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/*
* Copyright © 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.
*
* Authors:
* Jason Ekstrand (jason@jlekstrand.net)
*
*/
/*
* This lowering pass converts references to variables with loads/stores to
* scratch space based on a few configurable parameters.
*/
#include "nir.h"
#include "nir_builder.h"
#include "nir_deref.h"
static bool
deref_has_indirect(nir_deref_instr *deref)
{
while (deref->deref_type != nir_deref_type_var) {
if (deref->deref_type == nir_deref_type_array &&
nir_src_as_const_value(deref->arr.index) == NULL)
return true;
deref = nir_deref_instr_parent(deref);
}
return false;
}
static void
lower_load_store(nir_builder *b,
nir_intrinsic_instr *intrin,
glsl_type_size_align_func size_align)
{
b->cursor = nir_before_instr(&intrin->instr);
nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
nir_variable *var = nir_deref_instr_get_variable(deref);
nir_ssa_def *offset =
nir_iadd_imm(b, nir_build_deref_offset(b, deref, size_align),
var->data.location);
unsigned align, UNUSED size;
size_align(deref->type, &size, &align);
if (intrin->intrinsic == nir_intrinsic_load_deref) {
nir_intrinsic_instr *load =
nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_scratch);
load->num_components = intrin->num_components;
load->src[0] = nir_src_for_ssa(offset);
nir_intrinsic_set_align(load, align, 0);
nir_ssa_dest_init(&load->instr, &load->dest,
intrin->dest.ssa.num_components,
intrin->dest.ssa.bit_size, NULL);
nir_builder_instr_insert(b, &load->instr);
nir_ssa_def *value = &load->dest.ssa;
if (glsl_type_is_boolean(deref->type))
value = nir_b2i32(b, value);
nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
nir_src_for_ssa(&load->dest.ssa));
} else {
assert(intrin->intrinsic == nir_intrinsic_store_deref);
assert(intrin->src[1].is_ssa);
nir_ssa_def *value = intrin->src[1].ssa;
if (glsl_type_is_boolean(deref->type))
value = nir_i2b(b, value);
nir_intrinsic_instr *store =
nir_intrinsic_instr_create(b->shader, nir_intrinsic_store_scratch);
store->num_components = intrin->num_components;
store->src[0] = nir_src_for_ssa(value);
store->src[1] = nir_src_for_ssa(offset);
nir_intrinsic_set_write_mask(store, nir_intrinsic_write_mask(intrin));
nir_intrinsic_set_align(store, align, 0);
nir_builder_instr_insert(b, &store->instr);
}
nir_instr_remove(&intrin->instr);
nir_deref_instr_remove_if_unused(deref);
}
bool
nir_lower_vars_to_scratch(nir_shader *shader,
nir_variable_mode modes,
int size_threshold,
glsl_type_size_align_func size_align)
{
/* First, we walk the instructions and flag any variables we want to lower
* by removing them from their respective list and setting the mode to 0.
*/
nir_foreach_function(function, shader) {
nir_foreach_block(block, function->impl) {
nir_foreach_instr(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
if (intrin->intrinsic != nir_intrinsic_load_deref &&
intrin->intrinsic != nir_intrinsic_store_deref)
continue;
nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
if (!(deref->mode & modes))
continue;
if (!deref_has_indirect(nir_src_as_deref(intrin->src[0])))
continue;
nir_variable *var = nir_deref_instr_get_variable(deref);
/* We set var->mode to 0 to indicate that a variable will be moved
* to scratch. Don't assign a scratch location twice.
*/
if (var->data.mode == 0)
continue;
unsigned var_size, var_align;
size_align(var->type, &var_size, &var_align);
if (var_size <= size_threshold)
continue;
/* Remove it from its list */
exec_node_remove(&var->node);
/* Invalid mode used to flag "moving to scratch" */
var->data.mode = 0;
var->data.location = ALIGN_POT(shader->scratch_size, var_align);
shader->scratch_size = var->data.location + var_size;
}
}
}
bool progress = false;
nir_foreach_function(function, shader) {
if (!function->impl)
continue;
nir_builder build;
nir_builder_init(&build, function->impl);
bool impl_progress = false;
nir_foreach_block(block, function->impl) {
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
if (intrin->intrinsic != nir_intrinsic_load_deref &&
intrin->intrinsic != nir_intrinsic_store_deref)
continue;
nir_variable *var = nir_intrinsic_get_var(intrin, 0);
/* Variables flagged for lowering above have mode == 0 */
if (!var || var->data.mode)
continue;
lower_load_store(&build, intrin, size_align);
impl_progress = true;
}
}
if (impl_progress) {
progress = true;
nir_metadata_preserve(function->impl, nir_metadata_block_index |
nir_metadata_dominance);
}
}
return progress;
}
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