_t or uint64_t value to uint64_t or uvec4 */
static nir_ssa_def *
uint_to_ballot_type(nir_builder *b, nir_ssa_def *value,
unsigned num_components, unsigned bit_size)
{
assert(value->num_components == 1);
assert(value->bit_size == 32 || value->bit_size == 64);
nir_ssa_def *zero = nir_imm_int(b, 0);
if (num_components > 1) {
/* SPIR-V uses a uvec4 for ballot values */
assert(num_components == 4);
assert(bit_size == 32);
if (value->bit_size == 32) {
return nir_vec4(b, value, zero, zero, zero);
} else {
assert(value->bit_size == 64);
return nir_vec4(b, nir_unpack_64_2x32_split_x(b, value),
nir_unpack_64_2x32_split_y(b, value),
zero, zero);
}
} else {
/* GLSL uses a uint64_t for ballot values */
assert(num_components == 1);
assert(bit_size == 64);
if (value->bit_size == 32) {
return nir_pack_64_2x32_split(b, value, zero);
} else {
assert(value->bit_size == 64);
return value;
}
}
}
static nir_ssa_def *
lower_read_invocation_to_scalar(nir_builder *b, nir_intrinsic_instr *intrin)
{
/* This is safe to call on scalar things but it would be silly */
assert(intrin->dest.ssa.num_components > 1);
nir_ssa_def *value = nir_ssa_for_src(b, intrin->src[0],
intrin->num_components);
nir_ssa_def *reads[4];
for (unsigned i = 0; i < intrin->num_components; i++) {
nir_intrinsic_instr *chan_intrin =
nir_intrinsic_instr_create(b->shader, intrin->intrinsic);
nir_ssa_dest_init(&chan_intrin->instr, &chan_intrin->dest,
1, intrin->dest.ssa.bit_size, NULL);
chan_intrin->num_components = 1;
/* value */
chan_intrin->src[0] = nir_src_for_ssa(nir_channel(b, value, i));
/* invocation */
if (intrin->intrinsic == nir_intrinsic_read_invocation)
nir_src_copy(&chan_intrin->src[1], &intrin->src[1], chan_intrin);
nir_builder_instr_insert(b, &chan_intrin->instr);
reads[i] = &chan_intrin->dest.ssa;
}
return nir_vec(b, reads, intrin->num_components);
}
static nir_ssa_def *
lower_subgroups_intrin(nir_builder *b, nir_intrinsic_instr *intrin,
const nir_lower_subgroups_options *options)
{
switch (intrin->intrinsic) {
case nir_intrinsic_vote_any:
case nir_intrinsic_vote_all:
if (options->lower_vote_trivial)
return nir_ssa_for_src(b, intrin->src[0], 1);
break;
case nir_intrinsic_vote_eq:
if (options->lower_vote_trivial)
return nir_imm_int(b, NIR_TRUE);
break;
case nir_intrinsic_load_subgroup_size:
if (options->subgroup_size)
return nir_imm_int(b, options->subgroup_size);
break;
case nir_intrinsic_read_invocation:
case nir_intrinsic_read_first_invocation:
if (options->lower_to_scalar && intrin->num_components > 1)
return lower_read_invocation_to_scalar(b, intrin);
break;
case nir_intrinsic_load_subgroup_eq_mask:
case nir_intrinsic_load_subgroup_ge_mask:
case nir_intrinsic_load_subgroup_gt_mask:
case nir_intrinsic_load_subgroup_le_mask:
case nir_intrinsic_load_subgroup_lt_mask: {
if (!options->lower_subgroup_masks)
return NULL;
/* If either the result or the requested bit size is 64-bits then we
* know that we have 64-bit types and using them will probably be more
* efficient than messing around with 32-bit shifts and packing.
*/
const unsigned bit_size = MAX2(options->ballot_bit_size,
intrin->dest.ssa.bit_size);
assert(options->subgroup_size <= 64);
uint64_t group_mask = ~0ull >> (64 - options->subgroup_size);
nir_ssa_def *count = nir_load_subgroup_invocation(b);
nir_ssa_def *val;
switch (intrin->intrinsic) {
case nir_intrinsic_load_subgroup_eq_mask:
val = nir_ishl(b, nir_imm_intN_t(b, 1ull, bit_size), count);
break;
case nir_intrinsic_load_subgroup_ge_mask:
val = nir_iand(b, nir_ishl(b, nir_imm_intN_t(b, ~0ull, bit_size), count),
nir_imm_intN_t(b, group_mask, bit_size));
break;
case nir_intrinsic_load_subgroup_gt_mask:
val = nir_iand(b, nir_ishl(b, nir_imm_intN_t(b, ~1ull, bit_size), count),
nir_imm_intN_t(b, group_mask, bit_size));
break;
case nir_intrinsic_load_subgroup_le_mask:
val = nir_inot(b, nir_ishl(b, nir_imm_intN_t(b, ~1ull, bit_size), count));
break;
case nir_intrinsic_load_subgroup_lt_mask:
val = nir_inot(b, nir_ishl(b, nir_imm_intN_t(b, ~0ull, bit_size), count));
break;
default:
unreachable("you seriously can't tell this is unreachable?");
}
return uint_to_ballot_type(b, val,
intrin->dest.ssa.num_components,
intrin->dest.ssa.bit_size);
}
case nir_intrinsic_ballot: {
if (intrin->dest.ssa.num_components == 1 &&
intrin->dest.ssa.bit_size == options->ballot_bit_size)
return NULL;
nir_intrinsic_instr *ballot =
nir_intrinsic_instr_create(b->shader, nir_intrinsic_ballot);
ballot->num_components = 1;
nir_ssa_dest_init(&ballot->instr, &ballot->dest,
1, options->ballot_bit_size, NULL);
nir_src_copy(&ballot->src[0], &intrin->src[0], ballot);
nir_builder_instr_insert(b, &ballot->instr);
return uint_to_ballot_type(b, &ballot->dest.ssa,
intrin->dest.ssa.num_components,
intrin->dest.ssa.bit_size);
}
default:
break;
}
return NULL;
}
static bool
lower_subgroups_impl(nir_function_impl *impl,
const nir_lower_subgroups_options *options)
{
nir_builder b;
nir_builder_init(&b, impl);
bool progress = false;
nir_foreach_block(block, impl) {
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
b.cursor = nir_before_instr(instr);
nir_ssa_def *lower = lower_subgroups_intrin(&b, intrin, options);
if (!lower)
continue;
nir_ssa_def_rewrite_uses(&intrin->dest.ssa, nir_src_for_ssa(lower));
nir_instr_remove(instr);
progress = true;
}
}
return progress;
}
bool
nir_lower_subgroups(nir_shader *shader,
const nir_lower_subgroups_options *options)
{
bool progress = false;
nir_foreach_function(function, shader) {
if (!function->impl)
continue;
if (lower_subgroups_impl(function->impl, options)) {
progress = true;
nir_metadata_preserve(function->impl, nir_metadata_block_index |
nir_metadata_dominance);
}
}
return progress;
}
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