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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.
*/
#include "nir.h"
#include "nir_builder.h"
#include "nir_deref.h"
static void
emit_load_store_deref(nir_builder *b, nir_intrinsic_instr *orig_instr,
nir_deref_instr *parent,
nir_deref_instr **deref_arr,
nir_ssa_def **dest, nir_ssa_def *src);
static void
emit_indirect_load_store_deref(nir_builder *b, nir_intrinsic_instr *orig_instr,
nir_deref_instr *parent,
nir_deref_instr **deref_arr,
int start, int end,
nir_ssa_def **dest, nir_ssa_def *src)
{
assert(start < end);
if (start == end - 1) {
nir_ssa_def *index = nir_imm_int(b, start);
emit_load_store_deref(b, orig_instr,
nir_build_deref_array(b, parent, index),
deref_arr + 1, dest, src);
} else {
int mid = start + (end - start) / 2;
nir_ssa_def *then_dest, *else_dest;
nir_deref_instr *deref = *deref_arr;
assert(deref->deref_type == nir_deref_type_array);
nir_push_if(b, nir_ilt(b, deref->arr.index.ssa, nir_imm_int(b, mid)));
emit_indirect_load_store_deref(b, orig_instr, parent, deref_arr,
start, mid, &then_dest, src);
nir_push_else(b, NULL);
emit_indirect_load_store_deref(b, orig_instr, parent, deref_arr,
mid, end, &else_dest, src);
nir_pop_if(b, NULL);
if (src == NULL)
*dest = nir_if_phi(b, then_dest, else_dest);
}
}
static void
emit_load_store_deref(nir_builder *b, nir_intrinsic_instr *orig_instr,
nir_deref_instr *parent,
nir_deref_instr **deref_arr,
nir_ssa_def **dest, nir_ssa_def *src)
{
for (; *deref_arr; deref_arr++) {
nir_deref_instr *deref = *deref_arr;
if (deref->deref_type == nir_deref_type_array &&
!nir_src_is_const(deref->arr.index)) {
int length = glsl_get_length(parent->type);
emit_indirect_load_store_deref(b, orig_instr, parent, deref_arr,
0, length, dest, src);
return;
}
parent = nir_build_deref_follower(b, parent, deref);
}
/* We reached the end of the deref chain. Emit the instruction */
assert(*deref_arr == NULL);
if (src == NULL) {
/* This is a load instruction */
nir_intrinsic_instr *load =
nir_intrinsic_instr_create(b->shader, orig_instr->intrinsic);
load->num_components = orig_instr->num_components;
load->src[0] = nir_src_for_ssa(&parent->dest.ssa);
/* Copy over any other sources. This is needed for interp_deref_at */
for (unsigned i = 1;
i < nir_intrinsic_infos[orig_instr->intrinsic].num_srcs; i++)
nir_src_copy(&load->src[i], &orig_instr->src[i], load);
nir_ssa_dest_init(&load->instr, &load->dest,
orig_instr->dest.ssa.num_components,
orig_instr->dest.ssa.bit_size, NULL);
nir_builder_instr_insert(b, &load->instr);
*dest = &load->dest.ssa;
} else {
assert(orig_instr->intrinsic == nir_intrinsic_store_deref);
nir_store_deref(b, parent, src, nir_intrinsic_write_mask(orig_instr));
}
}
static bool
lower_indirect_derefs_block(nir_block *block, nir_builder *b,
nir_variable_mode modes)
{
bool progress = false;
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_interp_deref_at_centroid &&
intrin->intrinsic != nir_intrinsic_interp_deref_at_sample &&
intrin->intrinsic != nir_intrinsic_interp_deref_at_offset &&
intrin->intrinsic != nir_intrinsic_store_deref)
continue;
nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
/* Walk the deref chain back to the base and look for indirects */
bool has_indirect = false;
nir_deref_instr *base = deref;
while (base->deref_type != nir_deref_type_var) {
if (base->deref_type == nir_deref_type_array &&
!nir_src_is_const(base->arr.index))
has_indirect = true;
base = nir_deref_instr_parent(base);
}
if (!has_indirect)
continue;
/* Only lower variables whose mode is in the mask, or compact
* array variables. (We can't handle indirects on tightly packed
* scalar arrays, so we need to lower them regardless.)
*/
if (!(modes & base->var->data.mode) && !base->var->data.compact)
continue;
b->cursor = nir_instr_remove(&intrin->instr);
nir_deref_path path;
nir_deref_path_init(&path, deref, NULL);
assert(path.path[0] == base);
if (intrin->intrinsic == nir_intrinsic_store_deref) {
assert(intrin->src[1].is_ssa);
emit_load_store_deref(b, intrin, base, &path.path[1],
NULL, intrin->src[1].ssa);
} else {
nir_ssa_def *result;
emit_load_store_deref(b, intrin, base, &path.path[1],
&result, NULL);
nir_ssa_def_rewrite_uses(&intrin->dest.ssa, nir_src_for_ssa(result));
}
nir_deref_path_finish(&path);
progress = true;
}
return progress;
}
static bool
lower_indirects_impl(nir_function_impl *impl, nir_variable_mode modes)
{
nir_builder builder;
nir_builder_init(&builder, impl);
bool progress = false;
nir_foreach_block_safe(block, impl) {
progress |= lower_indirect_derefs_block(block, &builder, modes);
}
if (progress)
nir_metadata_preserve(impl, nir_metadata_none);
return progress;
}
/** Lowers indirect variable loads/stores to direct loads/stores.
*
* The pass works by replacing any indirect load or store with an if-ladder
* that does a binary search on the array index.
*/
bool
nir_lower_indirect_derefs(nir_shader *shader, nir_variable_mode modes)
{
bool progress = false;
if (modes == 0)
return false;
nir_foreach_function(function, shader) {
if (function->impl)
progress = lower_indirects_impl(function->impl, modes) || progress;
}
return progress;
}
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